#9641 BLOC 1.5-sof: test XO-1.5 audio recording levels

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#9641: test XO-1.5 audio recording levels
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           Reporter:  dsd      |       Owner:  Quozl                            
               Type:  task     |      Status:  reopened                         
           Priority:  blocker  |   Milestone:  1.5-software-later               
          Component:  kernel   |     Version:  Development build as of this date
         Resolution:           |    Keywords:                                   
        Next_action:  review   |    Verified:  0                                
Deployment_affected:           |   Blockedby:  9639                             
           Blocking:           |  
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Changes (by Quozl):

  * status:  closed => reopened
  * next_action:  testcase => review
  * resolution:  fixed =>


Comment:

 I cannot tell if gstreamer, or therefore Record, use the same levels, but
 the following test suggests they do.

 gstreamer cannot properly record audio on XO-1.5 by default, so a
 comparison is not as trivial as with arecord.  The following pipeline
 generates incorrect audio on the XO-1.5:

 {{{
 gst-launch alsasrc ! waveenc ! filesink location=/tmp/test.wav
 }}}

 However, the ''plughw'' workaround works:

 {{{
 gst-launch alsasrc device=plughw:0,0 ! waveenc ! filesink
 location=/tmp/test.wav
 }}}

 Eight brief notes, and then a two second burst were played on the musical
 instrument.  The recordings were then analysed using Audacity 1.3.11 on a
 desktop system.

 The XO-1.5 C1 recording suffered from a DC offset (#9851) that had to be
 removed before rms volume analysis.

 The Contrast Analyzer for WCAG 2 compliance was used to measure the rms
 volume of the two second burst against the two second silence that
 followed.

 ||''model''||''burst volume''||''silence volume''||
 ||XO-1.5 C1||-27.4 dB||-62.4 dB||
 ||XO-1||-25.1 dB||-60.0 dB||

 Conclusion: there is a 2 dB difference; the XO-1 generates a recording
 that has slightly louder than the XO-1.5.

 Risk: there may be significant manufacturing variability that more than
 compensates for this observation.  I've no idea what the manufacturing
 test criteria are.

-- 
Ticket URL: <http://dev.laptop.org/ticket/9641#comment:11>
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