The "buzz" issue

evil_one · Nov 3, 2003, 02:46 PM

This applies only to 24 bit capable sound cards (also USB external devices) running under Windows XP or 2003. If you have such a sound card, you may have encountered it. Here's how it sounds like (may slightly vary from your system):
http://www.forgotten-realms.cfl.pl/o.../bin/noise.rar (turn your speakers down before playing!)

To test your system for this issue, download and extract this file:
http://www.forgotten-realms.cfl.pl/o...in/test48s.rar

I will use Winamp in this example, but any player that supports 24bit wav files should do. Make sure .wav files are associated with Winamp, and that the DirectSound output plugin is used, without any resampling and hardware acceleration enabled.
Then, first double click 24.wav, let it play for a while and double click 16.wav. If your system is affected, the noise will be heard (make sure to turn the speakers down... it's LOUD).

Now, this issue occurs when a 24bit (or 32 bit) file is played, playback is stopped (or paused), and then a file with the same or lower bit depth (8bit or 16bit) is played in a different session of the application (or even in the same session in case of Winamp). The sample rate can be the same or lower. Issue does not occur if: the second file has a higher sample rate than the first, if the first file played has a lower bit depth than the second and if both files are playing simultaneously.

I've traced the problem to Microsoft's kmixer.sys. Replacing that file with a version from an earlier OS solves it. I have found a recent (3 june 2003, v 5.0.2195.6752) version of kmixer.sys for Windows 2000 (it will also work with XP and 2003), wich eliminates this buzzing problem, but unfortunately, it doesn't support 192KHz (currently only Windows XP SP1 and 2003 support 192KHz). I doubt you have any true 192KHz recordings you play on your PC anyway.
http://www.forgotten-realms.cfl.pl/o...bin/kmixer.rar

To install it, replace the existing file in Windows\System32\Drivers (make a backup first!). Note that disabling Windows File Protection may be neccessary, but you may try to use the included batch file and quickly reboot the system afterwards. This should fool WFP. Make sure that the file has been replaced by checking it's version number (should be 5.0.2195.6752 after replacing).

I'd appreciate feedback from people who try this.

Also, if someone has a WinXP/2003 system with a 24bit capable sound card that is NOT affected, please post some information.

demalion · Nov 4, 2003, 08:05 PM

Tried it with DirectSound output, hardware acceleration off, using my Aureon soundcard and its latest drivers. Quite noticeable buzz. I don't usually use that method of playback, though, but it seems like something that should have some attention given to it.

evil_one · Nov 4, 2003, 09:47 PM

I've reported this to AUDIOTRAK, they are supposed to investigate and solve it (I don't see any other method of solving this than reporting to microsoft and demanding a kmixer.sys update from them), but I guess the more people report it to their cards manufacturers the better. I think bothering a MS tech support person about it would be useless, and contact information to any of the programmers inside is not avalible to me.

I wonder what sound cards are actually affected, all 24 bit capable or i.e. the ones that lack a hardware mixer (i.e. Envy24HT/PT based).

evil_one · Nov 4, 2003, 10:13 PM

Terratec has also been notified. Now a Revo owner should notify M-Audio...

evil_one · Nov 4, 2003, 11:13 PM

BTW there's no "real" hardware acceleration on the Envy24HT/PT based cards. If you enable this option when Sensaura is disabled, it'll have no effect, and when Sensaura is enabled, the stream mixing will be performend by the Sensaura driver instead of kmixer.sys, but still it's all done by the CPU.

RIV@NVX · Nov 6, 2003, 11:21 AM

Yeah, but I heard that Envy24 cards support 16 HW streams, and they are turned on only when Sensaura is enabled.

evil_one · Nov 6, 2003, 02:18 PM

Erm, no, Sensaura provides emulation of 64 hardware streams... They're really done in software, but all applications "see" 64 hardware accelerated streams.

