16 Bit Vs. 24 Bit

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PimpDaddyDA

Well-known member
Hi all...

I'm sitting on 70 hours of footage. We had a pro sound man record everything on a DAT w/boom mics at 24 BIT, 48K. He also ran XLR cables into the DVX during the shooting.

The 24 BIT DVD's of the audio sound great, however, the recorded sound on the DVX also sounds great (not as full, but very clean)

Question:

Instead of spending a million hours syncing all 24 BIT sound up, couldn't I just use the 16 BIT recordings in the DVX and then run the completed sound track thru a mixer to bring out the fullness?
Will that mixed 16bit sound as good as the 24 bit?

OR is it really best to sync up all that 24 BIT sound?

I've just started editing, and need to make a choice.

Thanks for your imput,

Pimp Daddy D
 
People are fearful of syncing separate audio. I don't thnk it is that big a deal. A nudge here, a nudge there, and you're in business. I would use the 24 bit audio if possible.

The big advantage over greater bit depth is fidelity at low volumes. The way digital audio works, the more signal you have, the better the fidelity. Analog isn't like that at all--fidelity is constant at all volume levels. With analog you run into the noise floor, however, when things get quiet, but all of the source material is still there. With digital, extremely quiet passages, especially in 16 bit, begin to sound like a low-quality digital answering machine (choppy, aliasing, etc.). 24 bit recording gives you more dynamic range, as quieter moments stll have enough resolution to be useful.


In post, you have more room to engineer sound to your liking in 24 bit. You can bump up the quieter passsages to be more present in the final mix and even things out before converting the mix to 48k/16 bit for DVD output.

I suppose one caveat would be this: if your 16 bit sound was extremely well recorded with most of it being very hot (but without digital clipping--everything pegging at 0db max), then perhaps just using the 16 bit audio would be fine and save you the time of an extra production step. But otherwise your 24 bit mix makes more sense.
 
24 bit (recorded properly to take advantage of the extra fidelity) is gonna give you far better audio then your DVX. Are you sure the recordings are 24-bit? I know of one 24bit DAT recorder and that was a rackmount device. If he was recording with DAT it was almost definately just 16bit. If he recorded with one of the new non-linear recorders (Deva, 744t, Portadrive, etc) then it's 24bit and most likely worth the effort.

Good luck
 
Yeah, I think I'll just take the time out and sync it all up. Thanks for your advice.... yeah, his box is 24bit... the sound is really rich and clean.
More work...work...work.... but I guess that's what it's all about for a good production.
 
If he had a 24 bit recorder (Tascam DA-45 HR is the only 24 bit DAT recorder I'm aware of), you will need a 24 bit player.
In other words, if those tapes playback in any standard DAT machine, they are not 24 bit.
 
If you have a good music editing program like Wavelab or a good sequencer program like Sonar, protools or cubase..you shouldn't have any problems keeping the 24bit. You might have to nudge it a bit in your editing program but if there isn't a lot of cuts and you have a good timecode it shouldn't be a problem to keep your sound quality up. You'll have to really look close that there wasn't any clipping or dropped notes in the recording process.
 
Others may disagree with me here, but I would suggest that the quality difference in the tracks has a great deal more to do with higher quality analog electronics in the DAT vs the DVX than anything related to the bit depth of the recording, especially as it relates to a couple of tracks of voice. Bit depth is far more important as it relates to mixing. You can always convert the bit depth when it is time to mix. (You definately should mix at 24 bit, especially when you are talking about mixing lots of tracks).

Without knowing how the audio was provided to your camera on the location it is hard to know the reason for the noticable difference in quality. (I would assume that he used an external preamp then sent line level signals to your DVX and to his DAT). For one, the tracks you received on the DVD could simply be louder. I have just received my DVX100a, so I have not had a chance to do much experimenting with the audio, outside from hooking up a couple of mics to make sure it works. What I can tell you is that in most situations it is extremely difficult to hear the difference between a stereo pair of raw tracks recorded at 16bit vs 24bit.

Bottom line: I would use the tracks that sound the best to you regardless of bit depth :)
 
If you can sync it from the 24bit/48khz DAT then it would be much better than the 16bit/44khz DVX...You will know the difference by listening to them. Most likely your sound guy slated every take so you can find the takes to compare them side by side. Take note if there is any clipped out parts in the audio timeline and really listen closely for the naturalism of the original sound.
 
bart's explanation is good, but this part isn't quite right:
"Analog isn't like that at all--fidelity is constant at all volume levels."
with analog, the "resolution" (the analog version of bit depth,) is the tape speed. the more tape that contains the analog signal, the more "fidelity" at all volumes. analog tape changes frequency response at various volumes, especially evident at higher levels where the tape is getting saturated and tape compression starts to happen.
 
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