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Re: [regsaudioforum] Re: Speaker Measurements

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  • Ted Rook
    On 22 Apr 2013 at 17:48, kevindoyle.forum wrote: I m looking into measurement tools now and want a ... have been using happily for the past six years to help
    Message 1 of 22 , Apr 22 3:27 PM
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      On 22 Apr 2013 at 17:48, kevindoyle.forum wrote:

      I'm looking into measurement tools now and want a
      > combination of effective and inexpensive.


      >Some measuring choices for you to consider, these are my measurement tools, which I
      have been using happily for the past six years to help set up my M40s in-room.


      measurement microphone: calibrated NTI "miniSPL" 0.5 inch mic includes battery power (no
      phantom power supply required) and includes internal preamp, no external preamp is
      required, it plugs straight into your sound card input. You will need to source a regular XLR
      mic cable and a converter to go from XLR to soundcard 0.125 inch minijack. Comes in a nice
      hardcase with calibration certificate. Buy online from NTI America $375

      http://shop.nti-audio.com/pd_minispl.cfm


      Real time audio analyzer for windows: TrueRTA software, configured for stereo
      measurement using the windows soundcard inputs and outputs, includes precision signal
      generator, precision real time analyzer, 1/3rd octave version costs $40, the 1/24th octave
      version is $100. This is fully debugged and supported software, I have never had a moment
      of trouble on two different windows machines. It operates in real time all the time, until TM
      mentioned that SynRTA is nearly real time it never occurred to me that there could be
      anything other than real time real-time analyzers, this is a full-time real-time
      real-time-analyzer, instantaneous response time, using traditional sinewave, swept tone, pink
      noise and white noise sources, pink noise being the most useful for room measurements
      since the wished for flat response is a horizontal straight line.

      http://trueaudio.com/rta_abt1.htm


      Both are a pleasure to use.

      Any questions feel free to ask.

      Ted
    • Tom Mallin
      As modern speakers go, Harbeths are odd ducks in terms of frequency balance. Very nicely odd ducks, but odd nonetheless. Look at the Soundstage anechoic
      Message 2 of 22 , Apr 22 7:26 PM
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        As modern speakers go, Harbeths are odd ducks in terms of frequency balance.  Very nicely odd ducks, but odd nonetheless.  Look at the Soundstage anechoic measurements of the Harbeth M30.  I'm sure that everyone who has heard both that speaker and the M40/40.1 will agree that in most any room the larger speaker is even warmer balanced with more midbass.  Compare the amount of response at 100 Hz in those anechoic measurements to the response at 1 kHz.  The 100 Hz response is 4 dB up and the entire response slopes down from bass to treble.  Now look for any other speaker in the Soundstage measurements that has that kind of response.  The only other one that is remotely similar is the Cerwin Vega CLS 215, another REG rave.

        Look at the other measurements I took on the same day with the speakers on the same stand in the same spot in my basement.  Do any other speakers show 100 Hz up 12 dB?  No, far from it.  The woofers of all the speakers were within a couple of inches of the same distance from the floor and walls.  The Harbeth M40.1 obviously has a lot more midbass than any of the other speakers.  The room should affect all those speakers about the same way.

        The generous overall low-end response of Harbeths allows you to cut off the bass peaks with electronic EQ very easily and still not suffer from thin sound because the low frequency dips are still near the reference level of 1 kHz.  That's why they are nicely odd ducks.  You can easily EQ them flatter in the the bass without having to boost the overall bass level to avoid low frequency thinness.  The Harbeths will then will play more loudly with less distortion since both amps and speakers are loafing along.
         


        On Mon, Apr 22, 2013 at 3:45 PM, Robert <regtas43@...> wrote:
         

        You can just tape the mike on with Duc tape.
        Messy but it works. The RTA is fine for in room
        stuff and if you look at how it changes
        with distance you can get a pretty good idea
        of how the speaker would look anechoically.
        A little practice does wonders.

        I don't think TM has the speakers in quite
        optimum positions. The M40 ought to be a lot
        smoother in the bottom and more neutrally
        balanced if it were in the right place.
        And the LS3/6 does not have a dip at 200 Hz
        if you set it up correctly.

        Below around 500 Hz, position is important!
        (and the nature of the room). Look at the differences
        between JAs in room responses (good) and those of
        some of the other writers(not so good) when he
        shows both.

        Below 500 Hz, the speaker does not rule --the
        room rules. The speakers tend to be very similar
        except for absolute extension. Look at the NRC measurements.
        Bass is pretty much predictable and usually quite smooth.
        The Harbeths are a bit warmed up but it is not wild and crazy.
        The wild and crazy effects come from not knowing where
        to put them and/or having a weird room/
        Neither the Harbeth nor any other speaker I can think of
        has a 12 dB rise anywhere.

        Audiophiles find it really hard to give up the idea
        that it is the equipment that is doing what they
        hear and/or measure. Below 500 Hz, not so.
        Measurements in that region are mostly measurements
        of how much you (or your room) messed up. But most
        rooms(TMs is an exception) are not such a big problem.
        If you know where to put the speaker....experimentation
        is the key.

        Don't believe this stuff TM put up in the lower
        frequencies. Not really what the speaker does,
        just what it does in the wrong place, mostly.

