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#1
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Sound driver question
A puzzling audio problem on one of my laptops: I noticed the windows sound
events all sounded lower in pitch than normal (guessing about 3% or 4% lower) on this Dell e6500 laptop. So I copied some of the sound events over to a temp folder, and played them using various wav players, and sure enough, they all sound lower in pitch (with the exception of one wav player, which renders the pitch correctly). I think I have finally noticed one thing unique about this: these windows event sounds are mostly 22.05 kHz, 16 bit wave files, not the standard 44.1 kHz. Sitll, they should all play with the correct pitch! I've got the up-to-date IDT audio driver, so that's apparently not the issue. This Dell e6500 uses a IDT High Definition Audio Codec (whether I like it or not). I was hoping to find some other alternative audio codec that might work better (assuming that codec is related to this problem), but I haven't found any alternative (on the Dell drivers site, and they are all listed there). How this can happen is puzzling to me, however, and short of getting some alternative audio driver(s), I don't see an obvious solution, unless I'm missing something. It's not the end of the world, but I'd sure like to know if I can rectify it, or if someone has some suggestions. As I said, everything is hunky dory in Device Manager and all drivers are up to date. What is also interesting is that one really simple player (called Billy Player) plays the pitch correctly, but the others do not. Maybe it means there is some overhead in decoding non 44.1 kHz audio files on this system, causing some latency? But that just seems too far out to me. Besides which, Billy Player says it's using the IDT audio and it plays it correctly. Any ideas? TIA. |
#2
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Sound driver question
Bill in Co wrote:
A puzzling audio problem on one of my laptops: I noticed the windows sound events all sounded lower in pitch than normal (guessing about 3% or 4% lower) on this Dell e6500 laptop. So I copied some of the sound events over to a temp folder, and played them using various wav players, and sure enough, they all sound lower in pitch (with the exception of one wav player, which renders the pitch correctly). I think I have finally noticed one thing unique about this: these windows event sounds are mostly 22.05 kHz, 16 bit wave files, not the standard 44.1 kHz. Sitll, they should all play with the correct pitch! I've got the up-to-date IDT audio driver, so that's apparently not the issue. This Dell e6500 uses a IDT High Definition Audio Codec (whether I like it or not). I was hoping to find some other alternative audio codec that might work better (assuming that codec is related to this problem), but I haven't found any alternative (on the Dell drivers site, and they are all listed there). How this can happen is puzzling to me, however, and short of getting some alternative audio driver(s), I don't see an obvious solution, unless I'm missing something. It's not the end of the world, but I'd sure like to know if I can rectify it, or if someone has some suggestions. As I said, everything is hunky dory in Device Manager and all drivers are up to date. What is also interesting is that one really simple player (called Billy Player) plays the pitch correctly, but the others do not. Maybe it means there is some overhead in decoding non 44.1 kHz audio files on this system, causing some latency? But that just seems too far out to me. Besides which, Billy Player says it's using the IDT audio and it plays it correctly. Any ideas? TIA. In Audacity, record a reference sine wave tone in a waveform. Say, 440Hz. Play it back. Pass the signal to a second computer for recording. See if the ratio is 44100/48000 , implying some driver is using the wrong sampling rate for something. Audacity has an FFT display, which can show the frequency of spikes in the frequency domain graph. As far as I know, sound is managed by "keeping a buffer full". That means, to play a sample, the hardware is set to a nominal rate. If the buffer drops below a threshold value (like, "half full"), an interrupt is issued, and the sound subsystem loads a bit more stuff into the buffer. The processor itself isn't really metering the flow. You would think the sound subsystem could underflow, be data starved, and have to repeat samples (create a flat spot in the waveform at some point), but I suppose it's a function of the source. For playback of music, it just means the entire composition finishes sooner. For video playback, with a video and audio sound stream, there's