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Fidelity problem on Windows 7 if sample rates do not match.

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  • sullivang
    replied
    Good news. It IS changing the hardware sample rate on Windows XP, but only as long as the requested rate is supported by the hardware. If it isn't, it seems to remain unchanged.
    I can only assume that I had entered one or more unsupported sample rates.

    It would be good if SoundCheck alerted the user if the requested rate was not supported by the hardware. I'm not saying that it should never allow unsupported rates, because it may be required to test the driver's ability to perform sample rate conversion.

    I've re-tested on Windows 7, and I can reaffirm that it NEVER changes the hardware rate. The hardware stays on the sample rate that is set in the Windows device advanced properties.

    Greg.

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  • sullivang
    replied
    I repeated the test on Windows XP, and it STILL didn't change the sample rate of the hardware! Arrghh. (I used a USB interface for the test, because it has it's own control panel, and I can monitor the sample rate that it is set to).

    I then tried another sound card test program (a very popular one, it seems), and that did work the way I would want it to - it did change the sample rate of the hardware whenever I changed it in the program.

    So, I was wrong. It is not AS common on Windows XP for the hardware to be automatically configured to match the audio, as I thought it was.

    Greg.

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  • sullivang
    replied
    I just did a test to prove that my concern is valid.

    In Windows, I set the sample rate to 48000.
    In SoundCheck, I set the sample rate to be 44100.

    I then played a sine wave test tone, and viewed the spectrum of the input. (I used a loopback cable).

    The input had additional frequencies, other than the frequency of the test tone, DUE TO THE RESAMPLING OF WINDOWS.

    I then changed the sample rate in Windows to match SoundCheck.

    THE RESULT WAS A VERY CLEAN SPECTRUM.

    Btw, this is a nice program. It's good being able to view the spectrum in real time.

    Greg.

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  • sullivang
    replied
    Ok.

    Just one other thing.

    Your wording in the FAQ is not strong enough IMHO. The fact is that SoundCheck ALWAYS uses what you refer to as the "shared mode" settings. No matter what the user enters into SoundCheck, the hardware will be configured to however it is in the "shared mode" settings. It wasn't like this back on XP, but that's how it is now.

    I referred to this blog indirectly in my first post, but I want to refer to it directly now:
    http://blog.szynalski.com/2009/11/17/an-audiophiles-look-at-the-audio-stack-in-windows-vista-and-7/
    It has some very important information. (says basically what I have been saying, because that's where I got the information to begin with, however I think it's worth a read, nevertheless)

    Greg.
    Last edited by sullivang; 01-10-2011, 11:22 AM.

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  • David (PassMark)
    replied
    We only make about $50 in sales per month for SoundCheck. Which means about $20 in profit before any support costs. So writing this post has blown the development budget on this product for this month

    A re-write of the software would mean 10 years or more of sales to recover the development costs. More profitable to leave the money in the bank, or invest in a more popular product.

    While it might not be ideal it is easier to change the setting in Windows as required.

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  • sullivang
    replied
    Soloing1: That's good news - well done.

    Passmark: Thanks for updating the FAQ. I really think that the application needs to be updated though, AT LEAST so that it warns the user to check that the sample rate in the Windows audio settings matches that in SoundCheck. The issue here is that it is theoretically possible that the sample rates will not match, yet the program could run smoothly, and everything will sound ok. However, if the user is going to analyse the recordings, the results may reflect the quality (or lack thereof!!) of the Windows sample rate conversion, rather than the capabilities of the audio interface. Another problem is that when the sample rates do not match, this also causes the frequency response to be that of the LOWEST link in the chain. So, if the user enters 96000 into SoundCheck, but the Windows sample rate is 44100, the upper frequency will only be 22050Hz, when it should be 48kHz! The user may be totally unaware of all this. It is a BIG change in behaviour in Windows.

    It would also be great if you could support different audio APIs, such as DirectSound, ASIO, and there's some new one called "WSAPI". Of course, it would also be good if you could have SoundCheck change the sample rate (and bit depth) of the audio hardware to match the settings that the user enters into SoundCheck, or at least provide the OPTION for this.

    Greg.

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  • David (PassMark)
    replied
    Just as a follow up for this,

    It seems we already had an FAQ question about the Vista sample rate issue. We added it maybe 4 years ago. But at the time we didn't know the root cause and so the FAQ didn't contain much detail. I'll update the SoundCheck FAQ with a link back to this forum post.