        REG

        --- In regsaudioforum@yahoogroups.com, Tom Mallin <tmallin4@...> wrote:
        >
        > Kevin, my photo album contains many other measurements taken of the Harbeth
        > M40 and M40.1 speakers. All the prior measurements were taken in my audio
        > room, which is very symmetrical as rooms go (left and right channels always
        > measure virtually the same before EQ) about 20' x13' x 8' and has all
        > concrete walls and floor. There is drywall and insulation over the wall
        > concrete and carpet and padding on the floor, but no bass trapping. It is
        > my very own concrete basement bunker boom-boom box; it is a very atypical
        > audio room; the walls are very stiff and thus I thus get huge sharp peaks
        > and dips in the bass compared to other rooms.
        >
        > Most of these prior measurements were taken with either this same Liberty
        > Instruments SynRTA software and Girardin microphone (you can tell from the
        > pictures) or my TacT 2.2XP using a calibrated LinearX M31 microphone.
        > There are also a few taken using Liberty Instrument's Praxis.
        >
        > Basically, in my audio room, before EQ, the M40.1 has about an 8 dB high-Q
        > peak centered around 60 - 70 Hz. The M40 peak, seemed twice this large,
        > but REG disputes how I read the graphs. Whatever; there is is a big peak
        > around that frequency in that room with either speaker. Also, there is not
        > much bass from either of those speakers below 50 Hz or so; thus I use
        > subwoofers with those Harbeths. I then use electronic EQ of some sort
        > (I've used Cello Palette Preamp, Z-Systems rdp-1, Rives PARC, Rane DEQ-60L,
        > Audient ASP231, Behringer DEQ2496, TacT RCS 2.2XP, and now soon the
        > DSPeaker DualCore, among others) to flatten the bass. The M40s were
        > unlistenable in this room without electronic EQ; the M40.1s are whumpy but
        > listenable without EQ, at least short term. All other speakers I've used
        > in this room benefited from bass electronic EQ as well, but none have
        > needed it as desperately as the Harbeths.
        >
        > In my newest graphs taken in the home theater area, the M40.1 peak is now
        > 12 dB, but is up higher in frequency and seemingly lower in Q (more spread
        > out). And there is now bass at the 1 kHz reference level down to 25 Hz.
        > That's what I meant when I said this new room "transformed" the M40.1
        > bass. There is still a big peak, but it's now above the midbass thump
        > frequency, is more spread out and seems part of a general rise in low-end
        > response, could energize the power range of an orchestra, plus there is
        > considerable bottom-octave bass.
        >
        > I own and could always use Liberty Instruments Praxis measuring suite,
        > which is a rather sophisticated system. But I've found the free SynRTA
        > software, also by Liberty, to provide very similar results and to be much
        > easier to use for adjusting things since, unlike Praxis, it displays
        > results in real time as you move things, taking only a few seconds to
        > refresh. I do use the Liberty Audio AudPod (which is necessary for Praxis)
        > with SynRTA since part of its function is to act as a microphone preamp.
        > You CAN use the Girardin mike straight into a sound card (I use an M-Audio
        > Transit, as once and still recommended by and available from Liberty
        > Instruments for Praxis), but the levels of test tone noise necessary to
        > make the measurements are then about 20 dB higher and are nasty on the ears
        > that way after a few minutes. With the Audpod/mike preamp, the levels
        > needed are moderate and easy to take for quite awhile.
        >
        > Most good microphones need some sort of microphone preamp between the mike
        > and the sound card since microphone output is usually very low. And the
        > sound cards typically installed in PCs are not very flat over the audio
        > range. Now, some measuring programs promise to correct for the inadequacy
        > of built-in sound cards, buy I have not followed that route. Also, there
        > may well be some fine USB mikes with built in sound cards and preamps out
        > there these days, but I have not investigated them, being content to plod
        > along with the now-rather-antiquated system I use since it seems to produce
        > accurate results. Roger Sanders told me that my measurements of his
        > Sanders 10C speakers were within the best expectable experimental variation
        > compared to the measurements he got using CalTech's anechoic chamber and a
        > very sophisticated measurement rig.
        >
        > The Girardin mike I use (also available from Liberty Instruments) has an
        > RCA jack output, so I use 5 meters of unbalanced Joseph Grado Signature
        > cable (not that the cable matters, but it just happens to not be in use in
        > any of my audio systems and is long enough and quite flexible) on the
        > output to plug it into the AudPod/preamp via some cheapo RCA jack/mini
        > phone plug adapters. The AudPod connects to the M-Audio sound card via
        > cheap short miniplug cables, and then a very short USB cable connects the
        > sound card to a USB input of an old Dell Latitude D600 laptop running XP.
        > I use this laptop for sound measurements since it's old enough to have a
        > 9-pin serial port and can thus easily connect to my TacT RCS 2.2 XP.
        >
        > I also always use a boom-type mike stand with a tripod base for maximum
        > stability and minimum conduction of bass frequencies through the floor into
        > the mike. I have used a number of brands of stand, but find that On-Stage
        > Stands are sturdy, cheap, and easiest to adjust. You want the stand short
        > enough so that the boom arm can angle down and away from the mike when the
        > mike is at measuring height. That puts the mike in as much free space as
        > possible. For a high sitting position, like 48", a 30" high stand is fine.
        > For lower positions, like 38", I use what is sold as a bass drum stand,
        > which is considerably shorter even at maximum extension.
        >
        > Part of the problem with measuring mikes is getting a microphone stand
        > adaptor small enough in diameter to work with the things; most standard
        > mike clips are made for much larger in diameter mikes. The clip that comes
        > with the LinearX fits the mike barrel but is not durable and is a poor fit
        > for standard mike stands; I'm on my third or fourth one--the plastic that
        > holds the mike keeps splitting. The Girardin is ideal in this respect
        > since the mike comes with a sturdy totally integrated clip that is the
        > perfect fit for mike boom threads and has just the right amount of tension
        > in the adjustment to stay put at any given angle yet allow it to be
        > adjusted without applying too much torque.
        >
        > I'd stay away from the Behringer ECM8000 mike. At $50 it's cheap, but it
        > is not calibrated and users have found a plus or minus 5 dB or more
        > variation in the mike's low and high frequency measured response. The
        > LinearX and Girardin both come with calibration files which individually
        > calibrate each serial number of the mikes and even before calibration seem
        > to be better than plus or minus a dB or two from flat over the entire audio
        > range.
        >
        >
        >
        >
        > On Mon, Apr 22, 2013 at 12:48 PM, kevindoyle.forum <doyle.kevin@...>wrote:
        >
        > > **
        > >
        > >
        > > Looks fine on Chrome on OSX. Thank you for sharing your measurements, TM.
        > >
        > > REG alluded to some problems you had with the M40.1's in terms of bass.
        > > What were they? And were they without your various means of EQ? Sorry to
        > > rehash, but I don't rceall the specifics and I'm curious, having recently
        > > seen a long thread on HUG about the bass. It seemed to me something that
        > > could have been easily addressed.
        > >
        > > One other question, the mic you use is USB plugged straight into laptop?
        > > I'm looking into measurement tools now and want a combination of effective
        > > and inexpensive.
        > >
        > > Anyway, thanks again! If this is what you do with a day off, I can't wait
        > > until you retire. Great stuff.
        > >
        > > --- In regsaudioforum@yahoogroups.com, Tom Mallin <tmallin4@> wrote:
        > > >
        > > > I do not have the problem viewing the graphs via Yahoo you have, Laurie,
        > > on
        > > > any of the three desktops and one laptop I've used. The viewing problems
        > > > are probably caused by a combination of your screen size, screen
        > > > resolution, and internet browser. I know that IE10 is causing vertically
        > > > squished images on a number of our office computers; those same images
        > > look
        > > > fine in IE8, 9, and Chrome. I usually use Chrome. If the images look too
        > > > large to avoid scrolling, choose the "large" image rather than the
        > > > "original" which I linked to.
        > > >
        > > > My living room is pictured in two photos in my photo album:
        > > >
        > > >
        > > http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/1807486073/view?picmode=original&mode=tn&order=ordinal&start=121&dir=asc
        > > >
        > > >
        > > http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/1220989556/view?picmode=large&mode=tn&order=ordinal&start=141&dir=asc
        > > >
        > > > I have not measured the living room. I'd guess that it at least 15' x
        > > 25'.
        > > > As you can see in the first picture, there is a large cased opening to
        > > the
        > > > right rear connecting to a dining room, so my living room is kind of
        > > > L-shaped. There is a smaller cased opening into the kitchen, as well as a
        > > > long foyer connected to the living room by a large cased opening to the
        > > > left. I'd say the middle of the measured left channel Stirling is about
        > > > 30" from the wall behind it and about six feet from the wall to the left
        > > of
        > > > it. The stands are 14.75" tall. The stands the AR-303a's behind the
        > > > Stirlings are on are 24" tall and the center of those speakers is about
        > > 18"
        > > > from the wall behind them. The equipment cabinet is 18" deep.
        > > >
        > > > Tom
        > > >
        > > >
        > > >
        > > > On Mon, Apr 22, 2013 at 11:52 AM, Tip Johnson <Tip_Johnson@> wrote:
        > > >
        > > > > **
        > > > >
        > > > >
        > > > > Hi Laurie,
        > > > >
        > > > > > Very ineresting to see thes. I actually found it easier to
        > > > > > download these as .jpg's onto hard disc due to the way Yahoo
        > > > > > presents those graphs, with large blank areas above and below
        > > > > > the graphs and with the panning strip right at the bottom.
        > > > > > The .jpg then fits comfortably into a screen window, unlike
        > > > > > the way yahoo displays it.
        > > > >
        > > > > At the upper left-hand side of the Yahoo window there is a "View"
        > > control
        > > > > for the photos. You can select "Medium", "Large", or
        > > > > "Original". The view probably was set to "Original" if there was a
        > > panning
        > > > > strip at the bottom (the graphs TM posted were too big
        > > > > to fit into the window in their original size.) Next time click on
        > > "Large"
        > > > > or "Medium" to reduce the size of the graph to fit into
        > > > > the screen window.
        > > > >
        > > > > Best Regards,
        > > > > Tip
        > > > >
        > > > >
        > > > >
        > > >
        > >
        > >
        > >
        >


