Topic: 32bit in Reaper question

[Twenty8]

I use a MixPre 6ii.  I record 32bit float/48kHz.  I bring the polywav file into Reaper.  I explode the polywav to multi-track... and away we go on processing.

My question is:
Do I need to apply dither to my renders?  I am rendering to 24bit/48kHz wav to later make flac in TLH.  Do I just need to apply dither if I make an additional 16bit/44.1kHz copy?

[jadedphan]

i always dither, rather than just let the software save or convert while saving ....

[Twenty8]

I don't think I ever noticed that after I explode the polywav in Reaper, the tracks are still 32 bit.  How I did not know this was native behavior is an oversight, even after 6 months of taping shows with it.

My thinking was dithering was always for rendering kHz rate and not about bit rate so I have only dithered when moving from 48kHz to 44.1kHz when making a "lite" copy for some of my friends' bands.

[aaronji]

It is my understanding that, when reducing bit depth, best practice is to dither to reduce distortion due to quantization error. I don't know whether it is strictly necessary, but it is easy to do, so why not?

[goodcooker]

I don't think I ever noticed that after I explode the polywav in Reaper, the tracks are still 32 bit.  How I did not know this was native behavior is an oversight, even after 6 months of taping shows with it.

My thinking was dithering was always for rendering kHz rate and not about bit rate so I have only dithered when moving from 48kHz to 44.1kHz when making a "lite" copy for some of my friends' bands.

The terms typically used for these two different processes are -

dither - changing bit rate
sample rate conversion - changing sample rate

Here's a good non technical article from Izotope on what these processes are and when they should be used - https://www.izotope.com/en/learn/what-is-dithering-in-audio.html

[Twenty8]

I feel like the implication of the article suggests two renders: one to dither to 44.1kHz and a second for sample rate conversion to 16bit.

Is that the correct way of reading the article?

[goodcooker]

I feel like the implication of the article suggests two renders: one to dither to 44.1kHz and a second for sample rate conversion to 16bit.

Is that the correct way of reading the article?

Dither doesn't apply to sample rate conversion.

You can apply dither (to reduce/change bitrate) and resample (to convert from 48kHz to 44.1kHz) as part of the same render so only one process. I haven't used Reaper in a while but in Wavelab (and other DAWs) it's one process with selections for final format made at time of render.

[BlueSky71]

Is it bad that I have NEVER dithered and record at 32 bit, compress to FLAC 8/24 and upload? I have never had an issue, this is in Audacity BTW....

[wforwumbo]

Dithering has zero effect on sample rate conversion. Dithering when converting sample rates won’t really hurt your tape, but it will add time to the bounce/render when you apply it.

In theory, you want to dither whenever you change bit depth. It helps to mask strange distortions during fade ins/outs, and it technically masks some (usually imperceptible) artifacts when volume is very low. In practice for taping, it doesn’t make a huge difference whether you dither or not. I always dither when going from 24 to 16 bits, if you’re going from 32 float to 24 I’m skeptical anyone would hear the difference between dithered and not dithered.

A good exercise is to try bouncing two files from 32 to 24 bit - one dithered, one not dithered. Especially on fade ins/outs. See if you hear a difference. When I was younger and my hearing tested up to 23k, I could hear it but decided even back then it was a subtle thing that I’d do for polish but wouldn’t stress if I forgot to add in; these days with my hearing only going up to 17k I’m not convinced I could hear it.

[voltronic]

I record 32FP/48kHz and final tracks are 24/48 FLAC, same as BlueSky71. My typical post workflow is iZotope RX (global level adjustments, spectral denoise, other corrections) then Reaper for everything else. I keep everything in the 32FP until final track rendering, and never add dither, unless making 16-bit tracks for CDs. And I haven't done that for ages.