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when mixing(bouncing) a 16-bit mix internally (Pro ToolsIII), is it necessary, or at least important, to have a dither plugin on the master fader? ie. Waves L1 set to dither to 16-bit? i've heard various things about truncation, mixer channel summing, etc. (yes, i realize this may yet be another case of DUC-induced-paranoia!)

Comments

Greg Malcangi Tue, 07/03/2001 - 01:10

Hi Felix,

I think your question should really have been posted in the Pro Tools Forum over in the DAWworld section. Providing Harvey doesn't mind I'll answer you here though:

I'm not totally clear about your question. Are you tracking, mixing and mastering (bouncing) all at 16bit? If so there may not be much to be gained by dithering your master fader. Dithering is essentially used to hide quantization errors (QEs) which are caused by the music requiring smaller steps in volume than your bit resolution can provide. The most common cause of QEs is truncation, usually when making a 16bit master from say 24bit tracking and mixing material. The second most common cause of QEs is in material with a wide dynamic range, particularly in very quiet sections or with fades to infinity; reverb tails, etc. If your material is of this style you may experience audible QEs especially if you only have 16bit resolution during tracking/mixing.

My advice is to crank up the monitoring volume of your whole mix during any quiet passages or fade outs and listen for any problems. If you find QEs that you think are causing a problem then add dither to your master faders, if the problem is just coming from a single channel place your dither plug on that channel. Don't go through all your channels solo'ing them and checking for QEs though, just listen to the whole mix. The reason for this is that if you have a single channel that has some QEs the chances are that these QEs will be masked if you also have other channels in the mix at the same time.

BTW, forget about mixer channel summing though, this is definitely DUCIP (DUC-induced-paranoia!).

I'm not sure how clear my explanation is. If you have any further questions don't hesitate to ask.

Greg

anonymous Tue, 07/03/2001 - 06:11

cool! thanks for clearing that up! i am completely in 16bit realm, btw. so, as i understand, quantization errors are not going to effect the sound quality unless possibly during quiet passages or fade-outs were they could possibly be heard under the right(or worng) circumstances. sorry for carrying this over here from duc, but i just wasn't getting the explaination i was looking for... there oughta be a forum called DUCIP, for clearing up all the nit-picky daw gossip that gets sparked up over there. i mean its always important to look for and confirm ways to improved our mix-downs, but sheeze!

:roll:

Bob Olhsson Tue, 07/03/2001 - 06:50

The only time you don't need to dither is when you are doing NO signal processing whatsoever. Even a .1dB gain change creates a 48 to 64 bit word that has to be dithered back down to 16 bit to avoid distortion that can never be removed or covered up after the fact.

Not dithering is like not using bias on an analog tape recorder. Different kinds and amounts of dither just like different kinds and amounts of tape bias can make significant differences. Sometimes you might not want to use dither or bias as an effect but that choice always generates unnecessary distortion.

anonymous Tue, 07/03/2001 - 09:33

very cool. so now its been clarified yet further... i should put a dither plug on the master fader then?