      • Robert
        There is some truth here. BUT--and it is a significant but , TM seems to have some trouble with the truth here. Look carefully at the M30 measurements(forget
        Message 3 of 22 , Apr 22 8:20 PM
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          There is some truth here. BUT--and it is a significant
          but , TM seems to have some trouble with the truth here.
          Look carefully at the M30 measurements(forget SPhiles
          measurements which are, as everyone knows, all wrong in the bass).
          What is really going on is that the bass at its highest
          point is about 3dB above the midrange level(look at the curve on the THD chart---you can see the on axis all by itself), There is
          an overall slight recession between 2 and 5k relative to the 1k level. Then the speaker returns to the mid level(the 1kHz level) at
          10k.
          This is not all that peculiar! If you whacked off 3 dB of bass
          (around 100 Hz) you would get a speaker that was quite flat,
          except for the receession of the 2-5 kHz region.
          As people have no doubt read on Linkwitz's site there
          is logic in pushing down 3kHz.
          You might want to compare all this to this
          http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=754:nrc-measurements-psb-imagine-t2-loudspeakers&catid=77:loudspeaker-measurements
          Note that this too is slightly up at 100 and a little down at 2k--
          not so much as the Harbeth, but the general deviation is similar.
          (put the edge of a piece of paper on the graph to see what
          really goes on). Five hundred Hz stick up a little here instead
          of slightly further up.

          The BIG difference come in the off axis. The M30 is really out of there in the far off axis at around 2k. Way down. The speakers have
          quite different "room responses". You need to sit close to the M30s
          to hear "neutral balance" is one way to think of it. Another way
          to think of it is that the M30s do to the room sound around 3k what
          ought to be done(cf Linkwitz) as to diffuse field EQ.
          (the flare above 2-3 k is not important--you can soak it up easily).

          All the BBC heritage speakers that run a large midrange driver up
          fairly far do this bit about the far off axis. And why not?
          This is what the BBC determined to sound right in comparison to
          live music.

          Once again, don't pay any mind to what TM says about things
          like 12 dB extra bass. The speaker is up 3 dB in the bass over
          its mid level. That is all it is. Room plus speaker is a linear
          system. You will get 3 dB more bass than if the speaker
          were flat in the bass(and the driver was in the same place).
          This is not a matter of controversy or discussion or experience
          or anything else. It is a fact. This is how dB work for linear
          systems. This 12 dB stuff is improvisation intellectually and bad placement(and strange room) physically. The M30 has 3 dB extra at 100 k. End of story.
          Only audiophiles think that speakers exhibit bass differently in rooms according to the brand of speaker. An omni radiator(which they are at 100 Hz) that has 3 dB more anechoic bass has 3 dB more bass in room(driver placement being the same). Arithmetic is what we are discussing here.

          Small changes in frequency response make differences. But the M30
          is not that far from flat. Except in its far off axis responses above 1k. And those are different from the narrow front wide radiation speakers.
          If you want those uniform*except for the top octave which no sensible person wants uniform), buy an Ethera Vitae(and turn the treble down a little).



