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Re: [regsaudioforum] Re: Subwoofer distortion

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  • mitch bucanon
    Hi, Have a look there: http://www.avtalk.co.uk/showthread.php?t=12281 and there: http://www.hometheater.com/content/way-down-deep-i Just make sure you have
    Message 1 of 12 , Nov 29, 2012
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      Hi,

      Have a look there:
      http://www.avtalk.co.uk/showthread.php?t=12281
      and there:
      http://www.hometheater.com/content/way-down-deep-i
      Just make sure you have similar SPL to compare THD and vice-versa (have similar THD to compare SPL).

      Not the same standard but all subs can be compared  and you might reconsider this sentence:
      "If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art."

      FYI Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... Knowing that 
      1. higher THD might be such a big deal per se 
      2. at High SPL HD is less and less audible
        
      Other will have higher THD, right, but higher SPL as well so... going with "whatever the THD how does it sounds is the point" argument you migh want to balance your argument.
      I am no fanboy of Paradigm and 95dB at 20Hz @10% thd is OK for a consumer product but not ground breaking.

      From my experience a DIY sub (Sealed, 50L, with EQ) using this driver:
      http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1114&utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=AskAndAnswer&utm_content=Default
      Should have similar SPL at the very low end.

      Question though: if multi-sub is the way to go so what is the point of having a huge expensive sub when three smaller cheaper will trounce it in every respect?


      With regard to the price and claims of constructors, well blame that on the society that prevent people from acquiring skepticism and the HIFI mags that promote magical accessories.
      M   


      De : Robert <regtas43@...>
      À : regsaudioforum@yahoogroups.com
      Envoyé le : Vendredi 30 novembre 2012 1h34
      Objet : [regsaudioforum] Re: Subwoofer distortion

       
      This is truly fatuous in my opinion
      as a justification for calling 10% low distortion.
      The review was of a subwoofer that costs more than
      $4000. No one should be thinking that it nice that it
      is better than a lot of others--it darned
      well better be better than the ones
      that cost a lot less. And the product in question
      is not claiming to be pretty good as cheap
      subs go. It is claiming to be really good altogether.
      And Velodyne has less expensive subs
      that have much better distortion.

      What is all this? A Paradigm secret ad
      campaign here?

      The "state of the art" is not set by
      how bad things are on average but how
      good they can be.

      The Paradigm does what it does--play really
      loudly out of a rather small enclosure.
      But the evidence offered does not suggest it
      has really low distortion in terms of what
      is available.

      Whether this matters is up to your decision.
      But reviews should not mislead people.

      REG

      --- In regsaudioforum@yahoogroups.com, Peter <alcomdata@...> wrote:
      >
      > > Whether or not it matters
      > audibly, 10 % distoriton is NOT low compared
      > to what is available. It just is not.
      >
      > Of course it's not low in an absolute sense, and is rarely (if ever) tolerated in anything other than transducers under unusual conditions (except for tube amps, of course!)
      >  
      > But in relative terms?  If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art.
      >



    • Robert
      I have not listened to a Velodyne of recent vintage but the one I had around a while back surely did not seem to compress dynamically It uses feedback
      Message 2 of 12 , Nov 29, 2012
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        I have not listened to a Velodyne of recent
        vintage but the one I had around a while
        back surely did not seem to compress dynamically
        It uses feedback correction of driver motion
        but where is anything about dynamic compression?

        REG
        PS I went to the first link and got almost nothing..
        and I do not see anything about Paradigm on the second one.