likely to be some other sort of pacing method. If it was a crystal timebase reference problem, that's probably good to 100ppm. And I don't know if human pitch sensing can detect that small of a shift. https://en.wikipedia.org/wiki/Pitch_(music) "Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents)." Which suggests you cannot hear 100ppm of error. But 48000/44100 or about 9% error caused by a sampling rate setting error in a driver, you could hear that. A number of sound chips are inherently 48000 sampling rate, and some other rates are done by resampling or something. In any case, the purpose of recording the output of the defective setup, is to note whether the error is "exactly 9%", if you get my drift... In other words, it's a known issue with the sampling or resampling going on in some chips and their drivers. If the error was some other weird ratio (suggestive of a broken quartz time base), then you'd have to come up with a new theory to explain it. On your "measurement machine", the chip may offer a 192KHz sampling rate. But this doesn't mean it can properly reproduce a 96KHz sine wave (Nyquist). The input filter (let's pretend it's an RC low pass filter) is set for around 50KHz or so. Frequencies higher than that can be severely attenuated. But, using the 192KHz sampling rate doesn't hurt the time domain measurement capability. By using the high sampling rate, you may improve the pitch measurement accuracy. That's assuming the chip on the second computer isn't doing something stupid too :-) Here's an example of me checking Audacity 440Hz on the other machine, by using Audacity on this computer to record LineIn. On the source Audacity, the "Generate" menu produces a 30 second 440Hz tone by default. And I've recorded that on this computer, then done an FFT on it. https://s15.postimg.cc/5brhkzb63/Lin...other_comp.gif Paul |
#3
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Sound driver question
In message , Paul
writes: Bill in Co wrote: A puzzling audio problem on one of my laptops: I noticed the windows sound events all sounded lower in pitch than normal (guessing about 3% or 4% lower) If that _is_ the difference, you have good ears: adjacent semitones (on an even-tempered scale, which is what's mostly used nowadays) differ by 2^(1/2), which is about 6%, so you're noticing well under that. I think I would certainly notice that in successive playings, but for a sound that I only hear for certain events, I don't think I would. (Out of curiosity, which sounds did you notice this on? What sound scheme are you using, or is it one you've created yourself?) on this Dell e6500 laptop. So I copied some of the sound events over to a temp folder, and played them using various wav players, and sure enough, they all sound lower in pitch (with the exception of one wav player, which renders the pitch correctly). I think I have finally noticed one thing unique about this: these windows event sounds are mostly 22.05 kHz, 16 bit wave files, not the standard 44.1 kHz. Sitll, they should all play with the correct pitch! My first thought _was_ a faulty reference crystal, but if it's only sounds at a certain rate (and only some - even if all but one - players), then it's not going to be that. You say you "noticed" it. Do you mean/think it has _started_ doing it, or has always done it on that machine? (Did you notice it because you happened to have the same event - and sound - on two machines at around the same time? There, I too would have noticed half a semitone difference, I think. [Depending on what the sound was.]) I'd be tempted to load them into something that can do it (Audacity?, GoldWave), and upsample them to 44100, and see if they then play correctly - and, try downsampling some 44100 files to 22050, and see if they then play oddly. (I'm just wondering if there's some other property that's particular to the sound event files provided by Microsoft. If you temporarily associate a 44100 Hz .wav file to one of your events, does it play right?) Though you say it's players too, so not just the Events subsystem. [] See if the ratio is 44100/48000 , implying some driver is using the wrong sampling rate for something. Audacity has an FFT display, which can show the frequency of spikes in the frequency domain graph. That'd be nearly 9%, or 1½ semitones. (Though Bill did say he _guessed_ at the 3 or 4 %.) Good thinking though. [] If it was a crystal timebase reference problem, that's probably good to 100ppm. And I don't know if human pitch sensing can detect that small of a shift. I think the cheapest might be as much as 500 ppm. But that's basic accuracy, or drift over time (months or years, or with _considerable_ change in temperature). And even that's 