          REG





          --- In regsaudioforum@yahoogroups.com, Tom Mallin <tmallin4@...> wrote:
          >
          > As modern speakers go, Harbeths are odd ducks in terms of frequency
          > balance. Very nicely odd ducks, but odd nonetheless. Look at the
          > Soundstage anechoic measurements of the Harbeth M30. I'm sure that
          > everyone who has heard both that speaker and the M40/40.1 will agree that
          > in most any room the larger speaker is even warmer balanced with more
          > midbass. Compare the amount of response at 100 Hz in those anechoic
          > measurements to the response at 1 kHz. The 100 Hz response is 4 dB up and
          > the entire response slopes down from bass to treble. Now look for any
          > other speaker in the Soundstage measurements that has that kind of
          > response. The only other one that is remotely similar is the Cerwin Vega
          > CLS 215, another REG rave.
          >
          > Look at the other measurements I took on the same day with the speakers on
          > the same stand in the same spot in my basement. Do any other speakers show
          > 100 Hz up 12 dB? No, far from it. The woofers of all the speakers were
          > within a couple of inches of the same distance from the floor and walls.
          > The Harbeth M40.1 obviously has a lot more midbass than any of the other
          > speakers. The room should affect all those speakers about the same way.
          >
          > The generous overall low-end response of Harbeths allows you to cut off the
          > bass peaks with electronic EQ very easily and still not suffer from thin
          > sound because the low frequency dips are still near the reference level of
          > 1 kHz. That's why they are nicely odd ducks. You can easily EQ them
          > flatter in the the bass without having to boost the overall bass level to
          > avoid low frequency thinness. The Harbeths will then will play more loudly
          > with less distortion since both amps and speakers are loafing along.
          >
          >
          >
          > On Mon, Apr 22, 2013 at 3:45 PM, Robert <regtas43@...> wrote:
          >
          > > **
          > >
          > >
          > > You can just tape the mike on with Duc tape.
          > > Messy but it works. The RTA is fine for in room
          > > stuff and if you look at how it changes
          > > with distance you can get a pretty good idea
          > > of how the speaker would look anechoically.
          > > A little practice does wonders.
          > >
          > > I don't think TM has the speakers in quite
          > > optimum positions. The M40 ought to be a lot
          > > smoother in the bottom and more neutrally
          > > balanced if it were in the right place.
          > > And the LS3/6 does not have a dip at 200 Hz
          > > if you set it up correctly.
          > >
          > > Below around 500 Hz, position is important!
          > > (and the nature of the room). Look at the differences
          > > between JAs in room responses (good) and those of
          > > some of the other writers(not so good) when he
          > > shows both.
          > >
          > > Below 500 Hz, the speaker does not rule --the
          > > room rules. The speakers tend to be very similar
          > > except for absolute extension. Look at the NRC measurements.
          > > Bass is pretty much predictable and usually quite smooth.
          > > The Harbeths are a bit warmed up but it is not wild and crazy.
          > > The wild and crazy effects come from not knowing where
          > > to put them and/or having a weird room/
          > > Neither the Harbeth nor any other speaker I can think of
          > > has a 12 dB rise anywhere.
          > >
          > > Audiophiles find it really hard to give up the idea
          > > that it is the equipment that is doing what they
          > > hear and/or measure. Below 500 Hz, not so.
          > > Measurements in that region are mostly measurements
          > > of how much you (or your room) messed up. But most
          > > rooms(TMs is an exception) are not such a big problem.
          > > If you know where to put the speaker....experimentation
          > > is the key.
          > >
          > > Don't believe this stuff TM put up in the lower
          > > frequencies. Not really what the speaker does,
          > > just what it does in the wrong place, mostly.
          > >
          > > REG
          > >
          > > --- In regsaudioforum@yahoogroups.com, Tom Mallin <tmallin4@> wrote:
          > > >
          > > > Kevin, my photo album contains many other measurements taken of the
          > > Harbeth
          > > > M40 and M40.1 speakers. All the prior measurements were taken in my audio
          > > > room, which is very symmetrical as rooms go (left and right channels
          > > always
          > > > measure virtually the same before EQ) about 20' x13' x 8' and has all
          > > > concrete walls and floor. There is drywall and insulation over the wall
          > > > concrete and carpet and padding on the floor, but no bass trapping. It is
          > > > my very own concrete basement bunker boom-boom box; it is a very atypical
          > > > audio room; the walls are very stiff and thus I thus get huge sharp peaks
          > > > and dips in the bass compared to other rooms.
          > > >
          > > > Most of these prior measurements were taken with either this same Liberty
          > > > Instruments SynRTA software and Girardin microphone (you can tell from
          > > the
          > > > pictures) or my TacT 2.2XP using a calibrated LinearX M31 microphone.
          > > > There are also a few taken using Liberty Instrument's Praxis.
          > > >
          > > > Basically, in my audio room, before EQ, the M40.1 has about an 8 dB
          > > high-Q
          > > > peak centered around 60 - 70 Hz. The M40 peak, seemed twice this large,
          > > > but REG disputes how I read the graphs. Whatever; there is is a big peak
          > > > around that frequency in that room with either speaker. Also, there is
          > > not
          > > > much bass from either of those speakers below 50 Hz or so; thus I use
          > > > subwoofers with those Harbeths. I then use electronic EQ of some sort
          > > > (I've used Cello Palette Preamp, Z-Systems rdp-1, Rives PARC, Rane
          > > DEQ-60L,
          > > > Audient ASP231, Behringer DEQ2496, TacT RCS 2.2XP, and now soon the
          > > > DSPeaker DualCore, among others) to flatten the bass. The M40s were
          > > > unlistenable in this room without electronic EQ; the M40.1s are whumpy
          > > but
          > > > listenable without EQ, at least short term. All other speakers I've used
          > > > in this room benefited from bass electronic EQ as well, but none have
          > > > needed it as desperately as the Harbeths.
          > > >
          > > > In my newest graphs taken in the home theater area, the M40.1 peak is now
          > > > 12 dB, but is up higher in frequency and seemingly lower in Q (more
          > > spread
          > > > out). And there is now bass at the 1 kHz reference level down to 25 Hz.
          > > > That's what I meant when I said this new room "transformed" the M40.1
          > > > bass. There is still a big peak, but it's now above the midbass thump
          > > > frequency, is more spread out and seems part of a general rise in low-end
          > > > response, could energize the power range of an orchestra, plus there is
          > > > considerable bottom-octave bass.
          > > >
          > > > I own and could always use Liberty Instruments Praxis measuring suite,
          > > > which is a rather sophisticated system. But I've found the free SynRTA
          > > > software, also by Liberty, to provide very similar results and to be much
          > > > easier to use for adjusting things since, unlike Praxis, it displays
          > > > results in real time as you move things, taking only a few seconds to
          > > > refresh. I do use the Liberty Audio AudPod (which is necessary for
          > > Praxis)
          > > > with SynRTA since part of its function is to act as a microphone preamp.
          > > > You CAN use the Girardin mike straight into a sound card (I use an
          > > M-Audio
          > > > Transit, as once and still recommended by and available from Liberty
          > > > Instruments for Praxis), but the levels of test tone noise necessary to
          > > > make the measurements are then about 20 dB higher and are nasty on the
          > > ears
          > > > that way after a few minutes. With the Audpod/mike preamp, the levels
          > > > needed are moderate and easy to take for quite awhile.
          > > >
          > > > Most good microphones need some sort of microphone preamp between the
          > > mike
          > > > and the sound card since microphone output is usually very low. And the
          > > > sound cards typically installed in PCs are not very flat over the audio
          > > > range. Now, some measuring programs promise to correct for the inadequacy
          > > > of built-in sound cards, buy I have not followed that route. Also, there
          > > > may well be some fine USB mikes with built in sound cards and preamps out
          > > > there these days, but I have not investigated them, being content to plod
          > > > along with the now-rather-antiquated system I use since it seems to