        --- In regsaudioforum@yahoogroups.com, mitch bucanon <maiky76@...> wrote:
        >
        > Hi,
        >
        > Have a look there:
        > http://www.avtalk.co.uk/showthread.php?t=12281
        > and there:
        > http://www.hometheater.com/content/way-down-deep-i
        > Just make sure you have similar SPL to compare THD and vice-versa (have similar THD to compare SPL).
        >
        > Not the same standard but all subs can be compared  and you might reconsider this sentence:
        > "If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art."
        >
        > FYI Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... Knowing that 
        > 1. higher THD might be such a big deal per se 
        > 2. at High SPL HD is less and less audible
        >   
        > Other will have higher THD, right, but higher SPL as well so... going with "whatever the THD how does it sounds is the point" argument you migh want to balance your argument.
        > I am no fanboy of Paradigm and 95dB at 20Hz @10% thd is OK for a consumer product but not ground breaking.
        >
        > From my experience a DIY sub (Sealed, 50L, with EQ) using this driver:
        > http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1114&utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=AskAndAnswer&utm_content=Default
        > Should have similar SPL at the very low end.
        >
        > Question though: if multi-sub is the way to go so what is the point of having a huge expensive sub when three smaller cheaper will trounce it in every respect?
        >
        >
        > With regard to the price and claims of constructors, well blame that on the society that prevent people from acquiring skepticism and the HIFI mags that promote magical accessories.
        > M   
        >
        >
        > ________________________________
        > De : Robert <regtas43@...>
        > À : regsaudioforum@yahoogroups.com
        > Envoyé le : Vendredi 30 novembre 2012 1h34
        > Objet : [regsaudioforum] Re: Subwoofer distortion
        >
        >
        >  
        > This is truly fatuous in my opinion
        > as a justification for calling 10% low distortion.
        > The review was of a subwoofer that costs more than
        > $4000. No one should be thinking that it nice that it
        > is better than a lot of others--it darned
        > well better be better than the ones
        > that cost a lot less. And the product in question
        > is not claiming to be pretty good as cheap
        > subs go. It is claiming to be really good altogether.
        > And Velodyne has less expensive subs
        > that have much better distortion.
        >
        > What is all this? A Paradigm secret ad
        > campaign here?
        >
        > The "state of the art" is not set by
        > how bad things are on average but how
        > good they can be.
        >
        > The Paradigm does what it does--play really
        > loudly out of a rather small enclosure.
        > But the evidence offered does not suggest it
        > has really low distortion in terms of what
        > is available.
        >
        > Whether this matters is up to your decision.
        > But reviews should not mislead people.
        >
        > REG
        >
        > --- In regsaudioforum@yahoogroups.com, Peter <alcomdata@> wrote:
        > >
        > > > Whether or not it matters
        > > audibly, 10 % distoriton is NOT low compared
        > > to what is available. It just is not.
        > >
        > > Of course it's not low in an absolute sense, and is rarely (if ever) tolerated in anything other than transducers under unusual conditions (except for tube amps, of course!)
        > >  
        > > But in relative terms?  If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art.
        > >
        >
      • mitch bucanon
         Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the
        Message 3 of 12 , Nov 29, 2012
        • 0 Attachment
           Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... 

           
          I have not listened to a Velodyne of recent vintage but the one I had around a while back surely did not seem to compress dynamically
          It uses feedback correction of driver motion but where is anything about dynamic compression?


          Sorry the forum seems acting weirdly but correct they use feedback but they do use a dynamic compressor example for the DD15 whether they like to call it that or not :
           
          Compressor: because the dynamic range of the output is not the same than the input (25dB input dynamic at 100Hz and only 7.5dB at 20Hz in the above example) that is by definition a compressor.
          Dynamic: because the compression varies with input: it is nonexistent at low level (the first lower 2/3 lines) and only kicks in at higher level.
          The amplifier will only deliver a fixed power to the driver at 20Hz regardless on the variation at the input ABOVE a certain threshold. At 110dB SPL the compression at 20Hz is 17.5dB and only 7.5dB at 100dB.
           
          Note that all sub/drivers/amplifier have a natural compression behavior anyways.
           
          But never mind Velodyne or Paradigm or xxx and complains about price and actual performances; the question still stands:
          If multi-sub is the way to go so what is the point of having a huge expensive underperforming sub when three/four smaller cheaper ones will trounce it in every respect?
           