0.05%. But - unless the sound system uses different crystals for different rates, and I can't see it doing that (certainly not for 22050 and 44100 as they're related) - and Bill says it's only some playings that are low/slow, I don't think it's that. (Writing "low/slow" there made me think: it'd be interesting to see if it is only pitch, or duration that's affected - but you'd need a longish [say well over a minute] file, and one with a clearly audible start and stop [maybe your burst of concert A], to check that. But I suspect duration _would_ be affected.) https://en.wikipedia.org/wiki/Pitch_(music) "Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents)." Which suggests you cannot hear 100ppm of error. Interesting that it _isn't_ a percentage for low notes (assuming the above is correct). [] -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf "I'm a paranoid agnostic. I doubt the existence of God, but I'm sure there is some force, somewhere, working against me." - Marc Maron |
#4
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Sound driver question
J. P. Gilliver (John) wrote:
In message , Paul writes: Bill in Co wrote: A puzzling audio problem on one of my laptops: I noticed the windows sound events all sounded lower in pitch than normal (guessing about 3% or 4% lower) If that _is_ the difference, you have good ears: adjacent semitones (on an even-tempered scale, which is what's mostly used nowadays) differ by 2^(1/2), which is about 6%, so you're noticing well under that. I think I would certainly notice that in successive playings, but for a sound that I only hear for certain events, I don't think I would. (Out of curiosity, which sounds did you notice this on? What sound scheme are you using, or is it one you've created yourself?) on this Dell e6500 laptop. So I copied some of the sound events over to a temp folder, and played them using various wav players, and sure enough, they all sound lower in pitch (with the exception of one wav player, which renders the pitch correctly). I think I have finally noticed one thing unique about this: these windows event sounds are mostly 22.05 kHz, 16 bit wave files, not the standard 44.1 kHz. Sitll, they should all play with the correct pitch! My first thought _was_ a faulty reference crystal, but if it's only sounds at a certain rate (and only some - even if all but one - players), then it's not going to be that. You say you "noticed" it. Do you mean/think it has _started_ doing it, or has always done it on that machine? (Did you notice it because you happened to have the same event - and sound - on two machines at around the same time? There, I too would have noticed half a semitone difference, I think. [Depending on what the sound was.]) I'd be tempted to load them into something that can do it (Audacity?, GoldWave), and upsample them to 44100, and see if they then play correctly - and, try downsampling some 44100 files to 22050, and see if they then play oddly. (I'm just wondering if there's some other property that's particular to the sound event files provided by Microsoft. If you temporarily associate a 44100 Hz .wav file to one of your events, does it play right?) Though you say it's players too, so not just the Events subsystem. [] See if the ratio is 44100/48000 , implying some driver is using the wrong sampling rate for something. Audacity has an FFT display, which can show the frequency of spikes in the frequency domain graph. That'd be nearly 9%, or 1½ semitones. (Though Bill did say he _guessed_ at the 3 or 4 %.) Good thinking though. [] If it was a crystal timebase reference problem, that's probably good to 100ppm. And I don't know if human pitch sensing can detect that small of a shift. I think the cheapest might be as much as 500 ppm. But that's basic accuracy, or drift over time (months or years, or with _considerable_ change in temperature). And even that's 0.05%. But - unless the sound system uses different crystals for different rates, and I can't see it doing that (certainly not for 22050 and 44100 as they're related) - and Bill says it's only some playings that are low/slow, I don't think it's that. (Writing "low/slow" there made me think: it'd be interesting to see if it is only pitch, or duration that's affected - but you'd need a longish [say well over a minute] file, and one with a clearly audible start and stop [maybe your burst of concert A], to check that. But I suspect duration _would_ be affected.) https://en.wikipedia.org/wiki/Pitch_(music) "Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents)." Which suggests you cannot hear 100ppm of error. Interesting that it _isn't_ a percentage for low notes (assuming the above is correct). [] I did some more