Nov 3, 2003, 02:46 PM	#1
evil_one DriverHeaven Lover Join Date: Nov 2002 Posts: 109 Rep Power: 0	The "buzz" issue This applies only to 24 bit capable sound cards (also USB external devices) running under Windows XP or 2003. If you have such a sound card, you may have encountered it. Here's how it sounds like (may slightly vary from your system): http://www.forgotten-realms.cfl.pl/o.../bin/noise.rar (turn your speakers down before playing!) To test your system for this issue, download and extract this file: http://www.forgotten-realms.cfl.pl/o...in/test48s.rar I will use Winamp in this example, but any player that supports 24bit wav files should do. Make sure .wav files are associated with Winamp, and that the DirectSound output plugin is used, without any resampling and hardware acceleration enabled. Then, first double click 24.wav, let it play for a while and double click 16.wav. If your system is affected, the noise will be heard (make sure to turn the speakers down... it's LOUD). Now, this issue occurs when a 24bit (or 32 bit) file is played, playback is stopped (or paused), and then a file with the same or lower bit depth (8bit or 16bit) is played in a different session of the application (or even in the same session in case of Winamp). The sample rate can be the same or lower. Issue does not occur if: the second file has a higher sample rate than the first, if the first file played has a lower bit depth than the second and if both files are playing simultaneously. I've traced the problem to Microsoft's kmixer.sys. Replacing that file with a version from an earlier OS solves it. I have found a recent (3 june 2003, v 5.0.2195.6752) version of kmixer.sys for Windows 2000 (it will also work with XP and 2003), wich eliminates this buzzing problem, but unfortunately, it doesn't support 192KHz (currently only Windows XP SP1 and 2003 support 192KHz). I doubt you have any true 192KHz recordings you play on your PC anyway. http://www.forgotten-realms.cfl.pl/o...bin/kmixer.rar To install it, replace the existing file in Windows\System32\Drivers (make a backup first!). Note that disabling Windows File Protection may be neccessary, but you may try to use the included batch file and quickly reboot the system afterwards. This should fool WFP. Make sure that the file has been replaced by checking it's version number (should be 5.0.2195.6752 after replacing). I'd appreciate feedback from people who try this. Also, if someone has a WinXP/2003 system with a 24bit capable sound card that is NOT affected, please post some information. Last edited by evil_one; Nov 3, 2003 at 02:55 PM.

Nov 4, 2003, 08:05 PM	#2
demalion ={DH}=demalion Join Date: Dec 2002 Posts: 0 Rep Power: 0	Yes, I heard the buzz Tried it with DirectSound output, hardware acceleration off, using my Aureon soundcard and its latest drivers. Quite noticeable buzz. I don't usually use that method of playback, though, but it seems like something that should have some attention given to it.

Nov 6, 2003, 11:21 AM	#6
RIV@NVX Freedom is a feature. Join Date: Jul 2002 Location: Croatia, Rijeka Posts: 4,476 Rep Power: 67 System Specs	Yeah, but I heard that Envy24 cards support 16 HW streams, and they are turned on only when Sensaura is enabled. __________________ -- Vedran

Nov 4, 2003, 09:47 PM	Thread Starter #3
evil_one DriverHeaven Lover Join Date: Nov 2002 Posts: 109 Rep Power: 0	I've reported this to AUDIOTRAK, they are supposed to investigate and solve it (I don't see any other method of solving this than reporting to microsoft and demanding a kmixer.sys update from them), but I guess the more people report it to their cards manufacturers the better. I think bothering a MS tech support person about it would be useless, and contact information to any of the programmers inside is not avalible to me. I wonder what sound cards are actually affected, all 24 bit capable or i.e. the ones that lack a hardware mixer (i.e. Envy24HT/PT based).

Nov 4, 2003, 10:13 PM	Thread Starter #4
evil_one DriverHeaven Lover Join Date: Nov 2002 Posts: 109 Rep Power: 0	Terratec has also been notified. Now a Revo owner should notify M-Audio...

Nov 4, 2003, 11:13 PM	Thread Starter #5
evil_one DriverHeaven Lover Join Date: Nov 2002 Posts: 109 Rep Power: 0	BTW there's no "real" hardware acceleration on the Envy24HT/PT based cards. If you enable this option when Sensaura is disabled, it'll have no effect, and when Sensaura is enabled, the stream mixing will be performend by the Sensaura driver instead of kmixer.sys, but still it's all done by the CPU.

Nov 6, 2003, 02:18 PM	Thread Starter #7
evil_one DriverHeaven Lover Join Date: Nov 2002 Posts: 109 Rep Power: 0	Erm, no, Sensaura provides emulation of 64 hardware streams... They're really done in software, but all applications "see" 64 hardware accelerated streams.