16 bit? 24 bit?

Posted: Sun Nov 06, 2005 7:51 pm

when is it best to record in which bit depth? i understand that the bit depth is is relative to loudness in dB's (each bit = 3 dB i think?), but still don't quite grasp when to record in which. i'd assum 24 bit, then dither down to 16 bit to go to cd in the mastering process, but i am not sure if this is correct. any help, links, suggestions would be great! thanks

Posted: Sun Nov 06, 2005 8:04 pm

I think it is fine to record all things at 24bit
then convert later as needed.

If you are pressed for drive space for some reason then 16 bit could help.

If all material is going to be injested direct to a 16 bit system and you don't want to waist time with a conversion then again ... 16 bit.

very generally
music at 44.1k/24bit convert to 16 bit for CDaudio
and video stuff at 48k/24bit unless the video editor only works with 16bit files.

Posted: Sun Nov 06, 2005 8:40 pm

It's 6 dB ber bit, and this refers to dynamic range.

16 bit audio has a dynamic range of roughly 96 dB, where as 24 bit has a dynamic range of roughly 144 dB, which exceeds the dynamnic range of our ears and most of our playback equipment. Most people will listen at 80 dB or so with 50 dB of background noise, so the most you're gonna get out of that situation is about 40 dB (no, I didnt subtract wrong... you can still hear signal in the presence of noise). Where it really matters is in sensitive music heard in sensitive environments. On the other hand, if your system can easily handle it, why not?

Posted: Sun Nov 06, 2005 9:02 pm

thanks for the replies.. exactly what i needed to know! makes perfect sense. thanks guys.

Posted: Mon Nov 07, 2005 4:56 am

Hello,

A little precision.
Kev infos are correct.
David french's infos also but would need some precisions.

It's true a finished piece of recording will likely be listened to in a 40 dB maximum dynamic range. (and most of the time, much less, depending on the kind of music/audio it is).
But that is not strictly related on how you record the sound.
Most of the time, sound sources in real world do have a big dynamic range, exeeding 40 dB (an orchestra for instance). So when recording you'll have to adapt this big dynamic range to your available recording dynamic possibility. When recording in 16 bits, a 96 dB dynamic range is true theorically, but false in reality. Digital recording, contrary to analog, does add a lot of distortion at low level (hence the need for dither for instance).
Oversimplifically, a signal recorded at -40FS (a pianissimo) will be coded on (40/6=6; 16-6=10) 10 bits. Not a lot and the quieter the sound, less bits to record it, and more distortion on it.

So 24 bits helps to record low sounds with less distortion, so enable you to work differently for recording. So you will have a "cleaner" sound to work with when you'll need to cranck up the low parts when mixing. It's a slightly different way of working, which is of course suited to sound source with a wide and unpredictable dynamic range.

Hope it helps,

Laurent.

Posted: Mon Nov 07, 2005 12:18 pm

thanks laurent!

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