          > > produce
          > > > accurate results. Roger Sanders told me that my measurements of his
          > > > Sanders 10C speakers were within the best expectable experimental
          > > variation
          > > > compared to the measurements he got using CalTech's anechoic chamber and
          > > a
          > > > very sophisticated measurement rig.
          > > >
          > > > The Girardin mike I use (also available from Liberty Instruments) has an
          > > > RCA jack output, so I use 5 meters of unbalanced Joseph Grado Signature
          > > > cable (not that the cable matters, but it just happens to not be in use
          > > in
          > > > any of my audio systems and is long enough and quite flexible) on the
          > > > output to plug it into the AudPod/preamp via some cheapo RCA jack/mini
          > > > phone plug adapters. The AudPod connects to the M-Audio sound card via
          > > > cheap short miniplug cables, and then a very short USB cable connects the
          > > > sound card to a USB input of an old Dell Latitude D600 laptop running XP.
          > > > I use this laptop for sound measurements since it's old enough to have a
          > > > 9-pin serial port and can thus easily connect to my TacT RCS 2.2 XP.
          > > >
          > > > I also always use a boom-type mike stand with a tripod base for maximum
          > > > stability and minimum conduction of bass frequencies through the floor
          > > into
          > > > the mike. I have used a number of brands of stand, but find that On-Stage
          > > > Stands are sturdy, cheap, and easiest to adjust. You want the stand short
          > > > enough so that the boom arm can angle down and away from the mike when
          > > the
          > > > mike is at measuring height. That puts the mike in as much free space as
          > > > possible. For a high sitting position, like 48", a 30" high stand is
          > > fine.
          > > > For lower positions, like 38", I use what is sold as a bass drum stand,
          > > > which is considerably shorter even at maximum extension.
          > > >
          > > > Part of the problem with measuring mikes is getting a microphone stand
          > > > adaptor small enough in diameter to work with the things; most standard
          > > > mike clips are made for much larger in diameter mikes. The clip that
          > > comes
          > > > with the LinearX fits the mike barrel but is not durable and is a poor
          > > fit
          > > > for standard mike stands; I'm on my third or fourth one--the plastic that
          > > > holds the mike keeps splitting. The Girardin is ideal in this respect
          > > > since the mike comes with a sturdy totally integrated clip that is the
          > > > perfect fit for mike boom threads and has just the right amount of
          > > tension
          > > > in the adjustment to stay put at any given angle yet allow it to be
          > > > adjusted without applying too much torque.
          > > >
          > > > I'd stay away from the Behringer ECM8000 mike. At $50 it's cheap, but it
          > > > is not calibrated and users have found a plus or minus 5 dB or more
          > > > variation in the mike's low and high frequency measured response. The
          > > > LinearX and Girardin both come with calibration files which individually
          > > > calibrate each serial number of the mikes and even before calibration
          > > seem
          > > > to be better than plus or minus a dB or two from flat over the entire
          > > audio
          > > > range.
          > > >
          > > >
          > > >
          > > >
          > > > On Mon, Apr 22, 2013 at 12:48 PM, kevindoyle.forum <doyle.kevin@
          > > ...>wrote:
          > > >
          > > > > **
          > > > >
          > > > >
          > > > > Looks fine on Chrome on OSX. Thank you for sharing your measurements,
          > > TM.
          > > > >
          > > > > REG alluded to some problems you had with the M40.1's in terms of bass.
          > > > > What were they? And were they without your various means of EQ? Sorry
          > > to
          > > > > rehash, but I don't rceall the specifics and I'm curious, having
          > > recently
          > > > > seen a long thread on HUG about the bass. It seemed to me something
          > > that
          > > > > could have been easily addressed.
          > > > >
          > > > > One other question, the mic you use is USB plugged straight into
          > > laptop?
          > > > > I'm looking into measurement tools now and want a combination of
          > > effective
          > > > > and inexpensive.
          > > > >
          > > > > Anyway, thanks again! If this is what you do with a day off, I can't
          > > wait
          > > > > until you retire. Great stuff.
          > > > >
          > > > > --- In regsaudioforum@yahoogroups.com, Tom Mallin <tmallin4@> wrote:
          > > > > >
          > > > > > I do not have the problem viewing the graphs via Yahoo you have,
          > > Laurie,
          > > > > on
          > > > > > any of the three desktops and one laptop I've used. The viewing
          > > problems
          > > > > > are probably caused by a combination of your screen size, screen
          > > > > > resolution, and internet browser. I know that IE10 is causing
          > > vertically
          > > > > > squished images on a number of our office computers; those same
          > > images
          > > > > look
          > > > > > fine in IE8, 9, and Chrome. I usually use Chrome. If the images look
          > > too
          > > > > > large to avoid scrolling, choose the "large" image rather than the
          > > > > > "original" which I linked to.
          > > > > >
          > > > > > My living room is pictured in two photos in my photo album:
          > > > > >
          > > > > >
          > > > >
          > > http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/1807486073/view?picmode=original&mode=tn&order=ordinal&start=121&dir=asc
          > > > > >
          > > > > >
          > > > >
          > > http://groups.yahoo.com/group/regsaudioforum/photos/album/404627898/pic/1220989556/view?picmode=large&mode=tn&order=ordinal&start=141&dir=asc
          > > > > >
          > > > > > I have not measured the living room. I'd guess that it at least 15' x
          > > > > 25'.
          > > > > > As you can see in the first picture, there is a large cased opening
          > > to
          > > > > the
          > > > > > right rear connecting to a dining room, so my living room is kind of
          > > > > > L-shaped. There is a smaller cased opening into the kitchen, as well
          > > as a
          > > > > > long foyer connected to the living room by a large cased opening to
          > > the
          > > > > > left. I'd say the middle of the measured left channel Stirling is
          > > about
          > > > > > 30" from the wall behind it and about six feet from the wall to the
          > > left
          > > > > of
          > > > > > it. The stands are 14.75" tall. The stands the AR-303a's behind the
          > > > > > Stirlings are on are 24" tall and the center of those speakers is
          > > about
          > > > > 18"
          > > > > > from the wall behind them. The equipment cabinet is 18" deep.
          > > > > >
          > > > > > Tom
          > > > > >
          > > > > >
          > > > > >
          > > > > > On Mon, Apr 22, 2013 at 11:52 AM, Tip Johnson <Tip_Johnson@> wrote:
          > > > > >
          > > > > > > **
          > > > > > >
          > > > > > >
          > > > > > > Hi Laurie,
          > > > > > >
          > > > > > > > Very ineresting to see thes. I actually found it easier to
          > > > > > > > download these as .jpg's onto hard disc due to the way Yahoo
          > > > > > > > presents those graphs, with large blank areas above and below
          > > > > > > > the graphs and with the panning strip right at the bottom.
          > > > > > > > The .jpg then fits comfortably into a screen window, unlike
          > > > > > > > the way yahoo displays it.
          > > > > > >
          > > > > > > At the upper left-hand side of the Yahoo window there is a "View"
          > > > > control
          > > > > > > for the photos. You can select "Medium", "Large", or
          > > > > > > "Original". The view probably was set to "Original" if there was a
          > > > > panning
          > > > > > > strip at the bottom (the graphs TM posted were too big
          > > > > > > to fit into the window in their original size.) Next time click on
          > > > > "Large"
          > > > > > > or "Medium" to reduce the size of the graph to fit into
          > > > > > > the screen window.
          > > > > > >
          > > > > > > Best Regards,
          > > > > > > Tip
          > > > > > >
          > > > > > >
          > > > > > >
          > > > > >
          > > > >
          > > > >
          > > > >
          > > >
          > >
          > >
          > >
          >
        • kevindoyle.forum
          Thank you, TM, REG, and Ted for the helpful replies to my query. I will likely be asking a lot more questions as I get closer to a purchase. Your help is
          Message 4 of 22 , Apr 23 9:36 AM
          • 0 Attachment
            Thank you, TM, REG, and Ted for the helpful replies to my query. I will likely be asking a lot more questions as I get closer to a purchase. Your help is very much appreciated.

