Loading ...
Sorry, an error occurred while loading the content.

Re: [regsaudioforum] Measuring line sources

Expand Messages
  • Alan Jordan
    Hi Robert, The response of the soundline speakers (at the listening position) is fairly easy to fix with 1/3 octave EQ. Still there are a couple of anomalies
    Message 1 of 12 , Feb 21, 2013
    • 0 Attachment
      Hi Robert,

      The response of the soundline speakers (at the listening position) is fairly easy to fix with 1/3 octave EQ.  Still there are a couple of anomalies I would like to bring your attention that are stable over space, are shown in both speakers, so seem to be an issue of the panels.  Maybe you can let me know if they are normal and expected.

      First, there is a 3 dB dip about 1/3 octave in width centered at around 10 kHz.  It looks like a very smooth swoop in response.

      Second, you mentioned not messing with the natural roll-off of the extreme top end.  The response of the panel takes a dive starting about 13 or 14 kHz and is about 13 dB down at 20 kHz.  This is the same whether measured at 1 meter or three meters on axis.  I know its been almost a decade ago, but do you recall similar behavior in the pair you measured?

      Thanks,
      Alan

      On Wed, Feb 20, 2013 at 7:35 PM, Robert <regtas43@...> wrote:
       

      Lots of words on this, but somehow
      the essential point is (to my eyes)
      still not made all that clear:
      A line source measured up close has
      a detailed response that is highly dependent
      on vertical position.
      Overall, in listening terms, line sources
      are not so sensitive to height. But the microstructure
      is so sensitive.
      DO NOT CORRECT THE MICROSTRUCTURE of a close
      up measurement. This will make a rather
      uncolored sounding speaker into a colored
      one.

      WIth the Holm, you have the option of backing up.
      Back off the microphone (for the above 300 measurement)
      in stages until you get something that is fairly stable
      with respect to vertical position. Then correct that.

      A line source--or a quasi line source(the Soundlines
      are not a true line source at 300 Hz say---too short
      a quasi ribbon for that)--has to be corrected
      carefully. You definitely do not want to "correct"
      the zigs and zags in response that arise because
      of the finite length of the line source.

      Actually the best results would probably be
      to smooth out the 1/3 octave RTA at the listening
      position and retain its natural roll off in the
      extreme top. Of course this is actually the
      best thing to do in most cases, even though
      DSP people hate to admit this. Fix spatially
      stable effects, and that is all.

      REG

      __
    • Edward
      Hi Alan While we are waiting for Robert to take up your question below, how do the Soundlines sound so far? Best Edward
      Message 2 of 12 , Feb 23, 2013
      • 0 Attachment
        Hi Alan

        While we are waiting for Robert to take up your question below, how do the Soundlines sound so far?

        Best
        Edward

        --- In regsaudioforum@yahoogroups.com, Alan Jordan <aljordan@...> wrote:
        >
        > Hi Robert,
        >
        > The response of the soundline speakers (at the listening position) is
        > fairly easy to fix with 1/3 octave EQ. Still there are a couple of
        > anomalies I would like to bring your attention that are stable over space,
        > are shown in both speakers, so seem to be an issue of the panels. Maybe
        > you can let me know if they are normal and expected.
        >
        > First, there is a 3 dB dip about 1/3 octave in width centered at around 10
        > kHz. It looks like a very smooth swoop in response.
        >
        > Second, you mentioned not messing with the natural roll-off of the extreme
        > top end. The response of the panel takes a dive starting about 13 or 14
        > kHz and is about 13 dB down at 20 kHz. This is the same whether measured
        > at 1 meter or three meters on axis. I know its been almost a decade ago,
        > but do you recall similar behavior in the pair you measured?
        >
        > Thanks,
        > Alan
        >
        > On Wed, Feb 20, 2013 at 7:35 PM, Robert <regtas43@...> wrote:
        >
        > > **
        > >
        > >
        > > Lots of words on this, but somehow
        > > the essential point is (to my eyes)
        > > still not made all that clear:
        > > A line source measured up close has
        > > a detailed response that is highly dependent
        > > on vertical position.
        > > Overall, in listening terms, line sources
        > > are not so sensitive to height. But the microstructure
        > > is so sensitive.
        > > DO NOT CORRECT THE MICROSTRUCTURE of a close
        > > up measurement. This will make a rather
        > > uncolored sounding speaker into a colored
        > > one.
        > >
        > > WIth the Holm, you have the option of backing up.
        > > Back off the microphone (for the above 300 measurement)
        > > in stages until you get something that is fairly stable
        > > with respect to vertical position. Then correct that.
        > >
        > > A line source--or a quasi line source(the Soundlines
        > > are not a true line source at 300 Hz say---too short
        > > a quasi ribbon for that)--has to be corrected
        > > carefully. You definitely do not want to "correct"
        > > the zigs and zags in response that arise because
        > > of the finite length of the line source.
        > >
        > > Actually the best results would probably be
        > > to smooth out the 1/3 octave RTA at the listening
        > > position and retain its natural roll off in the
        > > extreme top. Of course this is actually the
        > > best thing to do in most cases, even though
        > > DSP people hate to admit this. Fix spatially
        > > stable effects, and that is all.
        > >
        > > REG
        > >
        > > __
        > >
        >
      • Alan Jordan
        Hi Edward, Overall they sound quite good. In fact, for the price, I feel like I ve won a small lottery. The bass needs some EQ, as well as a little bit
        Message 3 of 12 , Feb 23, 2013
        • 0 Attachment
          Hi Edward, 

          Overall they sound quite good.  In fact, for the price, I feel like I've won a small lottery.  The bass needs some EQ, as well as a little bit around the 1 kHz region, but otherwise they need less fussing than my other speakers for proper tonal balance.  The bass doesn't go as deep as my other speakers (which are solid down to 25 Hz), but that is not noticeable on many recordings.  The mid and high frequencies are very smooth and open sounding.  For instance, I was listening to a recording of only a harp and a violin just now, and the sound was so luscious I began looking around for the angel and cherubs.

          They are really quite a treat on large scale symphonic music, in that they are very "open" sounding with very good presence.  On some recordings the soundstage effects regarding depth seems quite a trick: definitely the largest front to back spread I've ever heard in any system, even very expensive systems in big rooms at high end audio shops.  The speakers are holographic in that sense.

          Compared to my other speakers, on some recordings the individual instruments can sound a bit ephemeral - less solid.  Some of the images tend to float in space, well above the plane of my ear height, and have a bit less bite than that of my box speakers.  I don't know if this is caused by the dipole bounce off the back wall or not.  I have the speakers about 8 feet out from the wall behind them, and some foam type traps on the back wall, but I don't have anywhere near the entire back wall damped like some members here seem to do with their dipole speakers.  

          So overall they have a quite different presentation that benefits some recordings but can sometimes detract from other recordings.  Tonally they sound good.

          At this point I'll most likely be keeping both pairs.  If my wife asks me what I need with two pair of speakers, I'll ask her what she needs with three horses, and all will be well.

          Alan  

          On Sat, Feb 23, 2013 at 3:33 PM, Edward <Edward_Wu@...> wrote:
           

          Hi Alan

          While we are waiting for Robert to take up your question below, how do the Soundlines sound so far?

