Comments on: An audiophile’s look at the audio stack in Windows Vista and 7 http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/ Things I've learned, published for the public benefit Sat, 04 Feb 2012 08:39:24 +0000 hourly 1 http://wordpress.com/ By: Robert Halvarsson http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-1164 Wed, 28 Dec 2011 22:00:02 +0000 http://blog.szynalski.com/?p=148#comment-1164 Apparantly Microsoft is aware of the problem, yet I had hopes that this would be fixed by now. I am personally affected, and even though I can remedy the problem by decreasing the khz manually, I know a lot of people who don’t…

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-961 Wed, 26 Oct 2011 11:15:50 +0000 http://blog.szynalski.com/?p=148#comment-961 GoukI,
That’s good that it is working well for you, however, there is definitely a problem – Microsoft have admitted it. Please refer to the MSDN forum thread above (again – the link is http://social.msdn.microsoft.com/Forums/en/windowspro-audiodevelopment/thread/725546ce-57bf-40d0-b7aa-47e51de9c3ae ) The post from Microsoft is timestamped “Tuesday, March 29, 2011 3:56 PM”

The problem seems to ONLY affect applications that use the WaveOut API, just as our host Tomasz had concluded. ;^)

Greg.

]]> By: G0ukI http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-954 Tue, 25 Oct 2011 10:58:53 +0000 http://blog.szynalski.com/?p=148#comment-954 My post is a little late in the day, but I stumbled across this article and simply had to throw in my thoughts as an audiophile sound engineer with a lot of time on his hands!
I currently have my onboard soundcard set to 96khz 24bit, using Media Player Classic FFDshow Audio Decoder to resample audio to 96khz libavcodec highest quality, with the ouput format for uncompressed or decoded streams set to 32bit floating point and nothing else. The upshot of this is that decent quality mp3′s now sound more ‘airy’ and the bottom end more natural and deep – they no longer sound like crunchy mp3′s! That, and it’s also possible to select which applications then use these settings in Directshow control, so it’s possible to apply these settings to Youtube videos, etc.
Technically I know I’m out of my depth regarding this article, however, I have spent extensive time testing different configurations to acheive the highest possible audio quality in Windows 7 with minimum perceived artifacts using this player and am more than satisfied with the results.
It took a quite a while and a lot of testing to work out how to configure Media Player Classic to achieve this, but now it’s working the way it should, it sounds like I’ve have a far superior soundcard! :)

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-596 Mon, 03 Jan 2011 22:32:06 +0000 http://blog.szynalski.com/?p=148#comment-596 I have cross posted about the sample rate conversion quality issue in a few places, one of them being the Microsoft Pro Audio Developer’s Forum:

http://social.msdn.microsoft.com/Forums/en/windowspro-audiodevelopment/thread/725546ce-57bf-40d0-b7aa-47e51de9c3ae

Greg.

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-594 Mon, 03 Jan 2011 15:15:35 +0000 http://blog.szynalski.com/?p=148#comment-594 Tomasz,
I did some testing with Winamp.I verified that it behaves the same as yours on Windows 7. (no distortion with Directsound, distortion with WaveOut).

I then tested it on Windows XP. I first opened another Directsound application, to lock the hardware at 48kHz. I then opened Winamp, and played a 44.1kHz test tone, using WaveOut. There was no distortion. I used the USB interface so I could monitor the actual sample rate of the hardware – it stayed on 48kHz the entire time.

So, as I suspected, WaveOut appears to perform good quality sample rate conversion on Windows XP.

Greg.

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-593 Mon, 03 Jan 2011 13:14:59 +0000 http://blog.szynalski.com/?p=148#comment-593 Thanks!

On Windows XP, it seems that even WaveOut works ok.

Now, is there any way to configure YouTube to use Directsound on Windows 7?

Greg.

]]> By: Tomasz http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-592 Mon, 03 Jan 2011 13:10:26 +0000 http://blog.szynalski.com/?p=148#comment-592 I generated a 40 Hz tone in Cool Edit Pro, both in 44.1 kHz and 48 kHz. Whenever the sample rate doesn’t match the Windows sample rate, I hear the same high-frequency distortion artifact.

