Apply Dither When BTD From 16-Bit Session To 16-Bit Output?

[Alan Brownstein]

I've searched around the forums but did not see a previous post on this question. I'm well aware of the need to apply dither when converting from 24-bit to 16-bit (due to the truncation of bits that occurs). But what is the common wisdom on using dither when bouncing to disk from a 16-bit session to a 16-bit output file? I have heard/read that dither is ideal even in this case, due to the internal processing which is taking placing at a higher bit-depth (i.e. the 48-bit internal mixer). Is it overkill to apply dither in this case, or is it necessary?

Alan

[albee1952]

My 2 cents says it is not needed but you could always do 2 bounces and use dither on one of them and listen back and let us know if you hear any difference or improvement either way.

[Top Jimmy]

The 48-bit fixed point mixer is only in PT-HD. LE has a 32-bit floating point mixer. Having the dither plugin as the last in the chain on the master fader of your bounce bus/output is a good idea since you're dropping from 32 bits to 16. You may be mixing 16 bit sources, but the math in adding them up will result in a word greater than 16 bits. The only problem is that whatever 16-bit quantization noise you have in the source tracks can be audible in the noise floor of the mix. This is why recording at 24 bit is preferable. Quantization noise is more objectionable than ordinary white noise.

[Roey]

Yeah,

As long as any mixing or processing takes place, you should dither, whether it is to a 16 bit file or 24 bit file - marks no difference.

There has been a bug in versions prior to 7.3.1cs4 where dither was applied whether or not you want it.

Thanks,

[Alan Brownstein]

Thanks for the replies. That's pretty much what I thought -- use 16-bit dither pretty much any time you are bouncing to 16-bit final output from a 16-bit session, so long as the audio being bounced is being mixed OR processed in some way (whether by plug-in, volume automation, etc). For example, if performing a BTD on a single stereo 16-bit track with plug-in processing applied (but not being mixed with other audio), you would still use dither if the output of that BTD was intended for final distribution (on a CD, for example), because bit truncation is occuring after it passes through the 32-bit internal mixer. Do I have that correct?

Also, in this case, it would obviously be correct to turn off the dither feature within Waveburner, or Jam, so that a second pass of dither wasn't being applied? Come to think of it, does anyone know what set of rules Jam and/or Waveburner use for applying dither? Do they apply it across the board (i.e. to all files in the track list)? Or only to 24-bit files, or to tracks that they themselves are processing in some way (i.e. tracks which are being crossfaded)?

-Alan