          Best
          Edward



          --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
          >
          > Hi Robert,
          >
          > The response of the soundline speakers (at the listening position) is
          > fairly easy to fix with 1/3 octave EQ. Still there are a couple of
          > anomalies I would like to bring your attention that are stable over space,
          > are shown in both speakers, so seem to be an issue of the panels. Maybe
          > you can let me know if they are normal and expected.
          >
          > First, there is a 3 dB dip about 1/3 octave in width centered at around 10
          > kHz. It looks like a very smooth swoop in response.
          >
          > Second, you mentioned not messing with the natural roll-off of the extreme
          > top end. The response of the panel takes a dive starting about 13 or 14
          > kHz and is about 13 dB down at 20 kHz. This is the same whether measured
          > at 1 meter or three meters on axis. I know its been almost a decade ago,
          > but do you recall similar behavior in the pair you measured?
          >
          > Thanks,
          > Alan
          >
          > On Wed, Feb 20, 2013 at 7:35 PM, Robert wrote:
          >
          > > **

          > >
          > >
          > > Lots of words on this, but somehow
          > > the essential point is (to my eyes)
          > > still not made all that clear:
          > > A line source measured up close has
          > > a detailed response that is highly dependent
          > > on vertical position.
          > > Overall, in listening terms, line sources
          > > are not so sensitive to height. But the microstructure
          > > is so sensitive.
          > > DO NOT CORRECT THE MICROSTRUCTURE of a close
          > > up measurement. This will make a rather
          > > uncolored sounding speaker into a colored
          > > one.
          > >
          > > WIth the Holm, you have the option of backing up.
          > > Back off the microphone (for the above 300 measurement)
          > > in stages until you get something that is fairly stable
          > > with respect to vertical position. Then correct that.
          > >
          > > A line source--or a quasi line source(the Soundlines
          > > are not a true line source at 300 Hz say---too short
          > > a quasi ribbon for that)--has to be corrected
          > > carefully. You definitely do not want to "correct"
          > > the zigs and zags in response that arise because
          > > of the finite length of the line source.
          > >
          > > Actually the best results would probably be
          > > to smooth out the 1/3 octave RTA at the listening
          > > position and retain its natural roll off in the
          > > extreme top. Of course this is actually the
          > > best thing to do in most cases, even though
          > > DSP people hate to admit this. Fix spatially
          > > stable effects, and that is all.
          > >
          > > REG
          > >
          > > __
          > >
          >




          --
          http://www.alanjordan.org
        • Edward
          Hi Alan Thanks for your listening impressions of the Soundlines. Why do you need two pairs of speakers? Why, for four-channel surround. You can even liven
          Message 4 of 12 , Feb 23, 2013
          • 0 Attachment
            Hi Alan

            Thanks for your listening impressions of the Soundlines. Why do you need two pairs of speakers? Why, for four-channel surround. You can even liven things up by exchanging rears for fronts every so often.

            Edward



            --- In regsaudioforum@yahoogroups.com, Alan Jordan <aljordan@...> wrote:
            >
            > >
            > At this point I'll most likely be keeping both pairs. If my wife asks me
            > what I need with two pair of speakers, I'll ask her what she needs with
            > three horses, and all will be well.
            >
            > Alan
            >
          • Robert
            OK so here is my (partial--memory has faded somewhat) report on the top end of the Soundlines First an apology: Sorry but I do not seem to have handy a copy of
            Message 5 of 12 , Feb 23, 2013
            • 0 Attachment
              OK so here is my (partial--memory has faded somewhat) report
              on the top end of the Soundlines

              First an apology:
              Sorry but I do not seem to have handy a copy of my measurements and at this remove I cannot remember exactly what the measurements looked like. I also cannot recall any observations on this outside what is written in the review—it has been a long time. In the review, I describe the speaker as very flat—but this may have been a matter of being flat across the midrange and lower to mid treble , which is where timbre resides and which I would tend to regard as more important. The extreme top really affects primarily "air" and the character of things like high percussion(eg cymbals) and as it happens trumpets at fairly close range. It does have an effect but the effect is not central to the sound of music for most people—those frequencies tend to dry up in concerts and no one seems to mind much! I had both measurement and listening impressions on this at the time—but both seem to have faded into the mists of time. I may have decided not to make any kind of deal about the issue because in the context of the speaker being so good overall, I did not want to rain on the parade. I was pushing the thing as a big bargain! --which I still believe it was. I apologize for not remembering exactly what I heard, measured , and thought in terms of what to write, but a lot of speakers have gone by since!

              Quasi ribbons that run down pretty far do tend not to quite make it to the top of the top octave at full level(cf Bohlender Graebener Radia measurements in Sphile). This is how come Magnepan starting using a (true) ribbon tweeter—to dubious effect I think on account of integration problems but they did get full extension. BG has gone to a compound unit of some kind I believe for the same reason. Apogees also rolled the high treble down pretty hard—cf
              www.apogeespeakers.com/reviews/the_flat_response_stereophile_review.htm
              This kind of goes with the territory for this type of driver. I may have decided not to mention it in the review because I took it as usual in that type of speaker. Again I cannot really remember!

              I suppose the spirit of the question is whether your pair is somehow defective. If the two drivers match, most likely not. One might think about looking at a time windowed measurement rather than a steady state one—even if the anechoic direct arrival is flat, the room sound is almost sure to nosedive from directivity considerations.

              Note that one should probably do a time windowed measurement at distance rather than a close up measurement where odd interference effects might arise.

              If you feel that the sound is short on "air" and that you are not getting what you think you should from cymbals, you could latch on to some "super tweeters" somewhere. But if you are happy, why worry?
              REG

