Weird freq response due to Win 7 ?

percy · 8th March 2010, 11:04 PM

Audigy 2 NX USB soundcard. Just for kicks hooked it up to my new laptop that has Windows 7 and did some measurements. I am having a very strange and weird issue with it.

The issue is that the frequency response of the card when recording only (playback is fine) has a series of huge (+12 to 18db!) peaks. I also see a sort of pattern to these giant peaks. They seem to be odd multiples of 1100hz.

What could this be ? Is there anyting about Win 7 or the soundcard drivers ?

I have used/measured this soundcard on a XP desktop and it has worked just fine.
Any ideas ? Has anyone experienced such a thing with any soundcards on Win 7 ?

human.bin · 11th March 2010, 12:26 AM

first download latest drivers, than try going trough WASAPI if possible

percy · 11th March 2010, 12:58 AM

how does one 'go through WSAPI' ?

5th element · 11th March 2010, 01:14 AM

Quote:

Originally Posted by percy

how does one 'go through WSAPI' ?

This would be program dependant. For example Foobar 2k has a component that allows you to use WASAPI as the output. This isn't something typically supported by a lot of programs, they usually use ASIO if anything. WASAPI is another way to bypass the windows mixer and any software re-sampling windows might be doing.

I've been having no problems with windows 7 when it comes to my PCI sound card. With the PCM2706 USB chip I had no problems either.

One thing that it could be is an inconsistency somewhere with the sampling frequency. You should be able to alter this in the 'Sound' tab in the control panel. Make sure the program your using is set to use same sampling frequency that the card is set to.

I know that if I've got 96khz selected and I try to do a FR sweep at 48khz or similar I get deviations in the frequency response.

percy · 17th March 2010, 03:25 AM

I figured this out. It was due to the Line In volume in the "playback" mixer settings. When I muted it, everything worked just fine. Must be creating some sort of an internal loopback and causing strange feedback. All is well now!

Rembrant · 22nd March 2010, 03:38 AM

I installed the WASAPI plugin for foobar2000 and I certainly hear a large difference. I'm not really sure what windows was doing, but now everything sounds much better.

Output data format is set to 24bit.

8th March 2010, 11:04 PM	#1
percy diyAudio Member Join Date: Apr 2004 Location: MN	Weird freq response due to Win 7 ? Audigy 2 NX USB soundcard. Just for kicks hooked it up to my new laptop that has Windows 7 and did some measurements. I am having a very strange and weird issue with it. The issue is that the frequency response of the card when recording only (playback is fine) has a series of huge (+12 to 18db!) peaks. I also see a sort of pattern to these giant peaks. They seem to be odd multiples of 1100hz. What could this be ? Is there anyting about Win 7 or the soundcard drivers ? I have used/measured this soundcard on a XP desktop and it has worked just fine. Any ideas ? Has anyone experienced such a thing with any soundcards on Win 7 ?

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11th March 2010, 12:26 AM	#2
human.bin diyAudio Member Join Date: May 2008	first download latest drivers, than try going trough WASAPI if possible

11th March 2010, 12:58 AM	#3
percy diyAudio Member Join Date: Apr 2004 Location: MN	how does one 'go through WSAPI' ?

17th March 2010, 03:25 AM	#5
percy diyAudio Member Join Date: Apr 2004 Location: MN	I figured this out. It was due to the Line In volume in the "playback" mixer settings. When I muted it, everything worked just fine. Must be creating some sort of an internal loopback and causing strange feedback. All is well now!

22nd March 2010, 03:38 AM	#6
Rembrant diyAudio Member Join Date: Mar 2007	I installed the WASAPI plugin for foobar2000 and I certainly hear a large difference. I'm not really sure what windows was doing, but now everything sounds much better. Output data format is set to 24bit.