24 to 16 Bit Dithering for Final Masters

[DaveI]

This is a question - or a series of questions.

I use Waves LinMB and L2 for final mastering and CD creation. Typically, I bounce 24 bit waves with no 2 mix processing out of Pro Tools. I then use Sony's CD Architect with the Waves plugins on it's master fader doing the final processing and dithering. I assume that the CD is then cut with the L2's 24 to 16 bit dithering algorithms (Sony provides a dithering plug but I don't use it). OK, the problem that brought the question - CD Architect is great for adjusting final volumes, etc. but it crashs too frequenty to be usable when using the Waves plugins on individual CD tracks (probably gets confused about delay compensation with the heavier plugs). Individual track processing is necessary to really get the final mastering adjustments right for each song (instead of just having the plugs on the master fader).

I'm thinking of doing the LinMB and L2 processing out of Pro Tools for each mix, then importing the waves into CD Architect for sequencing, time between songs, etc. but not dithering and volume changes. So the question - if I place the LinMB and L2 at the end of the PT master fader plugin chain and use the 16 bit ditering that it provides, will that be what is bounced out (if I select a 16 bit output for the bounce)? Or is PT doing something more/different?

Maybe a better way to ask the question, is "What should the output processing steps and chain be for these plugs to get to the best audio quality for the CD?"

[albee1952]

Rather than analyze your technique, I'll just give you mine. I bounce to disk at 24 bit with no master fader. I import the 24 bit stereo interleaved file into either WaveLab or my PT mastering session. Then I add Waves L2, always in the last insert slot(don't let it hit harder than 2-3db of reduction) and select 16 bit on the L2 dither section. This is also when I trim the head/tail and add a fadeout if needed. If I'm in PT, I bounce to 16 bit/ 44.1K, stereo interleaved. If I'm in WaveLab, I render the whole file in place and save it. Either way, the new final gets saved to a folder for CD-ready files (i.e. 16 bit/44.1K/stereo interleaved). I use Wavelab to burn my CD's but that step is just burning, no other mastering or anything is done at that stage. If I need to adjust the blank time between songs(other than the global setting) I just add silence to the end of a track. Maybe your trouble is trying to do mastering and CD burning in one pass? I also suggest making mp3 versions (if you want them) before you use L2 as sometimes the L2 seems to make mp3 versions sound a bit crunchy. Whatever mastering plugs you use, make sure the L2/dither is last in line.

[records]

Dither would be the very last thing to do because you may find problems after you sequence your tracks in the CD program, and you may have to go back, fix things, and apply a dither again. I also don't know if you'll find a right dither without hearing other tracks on the album. (why just L2? You also have Pow-r dither if you use PT6.) I haven't asked my mastering engineer how he does, but I assume he applies a dither at the very end of mastering stage (audio part of mastering stage, I mean)

[albee1952]

Yes, dither is the absolute last process. I usually use L2 anyway so using the dither that L2 includes is just a matter of convenience. I haven't really taken the time to get analytical in comparing all the dither options. Several months ago I ran the same bounce thru 5 different dithers (L2 w/3 noise shaping settings, Pow-r dither and the stock Digi dither and I was hard-pressed to hear a difference. Maybe I need better D/A before I will notice if one is better sounding than the others.

[liberccxx]

another (and much simpler option) is to give an all-in-one mastering plug a try. route all input tracks to a aux submix, then to a final audio track. there are several out there. izotope ozone provides a fully functional 30-day demo and has all the major mastering tools in one plug. maybe not the quality of the previously mentioned methods but much easier and quicker and the sound quality (for ozone anyway) is surprising. it is a bit of cpu hog but if your final mix is at or below +/- 40% of cpu it will be fine. free (to try) and lots of fun to tweak as every feature has solo/bypass. i have compared it to other methods and it is hard to tell the difference once you've got it down.