blog/data/2018-10-22-audmes-measure-speakers.txt

   1 Title: Measuring the speaker frequency response using the AUDMES free software GUI - nice free software
   2 Tags: english, nice free software
   3 Date: 2018-10-22 08:40
   4
   5 <p><img src="http://people.skolelinux.org/pere/blog/images/2018-10-22-audmes-measure-speakers.png" align="right" width="40%"/></p>
   6
   7 <p>My current home stereo is a patchwork of various pieces I got on
   8 flee markeds over the years.  It is amazing what kind of equipment
   9 show up there.  I've been wondering for a while if it was possible to
  10 measure how well this equipment is working together, and decided to
  11 see how far I could get using free software.  After trawling the web I
  12 came across an article from DIY Audio and Video on
  13 <a href="https://www.diyaudioandvideo.com/Tutorial/SpeakerResponseTesting/">Speaker
  14 Testing and Analysis</a> describing how to test speakers, and it listing
  15 several software options, among them
  16 <a href="https://sourceforge.net/projects/audmes/">AUDio MEasurement
  17 System (AUDMES)</a>.  It is the only free software system I could find
  18 focusing on measuring speakers and audio frequency response.  In the
  19 process I also found an interesting article from NOVO on
  20 <a href="http://novo.press/understanding-speaker-specifications-and-frequency-response/">Understanding
  21 Speaker Specifications and Frequency Response</a> and an article from
  22 ecoustics on
  23 <a href="https://www.ecoustics.com/articles/understanding-speaker-frequency-response/">Understanding
  24 Speaker Frequency Response</a>, with a lot of information on what to
  25 look for and how to interpret the graphs.  Armed with this knowledge,
  26 I set out to measure the state of my speakers.</p>
  27
  28 <p>The first hurdle was that AUDMES hadn't seen a commit for 10 years
  29 and did not build with current compilers and libraries.  I got in
  30 touch with its author, who no longer was spending time on the program
  31 but gave me write access to the subversion repository on Sourceforge.
  32 The end result is that now the code build on Linux and is capable of
  33 saving and loading the collected frequency response data in CSV
  34 format.  The application is quite nice and flexible, and I was able to
  35 select the input and output audio interfaces independently.  This made
  36 it possible to use a USB mixer as the input source, while sending
  37 output via my laptop headphone connection.  I lacked the hardware and
  38 cabling to figure out a different way to get independent cabling to
  39 speakers and microphone.</p>
  40
  41 <p>Using this setup I could see how a large range of high frequencies
  42 apparently were not making it out of my speakers.  The picture show
  43 the frequency response measurement of one of the speakers.  Note the
  44 frequency lines seem to be slightly misaligned, compared to the CSV
  45 output from the program.  I can not hear several of these are high
  46 frequencies, according to measurement from
  47 <a href="http://freehearingtestsoftware.com">Free Hearing Test
  48 Software</a>, an freeware system to measure your hearing (still
  49 looking for a free software alternative), so I do not know if they are
  50 coming out out the speakers.  I thus do not quite know how to figure
  51 out if the missing frequencies is a problem with the microphone, the
  52 amplifier or the speakers, but I managed to rule out the audio card in my
  53 PC by measuring my Bose noise canceling headset using its own
  54 microphone.  This setup was able to see the high frequency tones, so
  55 the problem with my stereo had to be in the amplifier or speakers.</p>
  56
  57 <p>Anyway, to try to role out one factor I ended up picking up a new
  58 set of speakers at a flee marked, and these work a lot better than the
  59 old speakers, so I guess the microphone and amplifier is OK.  If you
  60 need to measure your own speakers, check out AUDMES.  If more people
  61 get involved, perhaps the project could become good enough to
  62 <a href="https://bugs.debian.org/910876">include in Debian</a>?  And if
  63 you know of some other free software to measure speakers and amplifier
  64 performance, please let me know.  I am aware of the freeware option
  65 <a href="https://www.roomeqwizard.com/">REW</a>, but I want something
  66 that can be developed also when the vendor looses interest.</p>
  67
  68 <p>As usual, if you use Bitcoin and want to show your support of my
  69 activities, please send Bitcoin donations to my address
  70 <b><a href="bitcoin:15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b">15oWEoG9dUPovwmUL9KWAnYRtNJEkP1u1b</a></b>.</p>