              --- In regsaudioforum@yahoogroups.com, Alan Jordan <aljordan@...> wrote:
              >
              > Hi Edward,
              >
              > Overall they sound quite good. In fact, for the price, I feel like I've
              > won a small lottery. The bass needs some EQ, as well as a little bit
              > around the 1 kHz region, but otherwise they need less fussing than my other
              > speakers for proper tonal balance. The bass doesn't go as deep as my other
              > speakers (which are solid down to 25 Hz), but that is not noticeable on
              > many recordings. The mid and high frequencies are very smooth and open
              > sounding. For instance, I was listening to a recording of only a harp and
              > a violin just now, and the sound was so luscious I began looking around for
              > the angel and cherubs.
              >
              > They are really quite a treat on large scale symphonic music, in that they
              > are very "open" sounding with very good presence. On some recordings the
              > soundstage effects regarding depth seems quite a trick: definitely the
              > largest front to back spread I've ever heard in any system, even very
              > expensive systems in big rooms at high end audio shops. The speakers are
              > holographic in that sense.
              >
              > Compared to my other speakers, on some recordings the individual
              > instruments can sound a bit ephemeral - less solid. Some of the images
              > tend to float in space, well above the plane of my ear height, and have a
              > bit less bite than that of my box speakers. I don't know if this is caused
              > by the dipole bounce off the back wall or not. I have the speakers about 8
              > feet out from the wall behind them, and some foam type traps on the back
              > wall, but I don't have anywhere near the entire back wall damped like some
              > members here seem to do with their dipole speakers.
              >
              > So overall they have a quite different presentation that benefits some
              > recordings but can sometimes detract from other recordings. Tonally they
              > sound good.
              >
              > At this point I'll most likely be keeping both pairs. If my wife asks me
              > what I need with two pair of speakers, I'll ask her what she needs with
              > three horses, and all will be well.
              >
              > Alan
              >
              > On Sat, Feb 23, 2013 at 3:33 PM, Edward <Edward_Wu@...> wrote:
              >
              > > **
              > >
              > >
              > > Hi Alan
              > >
              > > While we are waiting for Robert to take up your question below, how do the
              > > Soundlines sound so far?
              > >
              > > Best
              > > Edward
              > >
              > >
              > > --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
              > > >
              > > > Hi Robert,
              > > >
              > > > The response of the soundline speakers (at the listening position) is
              > > > fairly easy to fix with 1/3 octave EQ. Still there are a couple of
              > > > anomalies I would like to bring your attention that are stable over
              > > space,
              > > > are shown in both speakers, so seem to be an issue of the panels. Maybe
              > > > you can let me know if they are normal and expected.
              > > >
              > > > First, there is a 3 dB dip about 1/3 octave in width centered at around
              > > 10
              > > > kHz. It looks like a very smooth swoop in response.
              > > >
              > > > Second, you mentioned not messing with the natural roll-off of the
              > > extreme
              > > > top end. The response of the panel takes a dive starting about 13 or 14
              > > > kHz and is about 13 dB down at 20 kHz. This is the same whether measured
              > > > at 1 meter or three meters on axis. I know its been almost a decade ago,
              > > > but do you recall similar behavior in the pair you measured?
              > > >
              > > > Thanks,
              > > > Alan
              > > >
              > > > On Wed, Feb 20, 2013 at 7:35 PM, Robert wrote:
              > > >
              > > > > **
              > >
              > > > >
              > > > >
              > > > > Lots of words on this, but somehow
              > > > > the essential point is (to my eyes)
              > > > > still not made all that clear:
              > > > > A line source measured up close has
              > > > > a detailed response that is highly dependent
              > > > > on vertical position.
              > > > > Overall, in listening terms, line sources
              > > > > are not so sensitive to height. But the microstructure
              > > > > is so sensitive.
              > > > > DO NOT CORRECT THE MICROSTRUCTURE of a close
              > > > > up measurement. This will make a rather
              > > > > uncolored sounding speaker into a colored
              > > > > one.
              > > > >
              > > > > WIth the Holm, you have the option of backing up.
              > > > > Back off the microphone (for the above 300 measurement)
              > > > > in stages until you get something that is fairly stable
              > > > > with respect to vertical position. Then correct that.
              > > > >
              > > > > A line source--or a quasi line source(the Soundlines
              > > > > are not a true line source at 300 Hz say---too short
              > > > > a quasi ribbon for that)--has to be corrected
              > > > > carefully. You definitely do not want to "correct"
              > > > > the zigs and zags in response that arise because
              > > > > of the finite length of the line source.
              > > > >
              > > > > Actually the best results would probably be
              > > > > to smooth out the 1/3 octave RTA at the listening
              > > > > position and retain its natural roll off in the
              > > > > extreme top. Of course this is actually the
              > > > > best thing to do in most cases, even though
              > > > > DSP people hate to admit this. Fix spatially
              > > > > stable effects, and that is all.
              > > > >
              > > > > REG
              > > > >
              > > > > __
              > > > >
              > > >
              > >
              > >
              > >
              >
              >
              >
              > --
              > http://www.alanjordan.org
              >
            • Alan Jordan
              Hi Robert, Thank you for answering and for the links you included. No apologies necessary; I didn t really expect you to remember something from something so
              Message 6 of 12 , Feb 24, 2013
              • 0 Attachment
                Hi Robert,

                Thank you for answering and for the links you included.  No apologies necessary; I didn't really expect you to remember something from something so long ago.  I did a time windowed measurement at the listening position, as you suggested, which in my room is about 8 feet away from each speaker.  Even at 1/12 octave smoothing, they measure +-3 dB at the listening position from 300 Hz up to 8 kHz, and most of that range is actually +- 2 dB.  That is pretty tremendous without EQ or correction, compared to other speakers I've tried in my room.  I am using the Holm for room correction up to 300 Hz, and the EQ feature of the Holm to flatten out a broad shallow dip in the midrange.  The results sound excellent.  No further speaker correction or EQ is needed.  I definitely don't need super tweeters.

                Alan

                  
                On Sat, Feb 23, 2013 at 7:17 PM, Robert <regtas43@...> wrote:
                 

                OK so here is my (partial--memory has faded somewhat) report
                on the top end of the Soundlines

                First an apology:
                Sorry but I do not seem to have handy a copy of my measurements and at this remove I cannot remember exactly what the measurements looked like. I also cannot recall any observations on this outside what is written in the review—it has been a long time. In the review, I describe the speaker as very flat—but this may have been a matter of being flat across the midrange and lower to mid treble , which is where timbre resides and which I would tend to regard as more important. The extreme top really affects primarily "air" and the character of things like high percussion(eg cymbals) and as it happens trumpets at fairly close range. It does have an effect but the effect is not central to the sound of music for most people—those frequencies tend to dry up in concerts and no one seems to mind much! I had both measurement and listening impressions on this at the time—but both seem to have faded into the mists of time. I may have decided not to make any kind of deal about the issue because in the context of the speaker being so good overall, I did not want to rain on the parade. I was pushing the thing as a big bargain! --which I still believe it was. I apologize for not remembering exactly what I heard, measured , and thought in terms of what to write, but a lot of speakers have gone by since!

                Quasi ribbons that run down pretty far do tend not to quite make it to the top of the top octave at full level(cf Bohlender Graebener Radia measurements in Sphile). This is how come Magnepan starting using a (true) ribbon tweeter—to dubious effect I think on account of integration problems but they did get full extension. BG has gone to a compound unit of some kind I believe for the same reason. Apogees also rolled the high treble down pretty hard—cf
                www.apogeespeakers.com/reviews/the_flat_response_stereophile_review.htm
                This kind of goes with the territory for this type of driver. I may have decided not to mention it in the review because I took it as usual in that type of speaker. Again I cannot really remember!

                I suppose the spirit of the question is whether your pair is somehow defective. If the two drivers match, most likely not. One might think about looking at a time windowed measurement rather than a steady state one—even if the anechoic direct arrival is flat, the room sound is almost sure to nosedive from directivity considerations.

                Note that one should probably do a time windowed measurement at distance rather than a close up measurement where odd interference effects might arise.