experiments. The pitch shift is around 40 cents, or a bit over 2 %. I can definitely tell if a song is off pitch by 2 %. (In fact, on the radio, if it's off that much, it's annoying to me (and I can tell that from my own memory of the original song, even from years ago). It happens on all of the windows sound events, since they are all 22.05 kHz wave files. And yes, it has always been this way on this one laptop. So just for kicks, I converted one of them to 44.1 kHz, and sure enough, it sounds fine; reconvert it back, and got the same problem. And again, this issue happens on all my media players (with the exception of that one simple one called Billy Player, which apparently must process the 22K audio signal differently - and correctly). (And it is nowhere near a 9 % pitch error, so that other idea isn't explaining it, either). Maybe it has something to do with the buffering as Paul suggested, but I don't know (some of these sound events are only one second) |
#5
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Sound driver question
In message , Bill in Co
writes: [] I did some more experiments. The pitch shift is around 40 cents, or a bit over 2 %. I can definitely tell if a song is off pitch by 2 %. (In fact, on the radio, if it's off that much, it's annoying to me (and I can tell that from my own memory of the original song, even from years ago). It Hmm, a third of a semitone, nice. happens on all of the windows sound events, since they are all 22.05 kHz wave files. And yes, it has always been this way on this one laptop. So just for kicks, I converted one of them to 44.1 kHz, and sure enough, it sounds fine; reconvert it back, and got the same problem. And again, this issue happens on all my media players (with the exception of that one simple one called Billy Player, which apparently must process the 22K audio signal differently - and correctly). (And it is nowhere near a 9 % pitch error, so that other idea isn't explaining it, either). Maybe it has something to do with the buffering as Paul suggested, but I don't know (some of these sound events are only one second) So the fault only occurs with one set of hardware (that one laptop), and at only one sample rate (have you tried 11.025 kHz? Or something that _isn't_ a binary multiple/factor thereof, such as 24 kHz?), unless played with one particular player. I'm out of ideas (-:! I think seeing if the _duration_ is affected might be useful to know, although I'm not sure why. (You'd need a long enough file to be able to time it, though, which for a 2% error, probably means a couple of minutes or so at least. With a clearly-discernible start and end so you know when to click the stopwatch or whatever.) -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf Everyone learns from science. It all depends how you use the knowledge. - "Gil Grissom" (CSI). |
#6
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Sound driver question
Bill in Co wrote:
J. P. Gilliver (John) wrote: In message , Paul writes: Bill in Co wrote: A puzzling audio problem on one of my laptops: I noticed the windows sound events all sounded lower in pitch than normal (guessing about 3% or 4% lower) If that _is_ the difference, you have good ears: adjacent semitones (on an even-tempered scale, which is what's mostly used nowadays) differ by 2^(1/2), which is about 6%, so you're noticing well under that. I think I would certainly notice that in successive playings, but for a sound that I only hear for certain events, I don't think I would. (Out of curiosity, which sounds did you notice this on? What sound scheme are you using, or is it one you've created yourself?) on this Dell e6500 laptop. So I copied some of the sound events over to a temp folder, and played them using various wav players, and sure enough, they all sound lower in pitch (with the exception of one wav player, which renders the pitch correctly). I think I have finally noticed one thing unique about this: these windows event sounds are mostly 22.05 kHz, 16 bit wave files, not the standard 44.1 kHz. Sitll, they should all play with the correct pitch! My first thought _was_ a faulty reference crystal, but if it's only sounds at a certain rate (and only some - even if all but one - players), then it's not going to be that. You say you "noticed" it. Do you mean/think it has _started_ doing it, or has always done it on that machine? (Did you notice it because you happened to have the same event - and sound - on two machines at around the same time? There, I too would have noticed half a semitone difference, I think. [Depending on what the sound was.]) I'd be tempted to load them into something that can do it (Audacity?, GoldWave), and upsample them to 44100, and see if