Old 04-13-2017, 05:15 PM   #1
Comprador
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Default Recording bit depth dropping from 24 to 2

Hello,

Last weekend I recorded drum tracks in Reaper for nineteen songs. I've been looking through the project files this week. Several drum takes in two of the nineteen project files sounded notably worse. I thought one of the preamps was on the fritz, but eventually when I looked at the .wav file info for the recordings on these takes, the bit depth had dropped from the default "Bits/sample: 24 (int)" to "2 aDPCM." I opened all of the project files in the same way, used the same interface, laptop, etc. The takes on which the bit depth dropped by a factor of 12 weren't at the beginning nor the end of the sessions, and there are prior takes in the same project files where the .wav files saved at 24 bits/sample, so I have no clue why the bit depth would have changed and then evidently changed back. Has anyone experienced something similar to this before? Any idea why it happened and how I may prevent it from happening again?

What's also strange is I would expect 2 bits to sound much worse than 24 bits than the corrupted (or whatever) takes do. The cymbals sound sizzlier and more 'digital' / 'pixelated' (sorry for my imprecise diction) but it's more comparable to the difference between a 44.1 kHz sample rate and a 32 kHz. But every project and the interface had the sample rate set to 48 kHz. The bit depth is the only thing that changed.

I disabled wifi access on the recording laptop, but I can transfer and post some screencaps or recordings if that would be helpful to anyone.
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Old 04-13-2017, 11:27 PM   #2
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I had this happen to me the other day, have no idea why.
I just thought I may have accidentally clicked on it and just didn't notice, but now that you brought it up, I'm beginning to wonder.
Weird coincidence we made the exact same mistake ? Or weird bug ?
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Old 04-14-2017, 03:35 AM   #3
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Any MIDI files around? Those are 2-bit
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Old 04-14-2017, 03:57 PM   #4
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There must be some file header corruption or some such. If they were truly 2 bit recordings, you wouldn't have "sizzlier and more 'digital' / 'pixelated'" sound. You'd have full on noise and at a very low level.

I'd check up on your hard drive. There might be other corruption in other files. Got to be a scenario where altering one of the bits in the header gets you that erroneous 2 bit reading.

Or it could be something like your system struggling and you are having data truncated when the CPU gets too busy. Then said truncation happened in the middle of the file header being written for those cases.

That's what I'd look for.
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Old 04-14-2017, 04:27 PM   #5
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Quote:
Originally Posted by cyrano View Post
Any MIDI files around? Those are 2-bit
I downloaded a reaper project to try and check/ confirm a bug and it did have MIDI "stuff".
That must have changed the setting on me...
all I know about MiDI is I think you're supposed to use all caps when spelling it...
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Old 04-15-2017, 08:33 AM   #6
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Quote:
Originally Posted by serr View Post
If they were truly 2 bit recordings, you wouldn't have "sizzlier and more 'digital' / 'pixelated'" sound. You'd have full on noise and at a very low level.
Not with the 2 bit cADPCM format. The sound resulting from that is actually surprisingly tolerable. But of course there's no reason at all ever to use that for recording...
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Old 04-15-2017, 08:54 AM   #7
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Quote:
Originally Posted by Xenakios View Post
Not with the 2 bit cADPCM format. The sound resulting from that is actually surprisingly tolerable. But of course there's no reason at all ever to use that for recording...
So this isn't actually looking at the PCM audio data and seeing only 2 bits used. This is a "2 bit format" as named but is actually not literally 2 bit PCM data.
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