          There is an alternative way :
          http://www.behringer.com/EN/Products/NU3000DSP.aspx
          DSP functions include a sophisticated delay for delay-line loudspeakers, crossover, EQ (eight parametric, two dynamic)
          Here are independent measurements:
          http://www.diyaudio.com/forums/class-d/213071-behringer-inuke-nu3000-measurements.html
           
          Buy:
          4 of the drivers I have mentioned for 1000USD (BTW these drivers are closely related to the ones in this thing: http://www.hometheater.com/content/way-down-deep-i-genelec-hts6 ;-)
          2 NU3000DSP for 800USD
          4 boxes top 1000USD (pick yours there http://www.parts-express.com/cat/subwoofer-speaker-cabinets/289) .
          Grand total 3000USD with bits and pieces so still comfortably under 5000USD of the DD18 (or the 10000USD for the Genelec HTS6)  and about the same price than the DD15.  
           
          This will achieve significantly better performance (no compression with more than 110dB SPL at 20Hz) better frequency smoothness even without EQing (that is also included anyway) 
          They come with a guaranty as well!
          Yes you lose the motional feedback offers but you don’t need it anymore since the 4 subs will have far less thermal compression and much lower THD anyway.
           
          If one is really serious about low THD at LF then one should seriously consider saving money and get better performance by actually putting into use the state of the art thing...
          M


          De : Robert <regtas43@...>
          À : regsaudioforum@yahoogroups.com
          Envoyé le : Vendredi 30 novembre 2012 13h17
          Objet : [regsaudioforum] Re: Subwoofer distortion

           
          I have not listened to a Velodyne of recent
          vintage but the one I had around a while
          back surely did not seem to compress dynamically
          It uses feedback correction of driver motion
          but where is anything about dynamic compression?

          REG
          PS I went to the first link and got almost nothing..
          and I do not see anything about Paradigm on the second one.

          --- In regsaudioforum@yahoogroups.com, mitch bucanon <maiky76@...> wrote:
          >
          > Hi,
          >
          > Have a look there:
          > http://www.avtalk.co.uk/showthread.php?t=12281
          > and there:
          > http://www.hometheater.com/content/way-down-deep-i
          > Just make sure you have similar SPL to compare THD and vice-versa (have similar THD to compare SPL).
          >
          > Not the same standard but all subs can be compared  and you might reconsider this sentence:
          > "If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art."
          >
          > FYI Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... Knowing that 
          > 1. higher THD might be such a big deal per se 
          > 2. at High SPL HD is less and less audible
          >   
          > Other will have higher THD, right, but higher SPL as well so... going with "whatever the THD how does it sounds is the point" argument you migh want to balance your argument.
          > I am no fanboy of Paradigm and 95dB at 20Hz @10% thd is OK for a consumer product but not ground breaking.
          >
          > From my experience a DIY sub (Sealed, 50L, with EQ) using this driver:
          > http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1114&utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=AskAndAnswer&utm_content=Default
          > Should have similar SPL at the very low end.
          >
          > Question though: if multi-sub is the way to go so what is the point of having a huge expensive sub when three smaller cheaper will trounce it in every respect?
          >
          >
          > With regard to the price and claims of constructors, well blame that on the society that prevent people from acquiring skepticism and the HIFI mags that promote magical accessories.
          > M   
          >
          >
          > ________________________________
          > De : Robert <regtas43@...>
          > À : regsaudioforum@yahoogroups.com
          > Envoyé le : Vendredi 30 novembre 2012 1h34
          > Objet : [regsaudioforum] Re: Subwoofer distortion
          >
          >
          >  
          > This is truly fatuous in my opinion
          > as a justification for calling 10% low distortion.
          > The review was of a subwoofer that costs more than
          > $4000. No one should be thinking that it nice that it
          > is better than a lot of others--it darned
          > well better be better than the ones
          > that cost a lot less. And the product in question
          > is not claiming to be pretty good as cheap
          > subs go. It is claiming to be really good altogether.
          > And Velodyne has less expensive subs
          > that have much better distortion.
          >
          > What is all this? A Paradigm secret ad
          > campaign here?
          >
          > The "state of the art" is not set by
          > how bad things are on average but how
          > good they can be.
          >
          > The Paradigm does what it does--play really
          > loudly out of a rather small enclosure.
          > But the evidence offered does not suggest it
          > has really low distortion in terms of what
          > is available.
          >
          > Whether this matters is up to your decision.
          > But reviews should not mislead people.
          >
          > REG
          >
          > --- In regsaudioforum@yahoogroups.com, Peter <alcomdata@> wrote:
          > >
          > > > Whether or not it matters
          > > audibly, 10 % distoriton is NOT low compared
          > > to what is available. It just is not.
          > >
          > > Of course it's not low in an absolute sense, and is rarely (if ever) tolerated in anything other than transducers under unusual conditions (except for tube amps, of course!)
          > >  
          > > But in relative terms?  If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art.
          > >
          >



