#5645 NORM Update.: TamTam crackling noise problem

[Zarro Boogs per Child]

#5645: TamTam crackling noise problem
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 Reporter:  wolfgang                    |       Owner:  Nat     
     Type:  defect                      |      Status:  new     
 Priority:  normal                      |   Milestone:  Update.1
Component:  tamtam-activity             |     Version:          
 Keywords:  TamTam ALSA Clooper CSound  |    Verified:  0       
 Blocking:                              |   Blockedby:          
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 == Background: ==

 We are preparing the next release of our XO-LiveCD which is scheduled
 to be released shortly after the official release of update.1 and will be
 based on the latest official devel-ext3 image build.

 One of the serious problems, which makes it difficult for us to
 introduce the XO-LiveCD in primary schools, is a problem related to
 TamTam Sound.



 == Problem Description ==



 There is an annoying crackling background noise when you start
 any TamTam activity. The noise sounds like a rectangular wave signal
 with a frequency of approximately 20 Hz, played at maximum volume.
 We have attached a recorded sound sample to this ticket.

 The problem exits since we tried TamTam the first time (started with build
 625). It is reproducible on certain hardware but seems to depend on
 hardware and/or ALSA sound driver.

     * the problem occurs at about 80% of sound hardware we have
       investigated. In most cases the noise appears only on the right
       audio channel and the left channel works with normal sound
       output.

     * in about 10% there is no problem, TamTam work fine

     * on some hardware TamTam is silent, this problem could be related
       but is not the object of this ticket

 In all cases sound works well for activities NOT using Clooper/Csound
 like ETOYS and PIPPY. It also works if you play any sound file by aplay.
 When you generate a sound file by one of the numerous csound CSD examples
 and play it with aplay, it sounds good too.

 Based on information and hints we found in Ticket 1978 - TamTam is
 silent under qemu - we already tried several settings of PLUGIN_RATE in
 Config.py, turned on DEBUGGING but without any success yet.

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Ticket URL: <http://dev.laptop.org/ticket/5645>
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