Topic: Benefits Of Converting a 16 Bit Recording To 32 Bits Before Editing

[fmaderjr]

My question for you advocates of 24 bit recording: Do you get many of the benefits of of an original 24 bit recording if you take an original 16 bit recording and convert it to 24 or 32 bits before editing (particularly if the recording was made at too low a level and needs a lot of boosting)?

The reason I ask is that I wanted to test my Church-Audio cards so I used them to record some friends' cover "band" (actually 2 grand pianos & vocals) as a 2nd rig directly into a MicroTrack I (in 16 bit mode). My main rig was a set of DPA 4060's →ST-9100 → iHP-120. Somehow I got the MicroTrack levels so low that I needed to boost the levels in post about 30 DB while the iHP recording only needed to be boosted about 6 DB.

I did the boosting in Adobe Audition after converting the 16 bit original files to 32 bit. Then after editing, I converted back to 16 bit. I was stunned how good the MicroTrack-Church card recording sounded even after a 30 DB boost. Practically indistinguishable from the main rig recording in that particular setting. So at least to my ears, it appears that you must get at least some of the benifits by doing your editing in the higher bit rate.

[John Kary]

Someone correct me if I'm wrong, but most DAW's process mixing at a high internal bit-rate regardless of what your project or files are when you bring them into the app.  You said you used Audition, but didn't say if you independently processed the files by themselves, or if you used multi-track mode.

At least with the newest Audition 3 (not sure about older versions but I bet this applies also), you can set what bit-rate to process multi-track mixing/mixdown at up to 32-bit.  Select Edit > Preferences (or hit F4) and go to the the Multitrack tab.

Keep in mind that if you are manually upconverting your files to 32-bit, working with them at 32-bit then exporting, you will need to dither when converting the audio back to 24 or 16-bit.

Specifically addressing your question, I'm fairly sure I remember Bob Katz saying somewhere that you shouldn't need to upconvert your files, as the DAW processes everything at a high internal bitrate anyway.  Unfortunately, you may be at the mercy of the DAW's internal dither when coming down from 32-bit back to 24 or 16-bit.  I would recommend rendering your file at at least 24-bit after editing, and then running it through the best dither you have available.

In Auditon's case, if you have a VST dither you want to use (like iZotope Ozone's excellent MBIT+ dither), slap it on as the last VST effect on the master bus and export to your target bitrate.

[Brian Skalinder]

Someone correct me if I'm wrong, but most DAW's process mixing at a high internal bit-rate regardless of what your project or files are when you bring them into the app.

FWIW, that's my experience with Audition v1.5, Wavelab v5, Audacity (various versions) and SAM SE v8.3 for both mixing and editing (since some apps treat these operations differently).  Some allow user-selectable internal processing and/or mixing bit-depth, others default to 24-bit or 32bfp with no option to change, and some require proper configuration before using the app (for example, Audition used to default to opening 16-bit files, editing at 32bfp, and auto-dithering back to 16-bit after each edit operation...so if you perform more than a single edit on any portion of the waveform, you're dithering multiple times).

Kinda goes without saying, but...always best to make sure your s/w is configured properly for what you're trying to accomplish. 

[fmaderjr]

Thanks for your input guys. +T to you both. FWIW I was just using Audition 3.0's Editing mode with the option selected to auto-convert all files to 32 bit upon opening. I never use and don't yet understand Multi-Track mode. At the moment I don't really care to anyway. Editing mode seems to be working well for my live recordings. By reading the posts as taperssection I've gotten pretty good in practice at making live recordings, but am very weak on my knowledge of the technical side.

I don't have a VST dithering program and am weak on my knowledge of dither settings. I was using Audition settings of:
Dither Depth:    0.45
p.d.f.:             Triangular
noise shaping:  (44.1 KHz)

As I said, the result sounds great to my ears, even with 30 DB of boost, but I don't know if I could have done better with other settings.

[John Kary]

It's a lot to absorb at once if you try to, but keep doing what sounds good to you and try to pick up more as you go.

An amazing repository of articles is housed by renown mastering engineer Bob Katz at his website http://www.digido.com/ .  Some of it might go over your head at first, but the more you read into it the more it will make sense.

[fmaderjr]

Looks like a great site. Thanks!