            BTW, in reference to the M40.1 and its measurements, I think post #181 and #185 are worth a look.

            http://www.harbeth.co.uk/usergroup/showthread.php?312-Harbeth-Monitor-40-1-specific/page10

            Really, the whole page is worthwhile. Anyway, this is what I had in mind when bass issues were mentioned. As Alan had said in post #154:

            "Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....

            1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or

            2. Change or somehow modify the speakers themselves to pump less bass into the room and/or

            3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal."

            Anyway, thanks again, gentlemen. This forum truly is a pleasure.


            --- In regsaudioforum@yahoogroups.com, "Ted Rook" <rooknrol@...> wrote:
            >
            > On 22 Apr 2013 at 17:48, kevindoyle.forum wrote:
            >
            > I'm looking into measurement tools now and want a
            > > combination of effective and inexpensive.
            >
            >
            > >Some measuring choices for you to consider, these are my measurement tools, which I
            > have been using happily for the past six years to help set up my M40s in-room.
            >
            >
            > measurement microphone: calibrated NTI "miniSPL" 0.5 inch mic includes battery power (no
            > phantom power supply required) and includes internal preamp, no external preamp is
            > required, it plugs straight into your sound card input. You will need to source a regular XLR
            > mic cable and a converter to go from XLR to soundcard 0.125 inch minijack. Comes in a nice
            > hardcase with calibration certificate. Buy online from NTI America $375
            >
            > http://shop.nti-audio.com/pd_minispl.cfm
            >
            >
            > Real time audio analyzer for windows: TrueRTA software, configured for stereo
            > measurement using the windows soundcard inputs and outputs, includes precision signal
            > generator, precision real time analyzer, 1/3rd octave version costs $40, the 1/24th octave
            > version is $100. This is fully debugged and supported software, I have never had a moment
            > of trouble on two different windows machines. It operates in real time all the time, until TM
            > mentioned that SynRTA is nearly real time it never occurred to me that there could be
            > anything other than real time real-time analyzers, this is a full-time real-time
            > real-time-analyzer, instantaneous response time, using traditional sinewave, swept tone, pink
            > noise and white noise sources, pink noise being the most useful for room measurements
            > since the wished for flat response is a horizontal straight line.
            >
            > http://trueaudio.com/rta_abt1.htm
            >
            >
            > Both are a pleasure to use.
            >
            > Any questions feel free to ask.
            >
            > Ted
            >
          • Peter
            ...   In order from most bass to least bass:   1.    Bipoles 2.    Monopoles 3.    Hybrids (i.e., electrostatic + cone woofer) 4.    Dipoles
            Message 5 of 22 , Apr 23 9:42 AM
            • 0 Attachment
              > 2. Change or somehow modify the speakers themselves to pump less bass into the room and/or
               
              In order from most bass to least bass:
               
              1.    Bipoles
              2.    Monopoles
              3.    Hybrids (i.e., electrostatic + cone woofer)
              4.    Dipoles
              class="tab"> 
              I don't know what if any bass difference there is between planar dipoles and Linkwitz-style open baffle dynamic drivers.

              From: kevindoyle.forum <doyle.kevin@...>
              To: regsaudioforum@yahoogroups.com
              Sent: Tuesday, April 23, 2013 12:36 PM
              Subject: [regsaudioforum] Re: Speaker Measurements
               
              Thank you, TM, REG, and Ted for the helpful replies to my query. I will likely be asking a lot more questions as I get closer to a purchase. Your help is very much appreciated.

