Compatibility Issues with PRAXIS

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PRAXIS is designed to work with general Windows hardware and drivers and assumes that these will comply with Windows API standards and provide proper data communications.  With the vast number of different devices and the combinations possible with these which are possible, issues are bound to come up in both Windows and in Praxis.  

Please recognize that compatibility issues, beyond our control, can occur between computer motherboards, device drivers, USB ports, and soundcards and other peripherals.  While we try to test PRAXIS with various operating systems and  recommended soundcards under many configurations, we still cannot begin to cover even a small fraction of all the possible combinations and thus cannot guarantee that all combinations will be usable. (No other measurement systems, not even ones using specially designed interface hardware can guarantee this either!)

See also some recently documented Soundcard Calibration Case Histories.

This page is provided as a collection point for known or reported issues, (or related tips) for various soundcards, motherboards, and chipsets.

• The Conexant "RipTide" audio (or audio/modem combination) will NOT work with PRAXIS, as it has lacks stereo recording capability. 
  
• Soundblaster Audigy: We have seen mention that this card is unable to easily disable record monitoring into playback, which would prevent use in measurement systems.  See this PDF file from Creative Labs for a technique that should solve this.
  
  Also, Dave Hamaker, on comp.sys.ibm.pc.soundcard.rec, posted the following possible workaround:
  "You can mute playback of the analog mix by using a custom EAX Control panel preset.  You might start with the "(No Effects)" preset.  Then go to the "Source" tab.  Select the Analog Mix source.  Now select each effect, _including_ Original Sound, and lower the amount to 0.  You probably should save the altered preset under a new name for reuse.
  
• Soundblaster Live, Soundblaster 128 PCI, Ensoniq PCI cards: Cannot be used in "synchronous" operation except at 48kHz and 24kHz sample rates. This does not affect Chirp or "Resynch MLS" type measurements. There is a simple workaround for this situation: just use 48kHz or 24kHz for measurements.  It should be noted that synchronous techniques in Praxis are seldom necessary, except perhaps for tone bursts, and in any cases can still be done at the 48kHz rate without problem..  Be sure that all monitoring functions or 3D audio functions are disabled.  We no longer suggest the "Soundblaster 128" soundcards, as some boards sold under this name use a different chipset ("Vibra") and would not calibrate in at least one system. 
  
• Creative Labs Cards in general:  Creative Labs has a tendency to sell different kinds of hardware under the same brand or model name.  This makes it impossible for us to be sure that our PRAXIS setups and operations correspond to every variety of soundcard that is sold under a given brand name from this manufacturer.  
  
• VIA VT82C686, 686a, 686b... Southbridge chip:  This chip is used on many "KT133A" motherboards with Athlon processors.  The 686b has become somewhat infamous for problems with PCI soundcards, particularly (but not exclusively) with the Soundblaster Live.  In normal soundcard use, the problem is usually manifested as scratchiness, clicks, or pops during playback of wav files -- irritating, but tolerable for most computer uses, but a serious problems if you are making measurements or recording. The issue may be related to a bug that causes hard disk drive corruption in some systems.  The problem is not universal, and many owners of motherboards using 686 processors report having no audio problems.
  
  Various fixes have been announced, with some users reporting success, others not.  The problem may be an issue of tolerances.  Some people have no problems at all.  But at least one PRAXIS user was not able to clear it up in a 686a equipped  motherboard, (even after re-flashing the BIOS, moving cards around, swapping interrupts, changing drivers, changing soundcard brand, installing patches, etc) -- UNTIL he changed motherboards (and to an Intel Celeron setup), then all behaved properly.  If you are getting a new motherboard for audio use, it may be wise to avoid the VIA 686 chip.  

see VIA's page on the subject  http://www.viahardware.com/686b_1.shtm

see the German Au-Ja site, for some technical details: http://www.au-ja.org/review-kt133a-1-en.phtml

Or for further reading, try the following google search:  http://www.google.com/search?q=VIA+SouthBridge+bug&hl=en&start=30&sa=N

Or more related links:
http://www.tech-report.com/news_reply.x/2587/3/
http://www.sound-music.com/guillemot/isis_faq.htm
http://service.steinberg.net/knowledge.nsf/show/pc_projectcard_viachipset

• Onkyo SE-U55: This well-built and inexpensive USB sound device unfortunately will not work with Praxis.  This is because the device has hardwired monitoring of the record signal into the playback signal (anything being input to the card also appears at its line output jacks).  It's a real shame that such a nicely-made hardware unit should be crippled by such a shortsighted conceptual design!  Wake up, Onkyo!