                If you feel that the sound is short on "air" and that you are not getting what you think you should from cymbals, you could latch on to some "super tweeters" somewhere. But if you are happy, why worry?
                REG



                --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
                >
                > Hi Edward,
                >
                > Overall they sound quite good. In fact, for the price, I feel like I've
                > won a small lottery. The bass needs some EQ, as well as a little bit
                > around the 1 kHz region, but otherwise they need less fussing than my other
                > speakers for proper tonal balance. The bass doesn't go as deep as my other
                > speakers (which are solid down to 25 Hz), but that is not noticeable on
                > many recordings. The mid and high frequencies are very smooth and open
                > sounding. For instance, I was listening to a recording of only a harp and
                > a violin just now, and the sound was so luscious I began looking around for
                > the angel and cherubs.
                >
                > They are really quite a treat on large scale symphonic music, in that they
                > are very "open" sounding with very good presence. On some recordings the
                > soundstage effects regarding depth seems quite a trick: definitely the
                > largest front to back spread I've ever heard in any system, even very
                > expensive systems in big rooms at high end audio shops. The speakers are
                > holographic in that sense.
                >
                > Compared to my other speakers, on some recordings the individual
                > instruments can sound a bit ephemeral - less solid. Some of the images
                > tend to float in space, well above the plane of my ear height, and have a
                > bit less bite than that of my box speakers. I don't know if this is caused
                > by the dipole bounce off the back wall or not. I have the speakers about 8
                > feet out from the wall behind them, and some foam type traps on the back
                > wall, but I don't have anywhere near the entire back wall damped like some
                > members here seem to do with their dipole speakers.
                >
                > So overall they have a quite different presentation that benefits some
                > recordings but can sometimes detract from other recordings. Tonally they
                > sound good.
                >
                > At this point I'll most likely be keeping both pairs. If my wife asks me
                > what I need with two pair of speakers, I'll ask her what she needs with
                > three horses, and all will be well.
                >
                > Alan
                >
                > On Sat, Feb 23, 2013 at 3:33 PM, Edward wrote:
                >
                > > **

                > >
                > >
                > > Hi Alan
                > >
                > > While we are waiting for Robert to take up your question below, how do the
                > > Soundlines sound so far?
                > >
                > > Best
                > > Edward
                > >
                > >
                > > --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
                > > >
                > > > Hi Robert,
                > > >
                > > > The response of the soundline speakers (at the listening position) is
                > > > fairly easy to fix with 1/3 octave EQ. Still there are a couple of
                > > > anomalies I would like to bring your attention that are stable over
                > > space,
                > > > are shown in both speakers, so seem to be an issue of the panels. Maybe
                > > > you can let me know if they are normal and expected.
                > > >
                > > > First, there is a 3 dB dip about 1/3 octave in width centered at around
                > > 10
                > > > kHz. It looks like a very smooth swoop in response.
                > > >
                > > > Second, you mentioned not messing with the natural roll-off of the
                > > extreme
                > > > top end. The response of the panel takes a dive starting about 13 or 14
                > > > kHz and is about 13 dB down at 20 kHz. This is the same whether measured
                > > > at 1 meter or three meters on axis. I know its been almost a decade ago,
                > > > but do you recall similar behavior in the pair you measured?
                > > >
                > > > Thanks,
                > > > Alan
                > > >
                > > > On Wed, Feb 20, 2013 at 7:35 PM, Robert wrote:
                > > >
                > > > > **
                > >
                > > > >
                > > > >
                > > > > Lots of words on this, but somehow
                > > > > the essential point is (to my eyes)
                > > > > still not made all that clear:
                > > > > A line source measured up close has
                > > > > a detailed response that is highly dependent
                > > > > on vertical position.
                > > > > Overall, in listening terms, line sources
                > > > > are not so sensitive to height. But the microstructure
                > > > > is so sensitive.
                > > > > DO NOT CORRECT THE MICROSTRUCTURE of a close
                > > > > up measurement. This will make a rather
                > > > > uncolored sounding speaker into a colored
                > > > > one.
                > > > >
                > > > > WIth the Holm, you have the option of backing up.
                > > > > Back off the microphone (for the above 300 measurement)
                > > > > in stages until you get something that is fairly stable
                > > > > with respect to vertical position. Then correct that.
                > > > >
                > > > > A line source--or a quasi line source(the Soundlines
                > > > > are not a true line source at 300 Hz say---too short
                > > > > a quasi ribbon for that)--has to be corrected
                > > > > carefully. You definitely do not want to "correct"
                > > > > the zigs and zags in response that arise because
                > > > > of the finite length of the line source.
                > > > >
                > > > > Actually the best results would probably be
                > > > > to smooth out the 1/3 octave RTA at the listening
                > > > > position and retain its natural roll off in the
                > > > > extreme top. Of course this is actually the
                > > > > best thing to do in most cases, even though
                > > > > DSP people hate to admit this. Fix spatially
                > > > > stable effects, and that is all.
                > > > >

              • Alan Jordan
                I learned something interesting today regarding the diving high frequency response I reported in my measurement of the Soundline speakers. The manufacturer of
                Message 7 of 12 , Feb 25, 2013
                • 0 Attachment
                  I learned something interesting today regarding the diving high
                  frequency response I reported in my measurement of the Soundline
                  speakers. The manufacturer of the panel used in the speaker
                  recommends a minimum listening distance of 10 feet for this specific
                  model, in order to avoid high frequency losses. My listening room
                  will support such distances, but I never thought to try such a
                  distance. I'll try repositioning tonight.