Here are the results of playing a 44.1 kHz WAV file (40 Hz tone) in various apps with the Windows sample rate set to 48 kHz:

Cool Edit Pro 2.0 – distortion
Windows Media Player – no distortion
Foobar2000 – no distortion
iTunes 7 – no distortion
Winamp (with Directsound output) – no distortion
Winamp (WaveOut output) – distortion

In short, Directsound output upsamples correctly. WaveOut produces distortion.

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-588 Mon, 03 Jan 2011 12:25:07 +0000 http://blog.szynalski.com/?p=148#comment-588 I’ve reproduced the problem with a high quality USB audio interface. (the M-Audio Fast Track Ultra). The nice thing about this interface is that it has it’s own control panel, so I can be sure of the actual sample rate being used at any given time.

Windows 7 honours whatever sample rate I set in the M-Audio control panel – all formats available in Windows are restricted to the M-Audio sample rate. So, again, when I play back 44.1kHz material when the M-Audio interface is set to 48kHz, I hear aliasing, either in YouTube, or when using the MMSys WAV driver in the Multistream ASIO player.

The standard Windows Media Player does NOT produce aliasing, so that’s encouraging. I also tried the Media Player Classic player, and it too worked fine, no matter what output renderer I chose.

I’ve also done some testing on Windows XP. Before I did the tests, I set the sample rate conversion quality to the LOWEST setting. In a nutshell, I am unable to get XP to produce aliasing. If only one application is open, Windows will set the audio interface to the same sample rate as the content.
If more than one application is open simultaneously, XP seems to leave the hardware configured to the rate that the first application set it to, and then, presumably, perform sample rate conversion. (I made sure that the second application was not simply outputting at the rate of the first application, by comparing pitches of test tones) Even when I open the Multistream player (which seems to use a sample rate of 44.1kHz for the test tone generator) when another app is holding the hardware rate at 48kHz, and then use MMSys WAV, the result is STILL clean! (it is clean when using DirectX as well) So, Windows XP seems to be behaving a lot better than Windows 7!

As an interesting aside, I am unable to get the VLC player to play a test tone cleanly, regardless of all the settings, but ONLY on Windows 7. On XP, it works fine. (?!)

Greg.

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-587 Mon, 03 Jan 2011 04:31:56 +0000 http://blog.szynalski.com/?p=148#comment-587 I found this YouTube clip of a 40Hz to 100Hz test tone:

With my interface set to 48kHz, the aliasing is very noticable.

I tried a test with a program that can generate test tones, and has multiple audio driver options. It supports ASIO, DirectX, and “MMSys WAV”.
When using MMS WAV I hear aliasing, but when I use ASIO or DirectX, I do NOT hear aliasing. The program is “Multistream ASIO Player”: http://www.tropicalcoder.com/MStreamPlayer.htm I will contact the author to see whether he can shed any light on this problem.

It’s conceivable that some apps, if they determine that they do not have exclusive access to the audio interface, and thus cannot change it’s sample rate to match the content, will perform their own sample rate conversion.

Note that I am doing this testing on a netbook running Windows 7 Starter Edition. I wonder whether Windows automatically improves the sample rate conversion if it detects a faster processor and/or a higher grade of Windows?
Greg.

]]> By: Greg Sullivan http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/#comment-586 Sat, 01 Jan 2011 11:48:16 +0000 http://blog.szynalski.com/?p=148#comment-586 I agree that the sample rate conversion is not very good. In Windows XP, there was a setting to control the quality of the conversion. I can’t find an equivalent setting in Windows 7. (anyone?) In XP, and on my particular system, it’s available at:
Control Panel | Sounds and Audio Devices Properties | Audio | Sound Playback | Advanced | Performance | Sample Rate Conversion Quality

Does it depend on the specific audio interface & driver?

I noticed the poor conversion quality immediately when I played a YouTube clip in Windows 7. When I changed the sample rate of the audio interface from 48kHz to 44.1kHz, the problem went away.

Greg.

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