        • Peter
          Here s Audioholics complete review of the Velodyne DD-15+, with selected comparisons with the original DD-15.  
          Message 4 of 12 , Nov 30, 2012
          • 0 Attachment
            Here's Audioholics complete review of the Velodyne DD-15+, with selected comparisons with the original DD-15.
             
             
            Make sure to click through to the measurements page.

            From: mitch bucanon <maiky76@...>
            To: "regsaudioforum@yahoogroups.com" <regsaudioforum@yahoogroups.com>
            Sent: Friday, November 30, 2012 2:13 AM
            Subject: Re: [regsaudioforum] Re: Subwoofer distortion
             
             Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... 

             
            I have not listened to a Velodyne of recent vintage but the one I had around a while back surely did not seem to compress dynamically
            It uses feedback correction of driver motion but where is anything about dynamic compression?


            Sorry the forum seems acting weirdly but correct they use feedback but they do use a dynamic compressor example for the DD15 whether they like to call it that or not :
            http://t1.gstatic.com/images?q=tbn:ANd9GcSBE-frocFCo2VeGlrT8261Zy0YOegnkkY6vR5umnY7NGbO4E0ziuYswfc8-g
             
            Compressor: because the dynamic range of the output is not the same than the input (25dB input dynamic at 100Hz and only 7.5dB at 20Hz in the above example) that is by definition a compressor.
            Dynamic: because the compression varies with input: it is nonexistent at low level (the first lower 2/3 lines) and only kicks in at higher level.
            The amplifier will only deliver a fixed power to the driver at 20Hz regardless on the variation at the input ABOVE a certain threshold. At 110dB SPL the compression at 20Hz is 17.5dB and only 7.5dB at 100dB.
            Another example for the DD18: http://www.hometheater.com/images/archivesart/1004way.fig15.jpg
             
            Note that all sub/drivers/amplifier have a natural compression behavior anyways.
             
            But never mind Velodyne or Paradigm or xxx and complains about price and actual performances; the question still stands:
            If multi-sub is the way to go so what is the point of having a huge expensive underperforming sub when three/four smaller cheaper ones will trounce it in every respect?
             
            There is an alternative way :
            http://www.behringer.com/EN/Products/NU3000DSP.aspx
            DSP functions include a sophisticated delay for delay-line loudspeakers, crossover, EQ (eight parametric, two dynamic)
            Here are independent measurements:
            http://www.diyaudio.com/forums/class-d/213071-behringer-inuke-nu3000-measurements.html
             
            Buy:
            4 of the drivers I have mentioned for 1000USD (BTW these drivers are closely related to the ones in this thing: http://www.hometheater.com/content/way-down-deep-i-genelec-hts6 ;-)
            2 NU3000DSP for 800USD
            4 boxes top 1000USD (pick yours there http://www.parts-express.com/cat/subwoofer-speaker-cabinets/289) .
            Grand total 3000USD with bits and pieces so still comfortably under 5000USD of the DD18 (or the 10000USD for the Genelec HTS6)  and about the same price than the DD15.  
             