                  Alan

                  On Sun, Feb 24, 2013 at 4:04 PM, Alan Jordan <aljordan@...> wrote:
                  > Hi Robert,
                  >
                  > Thank you for answering and for the links you included. No apologies
                  > necessary; I didn't really expect you to remember something from something
                  > so long ago. I did a time windowed measurement at the listening position,
                  > as you suggested, which in my room is about 8 feet away from each speaker.
                  > Even at 1/12 octave smoothing, they measure +-3 dB at the listening position
                  > from 300 Hz up to 8 kHz, and most of that range is actually +- 2 dB. That
                  > is pretty tremendous without EQ or correction, compared to other speakers
                  > I've tried in my room. I am using the Holm for room correction up to 300
                  > Hz, and the EQ feature of the Holm to flatten out a broad shallow dip in the
                  > midrange. The results sound excellent. No further speaker correction or EQ
                  > is needed. I definitely don't need super tweeters.
                  >
                  > Alan
                  >
                  >
                  > On Sat, Feb 23, 2013 at 7:17 PM, Robert <regtas43@...> wrote:
                  >>
                  >>
                  >>
                  >> OK so here is my (partial--memory has faded somewhat) report
                  >> on the top end of the Soundlines
                  >>
                  >> First an apology:
                  >> Sorry but I do not seem to have handy a copy of my measurements and at
                  >> this remove I cannot remember exactly what the measurements looked like. I
                  >> also cannot recall any observations on this outside what is written in the
                  >> review—it has been a long time. In the review, I describe the speaker as
                  >> very flat—but this may have been a matter of being flat across the midrange
                  >> and lower to mid treble , which is where timbre resides and which I would
                  >> tend to regard as more important. The extreme top really affects primarily
                  >> "air" and the character of things like high percussion(eg cymbals) and as it
                  >> happens trumpets at fairly close range. It does have an effect but the
                  >> effect is not central to the sound of music for most people—those
                  >> frequencies tend to dry up in concerts and no one seems to mind much! I had
                  >> both measurement and listening impressions on this at the time—but both seem
                  >> to have faded into the mists of time. I may have decided not to make any
                  >> kind of deal about the issue because in the context of the speaker being so
                  >> good overall, I did not want to rain on the parade. I was pushing the thing
                  >> as a big bargain! --which I still believe it was. I apologize for not
                  >> remembering exactly what I heard, measured , and thought in terms of what to
                  >> write, but a lot of speakers have gone by since!
                  >>
                  >> Quasi ribbons that run down pretty far do tend not to quite make it to the
                  >> top of the top octave at full level(cf Bohlender Graebener Radia
                  >> measurements in Sphile). This is how come Magnepan starting using a (true)
                  >> ribbon tweeter—to dubious effect I think on account of integration problems
                  >> but they did get full extension. BG has gone to a compound unit of some kind
                  >> I believe for the same reason. Apogees also rolled the high treble down
                  >> pretty hard—cf
                  >> www.apogeespeakers.com/reviews/the_flat_response_stereophile_review.htm
                  >> This kind of goes with the territory for this type of driver. I may have
                  >> decided not to mention it in the review because I took it as usual in that
                  >> type of speaker. Again I cannot really remember!
                  >>
                  >> I suppose the spirit of the question is whether your pair is somehow
                  >> defective. If the two drivers match, most likely not. One might think about
                  >> looking at a time windowed measurement rather than a steady state one—even
                  >> if the anechoic direct arrival is flat, the room sound is almost sure to
                  >> nosedive from directivity considerations.
                  >>
                  >> Note that one should probably do a time windowed measurement at distance
                  >> rather than a close up measurement where odd interference effects might
                  >> arise.
                  >>
                  >> If you feel that the sound is short on "air" and that you are not getting
                  >> what you think you should from cymbals, you could latch on to some "super
                  >> tweeters" somewhere. But if you are happy, why worry?
                  >> REG
                  >>
                  >>
                  >>
                  >> --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
                  >> >
                  >> > Hi Edward,
                  >> >
                  >> > Overall they sound quite good. In fact, for the price, I feel like I've
                  >> > won a small lottery. The bass needs some EQ, as well as a little bit
                  >> > around the 1 kHz region, but otherwise they need less fussing than my
                  >> > other
                  >> > speakers for proper tonal balance. The bass doesn't go as deep as my
                  >> > other
                  >> > speakers (which are solid down to 25 Hz), but that is not noticeable on
                  >> > many recordings. The mid and high frequencies are very smooth and open
                  >> > sounding. For instance, I was listening to a recording of only a harp
                  >> > and
                  >> > a violin just now, and the sound was so luscious I began looking around
                  >> > for
                  >> > the angel and cherubs.
                  >> >
                  >> > They are really quite a treat on large scale symphonic music, in that
                  >> > they
                  >> > are very "open" sounding with very good presence. On some recordings the
                  >> > soundstage effects regarding depth seems quite a trick: definitely the
                  >> > largest front to back spread I've ever heard in any system, even very
                  >> > expensive systems in big rooms at high end audio shops. The speakers are
                  >> > holographic in that sense.
                  >> >
                  >> > Compared to my other speakers, on some recordings the individual
                  >> > instruments can sound a bit ephemeral - less solid. Some of the images
                  >> > tend to float in space, well above the plane of my ear height, and have
                  >> > a
                  >> > bit less bite than that of my box speakers. I don't know if this is
                  >> > caused
                  >> > by the dipole bounce off the back wall or not. I have the speakers about
                  >> > 8
                  >> > feet out from the wall behind them, and some foam type traps on the back
                  >> > wall, but I don't have anywhere near the entire back wall damped like
                  >> > some
                  >> > members here seem to do with their dipole speakers.
                  >> >
                  >> > So overall they have a quite different presentation that benefits some
                  >> > recordings but can sometimes detract from other recordings. Tonally they
                  >> > sound good.
                  >> >
                  >> > At this point I'll most likely be keeping both pairs. If my wife asks me
                  >> > what I need with two pair of speakers, I'll ask her what she needs with
                  >> > three horses, and all will be well.
                  >> >
                  >> > Alan
                  >> >
                  >> > On Sat, Feb 23, 2013 at 3:33 PM, Edward wrote:
                  >> >
                  >> > > **
                  >>
                  >> > >
                  >> > >
                  >> > > Hi Alan
                  >> > >
                  >> > > While we are waiting for Robert to take up your question below, how do
                  >> > > the
                  >> > > Soundlines sound so far?
                  >> > >
                  >> > > Best
                  >> > > Edward
                  >> > >
                  >> > >
                  >> > > --- In regsaudioforum@yahoogroups.com, Alan Jordan wrote:
                  >> > > >
                  >> > > > Hi Robert,
                  >> > > >
                  >> > > > The response of the soundline speakers (at the listening position)
                  >> > > > is
                  >> > > > fairly easy to fix with 1/3 octave EQ. Still there are a couple of
                  >> > > > anomalies I would like to bring your attention that are stable over
                  >> > > space,
                  >> > > > are shown in both speakers, so seem to be an issue of the panels.
                  >> > > > Maybe
                  >> > > > you can let me know if they are normal and expected.
                  >> > > >
                  >> > > > First, there is a 3 dB dip about 1/3 octave in width centered at
                  >> > > > around
                  >> > > 10
                  >> > > > kHz. It looks like a very smooth swoop in response.
                  >> > > >
                  >> > > > Second, you mentioned not messing with the natural roll-off of the
                  >> > > extreme
                  >> > > > top end. The response of the panel takes a dive starting about 13 or
                  >> > > > 14
                  >> > > > kHz and is about 13 dB down at 20 kHz. This is the same whether
                  >> > > > measured
                  >> > > > at 1 meter or three meters on axis. I know its been almost a decade
                  >> > > > ago,
                  >> > > > but do you recall similar behavior in the pair you measured?
                  >> > > >
                  >> > > > Thanks,
                  >> > > > Alan
                  >> > > >
                  >> > > > On Wed, Feb 20, 2013 at 7:35 PM, Robert wrote:
                  >> > > >
                  >> > > > > **
                  >> > >
                  >> > > > >
                  >> > > > >
                  >> > > > > Lots of words on this, but somehow
                  >> > > > > the essential point is (to my eyes)
                  >> > > > > still not made all that clear:
                  >> > > > > A line source measured up close has
                  >> > > > > a detailed response that is highly dependent
                  >> > > > > on vertical position.
                  >> > > > > Overall, in listening terms, line sources
                  >> > > > > are not so sensitive to height. But the microstructure
                  >> > > > > is so sensitive.
                  >> > > > > DO NOT CORRECT THE MICROSTRUCTURE of a close
                  >> > > > > up measurement. This will make a rather
                  >> > > > > uncolored sounding speaker into a colored
                  >> > > > > one.
                  >> > > > >
                  >> > > > > WIth the Holm, you have the option of backing up.
                  >> > > > > Back off the microphone (for the above 300 measurement)
                  >> > > > > in stages until you get something that is fairly stable
                  >> > > > > with respect to vertical position. Then correct that.
                  >> > > > >
                  >> > > > > A line source--or a quasi line source(the Soundlines
                  >> > > > > are not a true line source at 300 Hz say---too short
                  >> > > > > a quasi ribbon for that)--has to be corrected
                  >> > > > > carefully. You definitely do not want to "correct"
                  >> > > > > the zigs and zags in response that arise because
                  >> > > > > of the finite length of the line source.
                  >> > > > >
                  >> > > > > Actually the best results would probably be
                  >> > > > > to smooth out the 1/3 octave RTA at the listening
                  >> > > > > position and retain its natural roll off in the
                  >> > > > > extreme top. Of course this is actually the
                  >> > > > > best thing to do in most cases, even though
                  >> > > > > DSP people hate to admit this. Fix spatially
                  >> > > > > stable effects, and that is all.
                • Kim Rochat
                  ... The driver in your Soundline is a Bohlender Graebener RD50. I ve been looking at the BG spec sheet for the various models of drivers and it says: The RD
                  Message 8 of 12 , Feb 25, 2013
                  • 0 Attachment
                    At 03:37 PM 2/25/2013, you wrote:
                    >I learned something interesting today regarding the diving high
                    >frequency response I reported in my measurement of the Soundline
                    >speakers. The manufacturer of the panel used in the speaker
                    >recommends a minimum listening distance of 10 feet for this specific
                    >model, in order to avoid high frequency losses. My listening room
                    >will support such distances, but I never thought to try such a
                    >distance. I'll try repositioning tonight.
                    >
                    >Alan