they then play correctly - and, try downsampling some 44100 files to 22050, and see if they then play oddly. (I'm just wondering if there's some other property that's particular to the sound event files provided by Microsoft. If you temporarily associate a 44100 Hz .wav file to one of your events, does it play right?) Though you say it's players too, so not just the Events subsystem. [] See if the ratio is 44100/48000 , implying some driver is using the wrong sampling rate for something. Audacity has an FFT display, which can show the frequency of spikes in the frequency domain graph. That'd be nearly 9%, or 1½ semitones. (Though Bill did say he _guessed_ at the 3 or 4 %.) Good thinking though. [] If it was a crystal timebase reference problem, that's probably good to 100ppm. And I don't know if human pitch sensing can detect that small of a shift. I think the cheapest might be as much as 500 ppm. But that's basic accuracy, or drift over time (months or years, or with _considerable_ change in temperature). And even that's 0.05%. But - unless the sound system uses different crystals for different rates, and I can't see it doing that (certainly not for 22050 and 44100 as they're related) - and Bill says it's only some playings that are low/slow, I don't think it's that. (Writing "low/slow" there made me think: it'd be interesting to see if it is only pitch, or duration that's affected - but you'd need a longish [say well over a minute] file, and one with a clearly audible start and stop [maybe your burst of concert A], to check that. But I suspect duration _would_ be affected.) https://en.wikipedia.org/wiki/Pitch_(music) "Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents)." Which suggests you cannot hear 100ppm of error. Interesting that it _isn't_ a percentage for low notes (assuming the above is correct). [] I did some more experiments. The pitch shift is around 40 cents, or a bit over 2 %. I can definitely tell if a song is off pitch by 2 %. (In fact, on the radio, if it's off that much, it's annoying to me (and I can tell that from my own memory of the original song, even from years ago). It happens on all of the windows sound events, since they are all 22.05 kHz wave files. And yes, it has always been this way on this one laptop. So just for kicks, I converted one of them to 44.1 kHz, and sure enough, it sounds fine; reconvert it back, and got the same problem. And again, this issue happens on all my media players (with the exception of that one simple one called Billy Player, which apparently must process the 22K audio signal differently - and correctly). (And it is nowhere near a 9 % pitch error, so that other idea isn't explaining it, either). Maybe it has something to do with the buffering as Paul suggested, but I don't know (some of these sound events are only one second) 22050 * 1.02 or 22050 / 1.02 , doesn't give a "canonical" frequency. I can't guess as to where that is coming from. IDT bought Sigmatel, which means the part number and logo of some of them, indicates Sigmatel. And Googling on the Sigmatel part number might bring up more hits for you. I don't have a strong feeling that IDT was serious about being a sound chip maker. When you look at your FFT plot, is the spike nice and sharp, or is the tip of the spike spread out a bit ? That would be a check that "something has broken loose" in the playback hardware. Like an unlocked clock synthesizer. You're going to need to dig up a part number for that thing, to find further possibilities. Paul |
#7
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Sound driver question
In message , Paul
writes: [] When you look at your FFT plot, is the spike nice and sharp, or is the tip of the spike spread out a bit ? That would be a check that "something has broken loose" in the playback hardware. Like an unlocked clock synthesizer. Except if it's that, why does the one player among the several he's tried (I think he said it was called "Billy"; I've never heard of it) _not_ exhibit the fault (despite using, presumably, the same hardware)! It's an odd one. You're going to need to dig up a part number for that thing, to find further possibilities. Paul (He'd probably have to open up the laptop to find that, which is usually a tedious process. Unless you can point him at a utility that will analyse/interrogate peripheral chips electronically.) -- J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf The desire to remain private and/or anonymous used to be a core British value, but in recent times it has been treated with suspicion - an unfortunate by- product of the widespread desire for fame. - Chris Middleton, Computing 6 September 2011 |
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