              BTW, in reference to the M40.1 and its measurements, I think post #181 and #185 are worth a look.

              http://www.harbeth.co.uk/usergroup/showthread.php?312-Harbeth-Monitor-40-1-specific/page10

              Really, the whole page is worthwhile. Anyway, this is what I had in mind when bass issues were mentioned. As Alan had said in post #154:

              "Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....

              1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or

              2. Change or somehow modify the speakers themselves to pump less bass into the room and/or

              3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal."

              Anyway, thanks again, gentlemen. This forum truly is a pleasure.

              --- In mailto:regsaudioforum%40yahoogroups.com, "Ted Rook" <rooknrol@...> wrote:
              >
              > On 22 Apr 2013 at 17:48, kevindoyle.forum wrote:
              >
              > I'm looking into measurement tools now and want a
              > > combination of effective and inexpensive.
              >
              >
              > >Some measuring choices for you to consider, these are my measurement tools, which I
              > have been using happily for the past six years to help set up my M40s in-room.
              >
              >
              > measurement microphone: calibrated NTI "miniSPL" 0.5 inch mic includes battery power (no
              > phantom power supply required) and includes internal preamp, no external preamp is
              > required, it plugs straight into your sound card input. You will need to source a regular XLR
              > mic cable and a converter to go from XLR to soundcard 0.125 inch minijack. Comes in a nice
              > hardcase with calibration certificate. Buy online from NTI America $375
              >
              > http://shop.nti-audio.com/pd_minispl.cfm
              >
              >
              > Real time audio analyzer for windows: TrueRTA software, configured for stereo
              > measurement using the windows soundcard inputs and outputs, includes precision signal
              > generator, precision real time analyzer, 1/3rd octave version costs $40, the 1/24th octave
              > version is $100. This is fully debugged and supported software, I have never had a moment
              > of trouble on two different windows machines. It operates in real time all the time, until TM
              > mentioned that SynRTA is nearly real time it never occurred to me that there could be
              > anything other than real time real-time analyzers, this is a full-time real-time
              > real-time-analyzer, instantaneous response time, using traditional sinewave, swept tone, pink
              > noise and white noise sources, pink noise being the most useful for room measurements
              > since the wished for flat response is a horizontal straight line.
              >
              > http://trueaudio.com/rta_abt1.htm
              >
              >
              > Both are a pleasure to use.
              >
              > Any questions feel free to ask.
              >
              > Ted
              >

            • Tom Mallin
              For a given surface area of woofer, cone dipoles will play louder in the low bass for any given baffle width. Cones can excurse a quarter inch or more back
              Message 6 of 22 , Apr 23 10:06 AM
              • 0 Attachment
                For a given surface area of woofer, cone dipoles will play louder in the low bass for any given baffle width.  Cones can excurse a quarter inch or more back and forth with low distortion.  A flat panel diaphragm is very limited in terms of low-distortion excursion capability.  Thus, the cone woofers potentially can move more air, and that's the name of the game for dipoles at low frequencies.  For any given dipole speaker and SPL, the diaphragms must move four times further back and forth for every octave drop in frequency.

                Of course, big bass panels like those in the larger Maggies have the square inches of several 12" woofers.  But in my experience cone dipole woofers can more than make up the difference since they have far greater low-distortion excursion capability.  And my adding six additional 12-inchers per side of  the Gradient Revolution Active adds a lot of surface area.  The additional woofers raises the SPL capability by 12 dB over the basic Revolution (which has two 12s per side) at any given bass frequency for equivalent distortion and cone excursion.


                On Tue, Apr 23, 2013 at 11:42 AM, Peter <alcomdata@...> wrote:
                 

                > 2. Change or somehow modify the speakers themselves to pump less bass into the room and/or
                 
                In order from most bass to least bass:
                 
                1.    Bipoles
                2.    Monopoles
                3.    Hybrids (i.e., electrostatic + cone woofer)
                4.    Dipoles
                 
                I don't know what if any bass difference there is between planar dipoles and Linkwitz-style open baffle dynamic drivers.

                From: kevindoyle.forum <doyle.kevin@...>
                To: regsaudioforum@yahoogroups.com
                Sent: Tuesday, April 23, 2013 12:36 PM
                Subject: [regsaudioforum] Re: Speaker Measurements
                 
                Thank you, TM, REG, and Ted for the helpful replies to my query. I will likely be asking a lot more questions as I get closer to a purchase. Your help is very much appreciated.

                BTW, in reference to the M40.1 and its measurements, I think post #181 and #185 are worth a look.

                http://www.harbeth.co.uk/usergroup/showthread.php?312-Harbeth-Monitor-40-1-specific/page10

                Really, the whole page is worthwhile. Anyway, this is what I had in mind when bass issues were mentioned. As Alan had said in post #154:

                "Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....

                1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or

                2. Change or somehow modify the speakers themselves to pump less bass into the room and/or

                3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal."

                Anyway, thanks again, gentlemen. This forum truly is a pleasure.

                --- In mailto:regsaudioforum%40yahoogroups.com, "Ted Rook" <rooknrol@...> wrote:
                >
                > On 22 Apr 2013 at 17:48, kevindoyle.forum wrote:
                >
                > I'm looking into measurement tools now and want a
                > > combination of effective and inexpensive.
                >
                >
                > >Some measuring choices for you to consider, these are my measurement tools, which I
                > have been using happily for the past six years to help set up my M40s in-room.
                >
                >
                > measurement microphone: calibrated NTI "miniSPL" 0.5 inch mic includes battery power (no
                > phantom power supply required) and includes internal preamp, no external preamp is
                > required, it plugs straight into your sound card input. You will need to source a regular XLR
                > mic cable and a converter to go from XLR to soundcard 0.125 inch minijack. Comes in a nice
                > hardcase with calibration certificate. Buy online from NTI America $375
                >
                > http://shop.nti-audio.com/pd_minispl.cfm
                >
                >
                > Real time audio analyzer for windows: TrueRTA software, configured for stereo
                > measurement using the windows soundcard inputs and outputs, includes precision signal
                > generator, precision real time analyzer, 1/3rd octave version costs $40, the 1/24th octave
                > version is $100. This is fully debugged and supported software, I have never had a moment
                > of trouble on two different windows machines. It operates in real time all the time, until TM
                > mentioned that SynRTA is nearly real time it never occurred to me that there could be
                > anything other than real time real-time analyzers, this is a full-time real-time
                > real-time-analyzer, instantaneous response time, using traditional sinewave, swept tone, pink
                > noise and white noise sources, pink noise being the most useful for room measurements
                > since the wished for flat response is a horizontal straight line.
                >
                > http://trueaudio.com/rta_abt1.htm
                >
                >
                > Both are a pleasure to use.
                >
                > Any questions feel free to ask.
                >
                > Ted
                >