                    The driver in your Soundline is a Bohlender Graebener RD50.
                    I've been looking at the BG spec sheet for the various models of
                    drivers and it says:

                    "The RD drivers are essentially line-source radiators, hence there is a certain
                    relation between the driver length and listening distance, as
                    outlined the table
                    below. Smaller listening distances may result in a somewhat subjective
                    perception of decreased output at the highest frequencies. This
                    limitation can be
                    overcome in smaller systems with a complementing supertweeter."

                    "Minimum recommended listening distance
                    Model RD75 (75" tall - 15 ft.)
                    Model RD50 (50" tall - 10 ft - this is the model used in the Soundline)
                    Model RD40 (40" tall - 8 ft)"

                    I've been listening to my Vandersteens near-field - about 4' and
                    they're well away from the side and back walls.
                    I've been toying with the idea of replacing the Vandersteens with a
                    pair of BG drivers and using them with my TacT corner woofers.
                    But this listening distance thing has me confused. All three models
                    list the same frequency response. I'm thinking that the 40" model
                    (which is also the cheapest) would be the one to get. Assuming it's
                    mounted vertically (not tilted) and I'm listening on-axis, both
                    horizontally and
                    vertically - is there an advantage to using the taller drivers? Also,
                    can the treble can be equalized to whatever I want if I'm listening
                    closer than the recommended distance or is there some characteristic
                    of the ribbon that inhibits treble equalization?

                    Thanks,
                    Kim
                  • Alan Jordan
                    Hi Kim, Look a little further down, in that same table, at the power handling specification. It appears that the only difference in specifications as you go
                    Message 9 of 12 , Feb 25, 2013
                    • 0 Attachment
                      Hi Kim,

                      Look a little further down, in that same table, at the power handling specification.  It appears that the only difference in specifications as you go into the larger ribbons, is greater power handling ability. which I suppose translates into greater max SPL given the same crossover point.  I don't listen particularly loudly, so that difference wouldn't concern me.

                      I did reposition the speakers and listening chair this evening, so that I am a little further than ten feet away, as apposed to the 8 feet I was previously.  There are a number of rather noticeable effects,

                      - Initial attack on piano keys, cymbals, drums and steel drums is a
                      lot more prevalent.
                      - The ephemeral quality that I had earlier reported on some instruments is completely gone.
                      - The higher-than--the-head image height issue that I reported on some
                      instruments disappears and the entire listening height comes back down
                      to normal levels.
                      - More high frequencies energy.
                      - Less low frequency energy.
                      - Better tonal balance across the board.

                      I am thinking the the high / low frequency energy balance comes into play because of the traditional driver ported woofer that the planar is mated to.  Given that the planar driver loses 3 dB of SPL as compared to the 6 dB of the cone as distance doubles, there must have been some specific listening range that brings the two into balance.  Most of the things I pointed out shouldn't matter if you are going to DSP the system.  

                      But...

                      The reason I even started looking into this issue was that as I was listening last night, I noticed rather small movements of my head were having rather large results in treble energy, and I thought that was not supposed to be an issue with a narrow ribbon that has good dispersion.  When I moved the listening position back, that issue also completely disappeared.  I think that ephemeral quality I was referring to might have something to do with the relation of the height line source and seating distance.  Since you mentioned the Tacts are "corner woofers", I imagine you are not mounting the panel on top of the woofer -as is the case of the Soundlines.  Maybe you have the ability to mount the ribbon at a lower height, which might avoid some of the issues with treble energy stability, image height, and "ephemeralness".  All of the other frequency balance issues should go away with DSP.  

                      Of course, I don't know the science of all of this, and the reported differences might be due to something completely different.  I can say that the sound of the ribbons don't need any EQ once I've moved the listening position back.  It might be due to distance needed for the ribbon to integrate with itself, or to integrate with the bass woofer.

                      I would be very interested in your results if you do buy the ribbon and try a home grown speaker.  Also note that the manufacturer recommends a notch filter between 5 and 6 kHz to deal with the resonance of the panel.  I would like to know how wide and deep that filter should be, as I was considering an experiment bypassing the passive crossover and using the Holm unit's digital crossover and EQ capabilities instead.

                      Maybe Robert can answer your question regarding an inherent characteristic of the quasi-ribbon that inhibits treble EQ.

                      Thanks,
                      Alan

                      On Mon, Feb 25, 2013 at 7:18 PM, Kim Rochat <krochat@...> wrote:
                       

                      At 03:37 PM 2/25/2013, you wrote:
                      >I learned something interesting today regarding the diving high
                      >frequency response I reported in my measurement of the Soundline
                      >speakers. The manufacturer of the panel used in the speaker
                      >recommends a minimum listening distance of 10 feet for this specific
                      >model, in order to avoid high frequency losses. My listening room
                      >will support such distances, but I never thought to try such a
                      >distance. I'll try repositioning tonight.
                      >
                      >Alan

                      The driver in your Soundline is a Bohlender Graebener RD50.
                      I've been looking at the BG spec sheet for the various models of
                      drivers and it says:

                      "The RD drivers are essentially line-source radiators, hence there is a certain
                      relation between the driver length and listening distance, as
                      outlined the table
                      below. Smaller listening distances may result in a somewhat subjective
                      perception of decreased output at the highest frequencies. This
                      limitation can be
                      overcome in smaller systems with a complementing supertweeter."