            With the formerly quoted paper (or Geddes method) http://www.harman.com/EN-US/OurCompany/Innovation/Documents/White%20Papers/multsubs.pdf
            This will achieve significantly better performance (no compression with more than 110dB SPL at 20Hz) better frequency smoothness even without EQing (that is also included anyway) 
            They come with a guaranty as well!
            Yes you lose the motional feedback offers but you don’t need it anymore since the 4 subs will have far less thermal compression and much lower THD anyway.
             
            If one is really serious about low THD at LF then one should seriously consider saving money and get better performance by actually putting into use the state of the art thing...
            M

            De : Robert <regtas43@...>
            À : regsaudioforum@yahoogroups.com
            Envoyé le : Vendredi 30 novembre 2012 13h17
            Objet : [regsaudioforum] Re: Subwoofer distortion
             
            I have not listened to a Velodyne of recent vintage but the one I had around a while back surely did not seem to compress dynamically It uses feedback correction of driver motion but where is anything about dynamic compression? REG PS I went to the first link and got almost nothing.. and I do not see anything about Paradigm on the second one.
            --- In mailto:regsaudioforum%40yahoogroups.com, mitch bucanon <maiky76@...> wrote: > > Hi, > > Have a look there: > http://www.avtalk.co.uk/showthread.php?t=12281 > and there: > http://www.hometheater.com/content/way-down-deep-i > Just make sure you have similar SPL to compare THD and vice-versa (have similar THD to compare SPL). > > Not the same standard but all subs can be compared  and you might reconsider this sentence: > "If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art." > > FYI Velodyne is using a dynamic compressor that limits the power sent to the driver at LF (hence the massive compression in the very botom end), so basicaly the THD will be fixed by the allowed value but the SPL will not increase whatever the input... Knowing that  > 1. higher THD might be such a big deal per se  > 2. at High SPL HD is less and less audible >    > Other will have higher THD, right, but higher SPL as well so... going with "whatever the THD how does it sounds is the point" argument you migh want to balance your argument. > I am no fanboy of Paradigm and 95dB at 20Hz @10% thd is OK for a consumer product but not ground breaking. > > From my experience a DIY sub (Sealed, 50L, with EQ) using this driver: > http://www.parts-express.com/pe/showdetl.cfm?partnumber=264-1114&utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=AskAndAnswer&utm_content=Default > Should have similar SPL at the very low end. > > Question though: if multi-sub is the way to go so what is the point of having a huge expensive sub when three smaller cheaper will trounce it in every respect? > > > With regard to the price and claims of constructors, well blame that on the society that prevent people from acquiring skepticism and the HIFI mags that promote magical accessories. > M    > > > ________________________________ > De : Robert <regtas43@...> > À : mailto:regsaudioforum%40yahoogroups.com > Envoyé le : Vendredi 30 novembre 2012 1h34 > Objet : [regsaudioforum] Re: Subwoofer distortion > > >   > This is truly fatuous in my opinion > as a justification for calling 10% low distortion. > The review was of a subwoofer that costs more than > $4000. No one should be thinking that it nice that it > is better than a lot of others--it darned > well better be better than the ones > that cost a lot less. And the product in question > is not claiming to be pretty good as cheap > subs go. It is claiming to be really good altogether. > And Velodyne has less expensive subs > that have much better distortion. > > What is all this? A Paradigm secret ad > campaign here? > > The "state of the art" is not set by > how bad things are on average but how > good they can be. > > The Paradigm does what it does--play really > loudly out of a rather small enclosure. > But the evidence offered does not suggest it > has really low distortion in terms of what > is available. > > Whether this matters is up to your decision. > But reviews should not mislead people. > > REG > > --- In mailto:regsaudioforum%40yahoogroups.com, Peter <alcomdata@> wrote: > > > > > Whether or not it matters > > audibly, 10 % distoriton is NOT low compared > > to what is available. It just is not. > > > > Of course it's not low in an absolute sense, and is rarely (if ever) tolerated in anything other than transducers under unusual conditions (except for tube amps, of course!) > >   > > But in relative terms?  If, say, 95% of subwoofers tested (using identical test methods) have THD more than 10% at 95 dB and 20 Hz, then 10% THD is actually getting fairly close to the state of the art. > > >
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