              • Robert
                This is surely an odd description. Any type of speaker can have a lot of bass. I suppose that what this means is in practice? But even for in practice it seems
                Message 7 of 22 , Apr 23 5:57 PM
                • 0 Attachment
                  This is surely an odd description. Any type of
                  speaker can have a lot of bass. I suppose that what
                  this means is in practice? But even for in practice it
                  seems rather confused. It is surely not
                  true that bipolar speakers have more bass than monopoles
                  for example in the bass since monopole speakers
                  operate as omnis as do "bipoles". Whether you have
                  two woofers one on front and one on back or
                  two on front makes no real difference at all.
                  And of course hybrid speakers have dynamic driver
                  bass-that is what the hybrid part is about. They
                  can have as much bass as one likes.

                  Do people just make this stuff up for fun?

                  The real issue is dipole rolloff. Because
                  of dipole cancellation, a dipole radiator
                  needs a LOT of area and excursion to produce
                  deep bass at volume--and indeed it cannot really
                  go all the way down. The original Carver Amazings
                  and the Gradients with enough panels do go
                  down far. But because they roll off below they
                  are not so phase linear as a box subwoofer that
                  goes down to say 5 Hz(which is doable). Since
                  bass in rooms in so room affected, this is probably
                  not so very important. If you have as much response
                  as you wish, then you will be happy.

                  Incidentally, what REALLY works(a la Peter's improvisation)
                  is corner woofers, where the loading of the woofers
                  is really good and deep bass is relatively easily
                  produced. If you really want the deepest most solid bass, corner woofers
                  are the way to go in my experience.

                  On the other hand, the dipole bass relates to the room
                  a bit differently and lots of people like the results.

                  REG
                  --- In regsaudioforum@yahoogroups.com, Peter <alcomdata@...> wrote:
                  >
                  > > 2. Change or somehow modify the speakers themselves to pump less bass into the room and/or
                  >  
                  > In order from most bass to least bass:
                  >  
                  > 1.    Bipoles
                  > 2.    Monopoles
                  > 3.    Hybrids (i.e., electrostatic + cone woofer)
                  > 4.    Dipoles
                  >  
                  > I don't know what if any bass difference there is between planar dipoles and Linkwitz-style open baffle dynamic drivers.
                  >
                  >
                  > ________________________________
                  > From: kevindoyle.forum <doyle.kevin@...>
                  > To: regsaudioforum@yahoogroups.com
                  > Sent: Tuesday, April 23, 2013 12:36 PM
                  > Subject: [regsaudioforum] Re: Speaker Measurements
                  >
                  >  
                  >
                  > Thank you, TM, REG, and Ted for the helpful replies to my query. I will likely be asking a lot more questions as I get closer to a purchase. Your help is very much appreciated.
                  >
                  > BTW, in reference to the M40.1 and its measurements, I think post #181 and #185 are worth a look.
                  >
                  > http://www.harbeth.co.uk/usergroup/showthread.php?312-Harbeth-Monitor-40-1-specific/page10
                  >
                  > Really, the whole page is worthwhile. Anyway, this is what I had in mind when bass issues were mentioned. As Alan had said in post #154:
                  >
                  > "Almost all domestic rooms have far, far less absorption than ideal for listening to hi-fi minus the room's overarching contribution. And that really is the nub of the problem. There are three ways forward ....
                  >
                  > 1. Increase the damping and hence absorption in the room, perhaps significantly and accept that the acoustic treatment is going to impact on the cosmetics - which just may not be acceptable and/or
                  >
                  > 2. Change or somehow modify the speakers themselves to pump less bass into the room and/or
                  >
                  > 3. Introduce some electronic adjustment in the signal path (of the amp) to reduce the amount of drive to the speakers in regions where the room's absorption is lower than ideal."
                  >
                  > Anyway, thanks again, gentlemen. This forum truly is a pleasure.
                  >
                  > --- In mailto:regsaudioforum%40yahoogroups.com, "Ted Rook" <rooknrol@> wrote:
                  > >
                  > > On 22 Apr 2013 at 17:48, kevindoyle.forum wrote:
                  > >
                  > > I'm looking into measurement tools now and want a
                  > > > combination of effective and inexpensive.
                  > >
                  > >
                  > > >Some measuring choices for you to consider, these are my measurement tools, which I
                  > > have been using happily for the past six years to help set up my M40s in-room.
                  > >
                  > >
                  > > measurement microphone: calibrated NTI "miniSPL" 0.5 inch mic includes battery power (no
                  > > phantom power supply required) and includes internal preamp, no external preamp is
                  > > required, it plugs straight into your sound card input. You will need to source a regular XLR
                  > > mic cable and a converter to go from XLR to soundcard 0.125 inch minijack. Comes in a nice
                  > > hardcase with calibration certificate. Buy online from NTI America $375
                  > >
                  > > http://shop.nti-audio.com/pd_minispl.cfm
                  > >
                  > >
                  > > Real time audio analyzer for windows: TrueRTA software, configured for stereo
                  > > measurement using the windows soundcard inputs and outputs, includes precision signal
                  > > generator, precision real time analyzer, 1/3rd octave version costs $40, the 1/24th octave
                  > > version is $100. This is fully debugged and supported software, I have never had a moment
                  > > of trouble on two different windows machines. It operates in real time all the time, until TM
                  > > mentioned that SynRTA is nearly real time it never occurred to me that there could be
                  > > anything other than real time real-time analyzers, this is a full-time real-time
                  > > real-time-analyzer, instantaneous response time, using traditional sinewave, swept tone, pink
                  > > noise and white noise sources, pink noise being the most useful for room measurements
                  > > since the wished for flat response is a horizontal straight line.
                  > >
                  > > http://trueaudio.com/rta_abt1.htm
                  > >
                  > >
                  > > Both are a pleasure to use.
                  > >
                  > > Any questions feel free to ask.
                  > >
                  > > Ted
                  > >
                  >
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