                      "Minimum recommended listening distance
                      Model RD75 (75" tall - 15 ft.)
                      Model RD50 (50" tall - 10 ft - this is the model used in the Soundline)
                      Model RD40 (40" tall - 8 ft)"

                      I've been listening to my Vandersteens near-field - about 4' and
                      they're well away from the side and back walls.
                      I've been toying with the idea of replacing the Vandersteens with a
                      pair of BG drivers and using them with my TacT corner woofers.
                      But this listening distance thing has me confused. All three models
                      list the same frequency response. I'm thinking that the 40" model
                      (which is also the cheapest) would be the one to get. Assuming it's
                      mounted vertically (not tilted) and I'm listening on-axis, both
                      horizontally and
                      vertically - is there an advantage to using the taller drivers? Also,
                      can the treble can be equalized to whatever I want if I'm listening
                      closer than the recommended distance or is there some characteristic
                      of the ribbon that inhibits treble equalization?

                      Thanks,
                      Kim


                    • Kim Rochat
                      Alan, Thanks for the comprehensive response. From your comments it seems like I shouldn t try to use the BG drivers near-field if moving from 8 to 10+ ft made
                      Message 10 of 12 , Feb 25, 2013
                      • 0 Attachment
                        Alan,

                        Thanks for the comprehensive response. From your comments it seems like I shouldn't try to use the BG drivers near-field if moving from 8 to 10+ ft made a significant improvement for you.

                        I was going to mount them in a wooden frames, height adjusted to center my ear on the driver. Crossover to the corner woofers would
                        be around 325Hz, with crossover, delay, and equalization done using Acourate.

                        I don't need much loudness - I'm trying to protect my aging ears, so that's not a factor.
                        I will have to rethink placement. It seems that the 40" driver would need at least 8 feet in front + probably 7 feet behind

                        Thanks again,
                        Kim

                        At 05:24 PM 2/25/2013, you wrote:
                         

                        Hi Kim,

                        Look a little further down, in that same table, at the power handling specification.  It appears that the only difference in specifications as you go into the larger ribbons, is greater power handling ability. which I suppose translates into greater max SPL given the same crossover point.  I don't listen particularly loudly, so that difference wouldn't concern me.

                        I did reposition the speakers and listening chair this evening, so that I am a little further than ten feet away, as apposed to the 8 feet I was previously.  There are a number of rather noticeable effects,

                        - Initial attack on piano keys, cymbals, drums and steel drums is a
                        lot more prevalent.
                        - The ephemeral quality that I had earlier reported on some instruments is completely gone.
                        - The higher-than--the-head image height issue that I reported on some
                        instruments disappears and the entire listening height comes back down
                        to normal levels.
                        - More high frequencies energy.
                        - Less low frequency energy.
                        - Better tonal balance across the board.

                        I am thinking the the high / low frequency energy balance comes into play because of the traditional driver ported woofer that the planar is mated to.  Given that the planar driver loses 3 dB of SPL as compared to the 6 dB of the cone as distance doubles, there must have been some specific listening range that brings the two into balance.  Most of the things I pointed out shouldn't matter if you are going to DSP the system. 

                        But...

                        The reason I even started looking into this issue was that as I was listening last night, I noticed rather small movements of my head were having rather large results in treble energy, and I thought that was not supposed to be an issue with a narrow ribbon that has good dispersion.  When I moved the listening position back, that issue also completely disappeared.  I think that ephemeral quality I was referring to might have something to do with the relation of the height line source and seating distance.  Since you mentioned the Tacts are "corner woofers", I imagine you are not mounting the panel on top of the woofer -as is the case of the Soundlines.  Maybe you have the ability to mount the ribbon at a lower height, which might avoid some of the issues with treble energy stability, image height, and "ephemeralness".  All of the other frequency balance issues should go away with DSP. 

                        Of course, I don't know the science of all of this, and the reported differences might be due to something completely different.  I can say that the sound of the ribbons don't need any EQ once I've moved the listening position back.  It might be due to distance needed for the ribbon to integrate with itself, or to integrate with the bass woofer.

                        I would be very interested in your results if you do buy the ribbon and try a home grown speaker.  Also note that the manufacturer recommends a notch filter between 5 and 6 kHz to deal with the resonance of the panel.  I would like to know how wide and deep that filter should be, as I was considering an experiment bypassing the passive crossover and using the Holm unit's digital crossover and EQ capabilities instead.

                        Maybe Robert can answer your question regarding an inherent characteristic of the quasi-ribbon that inhibits treble EQ.

                        Thanks,
                        Alan

                        On Mon, Feb 25, 2013 at 7:18 PM, Kim Rochat <krochat@...> wrote:
                         

                        At 03:37 PM 2/25/2013, you wrote:
                        >I learned something interesting today regarding the diving high
                        >frequency response I reported in my measurement of the Soundline
                        >speakers. The manufacturer of the panel used in the speaker
                        >recommends a minimum listening distance of 10 feet for this specific
                        >model, in order to avoid high frequency losses. My listening room
                        >will support such distances, but I never thought to try such a
                        >distance. I'll try repositioning tonight.
                        >
                        >Alan

                        The driver in your Soundline is a Bohlender Graebener RD50.
                        I've been looking at the BG spec sheet for the various models of
                        drivers and it says:

                        "The RD drivers are essentially line-source radiators, hence there is a certain
                        relation between the driver length and listening distance, as
                        outlined the table
                        below. Smaller listening distances may result in a somewhat subjective
                        perception of decreased output at the highest frequencies. This
                        limitation can be
                        overcome in smaller systems with a complementing supertweeter."

                        "Minimum recommended listening distance
                        Model RD75 (75" tall - 15 ft.)
                        Model RD50 (50" tall - 10 ft - this is the model used in the Soundline)
                        Model RD40 (40" tall - 8 ft)"

                        I've been listening to my Vandersteens near-field - about 4' and
                        they're well away from the side and back walls.
                        I've been toying with the idea of replacing the Vandersteens with a
                        pair of BG drivers and using them with my TacT corner woofers.
                        But this listening distance thing has me confused. All three models
                        list the same frequency response. I'm thinking that the 40" model
                        (which is also the cheapest) would be the one to get. Assuming it's
                        mounted vertically (not tilted) and I'm listening on-axis, both
                        horizontally and
                        vertically - is there an advantage to using the taller drivers? Also,
                        can the treble can be equalized to whatever I want if I'm listening
                        closer than the recommended distance or is there some characteristic
                        of the ribbon that inhibits treble equalization?

                        Thanks,
                        Kim


                      • Robert
                        It is definitely true that the frequency response of a partial line source depends on distance. (I mentioned this earlier but perhaps without enough emphasis).
                        Message 11 of 12 , Feb 25, 2013
                        • 0 Attachment
                          It is definitely true that the frequency response
                          of a partial line source depends on distance.
                          (I mentioned this earlier but perhaps without
                          enough emphasis).
                          This is part of the reason that some theoretically
                          inclined people, eg Stanley Lipshitz, object to them.

                          Maybe I can explain(without the mathematics)
                          roughly why the distance matters.
                          Here goes:
                          A point source drops off like 1/distance squared
                          A (true) line source drops off like 1 /distance.
                          Now a finite length line source is partly like
                          a point source at low frequencies. (Imagine a really
                          low frequency --the finite line source will not
                          be at all large relative to the wavelength of the sound
                          so the line source is really acting like a point)
                          But as the wavelength gets shorter(as frequency rises)
                          then the line source really starts to act like a line
                          source.
                          Now you can see why the balance shifts with distance:
                          lower frequencies tend to drop off more like 1/distance squared
                          being more point source like while high frequencies
                          being really like a line source, drop off like a/distance.
                          Hence at larger distance, more highs in proportion to lower down!
                          Hope that makes sense to everybody!

