Re: Trasients when playing silence with Matlab (Sylvain Choisel )

Subject: Re: Trasients when playing silence with Matlab From: Sylvain Choisel <SYC@xxxxxxxx> Date: Fri, 8 Feb 2008 08:55:29 +0100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY> This is a multipart message in MIME format. --=_alternative 002B8809C12573E9_= Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Enrique, If you want to exclude the possibility that these clicks come from Windows = (if that is the OS you are using), I suggest you try the user-contributed function=20 "pa=5Fwavplay" that makes=20 use of the ASIO drivers. It has the advantage of bypassing the Windows=20 sound mixer.=20 You can find this function here: http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=3D= 4017&objectType=3Dfile Another source of clicks is a change of sampling frequency, that will=20 cause the soundcard=20 to loose the clock for a short while. Check the clock settings in the=20 sound card's control panel, you can monitor the current sampling frequency, and see if it changes at=20 the same time as you hear the click.=20 Best regards, Sylvain AUDITORY - Research in Auditory Perception <AUDITORY@xxxxxxxx>=20 wrote on 07/02/2008 17:25:40: > Dear Enrique, >=20 > the issue your are experiencing may come from many things. I would=20 > suggest you to try with a different soundcard first to discard the=20 > soundcard issue. >=20 > Then, Matlab does not handle sound cards directly, but rather uses some=20 > OS calls. So your issue may also come from your operating system (Linux, = > Mac OS X, ...). If you replicate the same behavior with a different=20 > soundcard, I would suggest to contact Matlab support directly with a=20 > complete description of your issue with code, they usually answer in a=20 > day or two. >=20 > That said, I know that the command "sound" is very brittle on many OSes. = > You can try the "audioplayer" that uses JAVA calls and may behave better = > for your purpose (type "doc audioplayer" in your Matlab command prompt=20 > for usage). >=20 > Cheers, >=20 > Mathieu Lagrange > Lopez-Poveda, Enrique A. a =E9crit : > > Dear friends, > > > > Here is a technical question on a problem that is driving us crazy. > > > > We want to play sounds from Matlab through an RME Fireface 400 sound=20 > > card. The problem is that when we play a "silence" interval (array of=20 > > zeros) we can hear (and even record) a clear transient at the onset of = > > the =5Fsilence=5F signal. We would very much like to get rid of that on= set=20 > > transient. Any cues as to how to get rid of it? > > > > Thank you so much in advance. > > > > - Enrique > > > > Enrique A. Lopez-Poveda, Ph.D. > > Instituto de Neurociencias de Castilla y Le=F3n > > Universidad de Salamanca > > Av. Alfonso X El Sabio S/N, 37007 Salamanca, Spain. > > Phone: (+34) 923 294 500 ext. 1957 > > Fax: (+34) 923 294 750 > > E-mail: ealopezpoveda@xxxxxxxx > > http://web.usal.es/~ealopezpoveda/=20 >=20 --=_alternative 002B8809C12573E9_= Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Enrique, If you want to exclude the possibili= ty that these clicks come from Windows (if that is the OS you are using), I suggest you try the user-contributed function "pa=5Fwavplay" that makes use of the ASIO drivers.  It has the advantage of bypassing the Windows sound mixer. You can find this function here:</fo= nt> http://www.mathworks.com/matlabcentr= al/fileexchange/loadFile.do?objectId=3D4017&objectType=3Dfile Another source of clicks is a change of sampling frequency, that will cause the soundcard to loose the clock for a short while. Check the clock settings in the sound card's control panel, you can monitor the current sampling frequency, and see if it changes at the same time as you hear the click. Best regards, Sylvain <tt>AUDITORY - Research in Auditory Perception <AUDIT= ORY@xxxxxxxx> wrote on 07/02/2008 17:25:40: > Dear Enrique, > > the issue your are experiencing may come from many things. I would > suggest you to try with a different soundcard first to discard the > soundcard issue. > > Then, Matlab does not handle sound cards directly, but rather uses some > OS calls. So your issue may also come from your operating system (Linu= x, > Mac OS X, ...). If you replicate the same behavior with a different > soundcard,  I would suggest to contact Matlab support directly with a > complete description of your issue with code, they usually answer in a > day or two. > > That said, I know that the command "sound" is very brittle on many OSes. > You can try the "audioplayer" that uses JAVA calls and may behave better > for your purpose (type "doc audioplayer" in your Matlab command prompt > for usage). > > Cheers, > > Mathieu Lagrange > Lopez-Poveda, Enrique A. a =E9crit : > > Dear friends, > > > > Here is a technical question on a problem that is driving us crazy. > > > > We want to play sounds from Matlab through an RME Fireface 400 sound > > card. The problem is that when we play a "silence" interval (array of > > zeros) we can hear (and even record) a clear transient at the onset of > > the =5Fsilence=5F signal. We would very much like to get rid of t= hat onset > > transient. Any cues as to how to get rid of it? > > > > Thank you so much in advance. > > > > - Enrique > > > > Enrique A. Lopez-Poveda, Ph.D. > > Instituto de Neurociencias de Castilla y Le=F3n > > Universidad de Salamanca > > Av. Alfonso X El Sabio S/N, 37007 Salamanca, Spain. > > Phone: (+34) 923 294 500 ext. 1957 > > Fax: (+34) 923 294 750 > > E-mail: ealopezpoveda@xxxxxxxx > > http://web.usal.es/~ealopezpoveda/ > </tt> --=_alternative 002B8809C12573E9_=--

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Electrical Engineering Dept., Columbia University