    I also went back and added a screen shot in case people can't find the setting.

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  • David (PassMark)
    replied
    What is "Sound Check"? Is that something in Windows Sound Device?
    Just for the record.
    In this context it is the Passmark SoundCheck software on this web site.

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  • Soloing1
    replied
    Thanks for the help. I rebooted and the device drivers apparently were detected and I thought they already had been? Not sure. But all is fixed. http://www.sevenforums.com/sound-audio/136644-incorrect-sample-rate-playback.html#post1174624

    Leave a comment:


  • Soloing1
    replied
    Thanks. I will look into this and post to another forum you suggest and let you know if there is any reply.

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  • sullivang
    replied
    Soloing1,
    It COULD be related to the issue I'm discussing, and if it is, it's obviously a more dramatic example. There are two issues that I have raised:

    1) Windows 7 will not change the sample rate of the audio interface to match the sample rate of the audio content, in the same way that occurred on older versions of Windows, such as Windows XP.
    2) When the sample rates do not match, processing needs to be done to convert the sample rate of the audio to the sample rate of the audio interface. It appears that sometimes, this is not occuring with high fidelity.

    I think you should work out the simplest way to reproduce the problem, document what you do thoroughly, and then report it in a more appropriate place than this forum. If you can reproduce the problem on Windows, without having to use any 3rd party applications, then I think you should contact Alesis first. (no harm in also asking in a general Windows related forum, such as this one: http://www.sevenforums.com/sound-audio/ ) For example, if you use the Windows "Sound Recorder" program to record something, and then play it back using the Windows Media Player, and the problem occurs, that would most likely point to a fundamental problem in Windows or the Alesis driver. (note that Sound Recorder on Windows 7 can't actually play back anything - not even something it has just recorded)

    If Windows works ok, maybe the next step could be to reproduce it in Cubase, and report it on the Cubase forum: http://www.steinberg.net/forum/viewforum.php?f=8&sid=132aba8b7f77ea532fdc3a50fcc8 2f2f and/or directly to Cubase support.

    If you post publicly, would you mind giving us the links to your discussions? Thanks.

    RE: SoundCheck, it's a program to testing the capabilities of your soundcard, microphone and speakers, etc. It might help with your problem, but I think it's best to do the above first.

    Greg.

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  • Soloing1
    replied
    Incorrect Sample Rate on Playback

    I have been searching all week for an answer to a problem I am experiencing and it seems your thread may have the answer. Can you help further? Here's the issue: I have an Alesis i02 audio interface and am running Cubase LE5 and also like to use audacity, too. Regardless of the program, when I record my voice using a sample rate of 44, upon playback the pitch of the voice is slowed down. When I playback at 48 it is fine, it seems. However (again regardless of the software), it does not adjust automatically. I am running Windows 7. What is "Sound Check"? Is that something in Windows Sound Device? Anyways, any thoughts on what I can do to correct this issue? I am unclear about what I should set the sample rates to in Windows 7. Could Windows 7 be the issue?

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  • sullivang
    replied
    Also, note that I have "allow exclusve access" and "give exclusive applications priority" checked in the audio interface properties, but that's obviously not allowing SoundCheck to work properly. Maybe there's a problem there.

    It goes without saying, but I think you should consider looking into improving SoundCheck on Windows 7, even if it's something as simple as popping up a warning that the user should double check that the sample rates match.

    Greg.

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  • sullivang
    replied
    Exactly, however I didn't do anything to put my machine into "shared mode" - that's just how it is all the time I think, unless the application is written to open the device in exlusive mode, I assume. (I haven't done any audio programming on Windows at all, so all this is a bit fuzzy for me)

    If you read my very first post over on the MSDN forum, you'll see that when I force XP into some kind of "shared mode" (by running two apps simultaneously), it still performs the sample rate conversion well.

    Greg.

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  • David (PassMark)
    replied
    I see. You are talking about the "shared mode" sample rate that is used to mix content on output.

    I haven't looked into this much.

    I did some reading on it, and yes, it seems there is a general consensus that the re-sampling done in Windows isn't great. So it makes sense to avoid the re-sampling where possible by setting the rates the same.

    Here is a screen shot for anyone looking for the sound card sample rate setting.

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