                          REG


                          --- In regsaudioforum@yahoogroups.com, Kim Rochat <krochat@...> wrote:
                          >
                          > Alan,
                          >
                          > Thanks for the comprehensive response. From your
                          > comments it seems like I shouldn't try to use the
                          > BG drivers near-field if moving from 8 to 10+ ft
                          > made a significant improvement for you.
                          >
                          > I was going to mount them in a wooden frames,
                          > height adjusted to center my ear on the driver.
                          > Crossover to the corner woofers would
                          > be around 325Hz, with crossover, delay, and equalization done using Acourate.
                          >
                          > I don't need much loudness - I'm trying to
                          > protect my aging ears, so that's not a factor.
                          > I will have to rethink placement. It seems that
                          > the 40" driver would need at least 8 feet in front + probably 7 feet behind
                          >
                          > Thanks again,
                          > Kim
                          >
                          > At 05:24 PM 2/25/2013, you wrote:
                          > >
                          > >
                          > >Hi Kim,
                          > >
                          > >Look a little further down, in that same table,
                          > >at the power handling specification. It appears
                          > >that the only difference in specifications as
                          > >you go into the larger ribbons, is greater power
                          > >handling ability. which I suppose translates
                          > >into greater max SPL given the same crossover
                          > >point. I don't listen particularly loudly, so
                          > >that difference wouldn't concern me.
                          > >
                          > >I did reposition the speakers and listening
                          > >chair this evening, so that I am a little
                          > >further than ten feet away, as apposed to the 8
                          > >feet I was previously. There are a number of rather noticeable effects,
                          > >
                          > >- Initial attack on piano keys, cymbals, drums and steel drums is a
                          > >lot more prevalent.
                          > >- The ephemeral quality that I had earlier
                          > >reported on some instruments is completely gone.
                          > >- The higher-than--the-head image height issue that I reported on some
                          > >instruments disappears and the entire listening height comes back down
                          > >to normal levels.
                          > >- More high frequencies energy.
                          > >- Less low frequency energy.
                          > >- Better tonal balance across the board.
                          > >
                          > >I am thinking the the high / low frequency
                          > >energy balance comes into play because of the
                          > >traditional driver ported woofer that the planar
                          > >is mated to. Given that the planar driver loses
                          > >3 dB of SPL as compared to the 6 dB of the cone
                          > >as distance doubles, there must have been some
                          > >specific listening range that brings the two
                          > >into balance. Most of the things I pointed out
                          > >shouldn't matter if you are going to DSP the system.
                          > >
                          > >But...
                          > >
                          > >The reason I even started looking into this
                          > >issue was that as I was listening last night, I
                          > >noticed rather small movements of my head were
                          > >having rather large results in treble energy,
                          > >and I thought that was not supposed to be an
                          > >issue with a narrow ribbon that has good
                          > >dispersion. When I moved the listening position
                          > >back, that issue also completely disappeared. I
                          > >think that ephemeral quality I was referring to
                          > >might have something to do with the relation of
                          > >the height line source and seating
                          > >distance. Since you mentioned the Tacts are
                          > >"corner woofers", I imagine you are not mounting
                          > >the panel on top of the woofer -as is the case
                          > >of the Soundlines. Maybe you have the ability
                          > >to mount the ribbon at a lower height, which
                          > >might avoid some of the issues with treble
                          > >energy stability, image height, and
                          > >"ephemeralness". All of the other frequency
                          > >balance issues should go away with DSP.
                          > >
                          > >Of course, I don't know the science of all of
                          > >this, and the reported differences might be due
                          > >to something completely different. I can say
                          > >that the sound of the ribbons don't need any EQ
                          > >once I've moved the listening position back. It
                          > >might be due to distance needed for the ribbon
                          > >to integrate with itself, or to integrate with the bass woofer.
                          > >
                          > >I would be very interested in your results if
                          > >you do buy the ribbon and try a home grown
                          > >speaker. Also note that the manufacturer
                          > >recommends a notch filter between 5 and 6 kHz to
                          > >deal with the resonance of the panel. I would
                          > >like to know how wide and deep that filter
                          > >should be, as I was considering an experiment
                          > >bypassing the passive crossover and using the
                          > >Holm unit's digital crossover and EQ capabilities instead.
                          > >
                          > >Maybe Robert can answer your question regarding
                          > >an inherent characteristic of the quasi-ribbon that inhibits treble EQ.
                          > >
                          > >Thanks,
                          > >Alan
                          > >
                          > >On Mon, Feb 25, 2013 at 7:18 PM, Kim Rochat
                          > ><<mailto:krochat@...>krochat@...> wrote:
                          > >
                          > >
                          > >At 03:37 PM 2/25/2013, you wrote:
                          > > >I learned something interesting today regarding the diving high
                          > > >frequency response I reported in my measurement of the Soundline
                          > > >speakers. The manufacturer of the panel used in the speaker
                          > > >recommends a minimum listening distance of 10 feet for this specific
                          > > >model, in order to avoid high frequency losses. My listening room
                          > > >will support such distances, but I never thought to try such a
                          > > >distance. I'll try repositioning tonight.
                          > > >
                          > > >Alan
                          > >
                          > >The driver in your Soundline is a Bohlender Graebener RD50.
                          > >I've been looking at the BG spec sheet for the various models of
                          > >drivers and it says:
                          > >
                          > >"The RD drivers are essentially line-source
                          > >radiators, hence there is a certain
                          > >relation between the driver length and listening distance, as
                          > >outlined the table
                          > >below. Smaller listening distances may result in a somewhat subjective
                          > >perception of decreased output at the highest frequencies. This
                          > >limitation can be
                          > >overcome in smaller systems with a complementing supertweeter."
                          > >
                          > >"Minimum recommended listening distance
                          > >Model RD75 (75" tall - 15 ft.)
                          > >Model RD50 (50" tall - 10 ft - this is the model used in the Soundline)
                          > >Model RD40 (40" tall - 8 ft)"
                          > >
                          > >I've been listening to my Vandersteens near-field - about 4' and
                          > >they're well away from the side and back walls.
                          > >I've been toying with the idea of replacing the Vandersteens with a
                          > >pair of BG drivers and using them with my TacT corner woofers.
                          > >But this listening distance thing has me confused. All three models
                          > >list the same frequency response. I'm thinking that the 40" model
                          > >(which is also the cheapest) would be the one to get. Assuming it's
                          > >mounted vertically (not tilted) and I'm listening on-axis, both
                          > >horizontally and
                          > >vertically - is there an advantage to using the taller drivers? Also,
                          > >can the treble can be equalized to whatever I want if I'm listening
                          > >closer than the recommended distance or is there some characteristic
                          > >of the ribbon that inhibits treble equalization?
                          > >
                          > >Thanks,
                          > >Kim
                          > >
                          > >
                          > >
                          >
                        Your message has been successfully submitted and would be delivered to recipients shortly.