Nomenclature

[vikingthor]

Originally Posted by CME

It's been covered but to sum it up, there are two separate subjects of bit depth.

1. The bit depth the app is using for ram allocation.

2. And the bit depth of the audio.

This first is easily understood. The other is a bit deeper.

I know this is in the live sound side, and I'm not familiar with the s3l. But as far as I know, there are very few 32-bit converters. Float or fixed point. So what's coming off the interface, to be processed/recorded, is usually 24-bit fixed. You can record a 32-bit float file. But if you're recording straight off a converter, you're wasting hard drive space.

However once you process the audio you usually have more than 24-bits. So that's where the 32-bit can come into play on a single channel. So if you're recording post processing, 32-bit float may make sense.

And I'm not sure, but I believe in past versions of pro tools the audio had to be dithered/truncated to 24-bits before passing on to the next plug-in, buss send, master fader. I have no idea about their live mixers.

I'm hoping that we now have full 32-bit float audio paths in Pro Tools. That would reduce the amount of truncation/dither going on. But I really don't know If we do.

The next thing is the bit depth of the summing mixer. Pro tools has had a 64-bit float summing mixer since pro tools 9. With the exception of TDM rigs. Those have a 48-bit fixed mixer. Once you go adding up all these 32-bit streams you're going to have more than a 32-bit sum. So that's why you're mix engine is usually a higher bit depth than the audio files. I think the venue rigs probably use a 48-bit fixed, while the s3l uses 64-bit float. But I really don't know. That's just going off them being based off TDM and HDx respectively.

Hope all of that makes sense and helps explain some things.

Yes! Nice explanation.

[morrison.ece05]

Thanks CME for the explanation.

I guess my last question was a little more elementary and just practical. Basically I was wondering whether you would load the 32-bit AAX plugin or the 64-bit AAX plugin on the S3L. Before there was just TDM that was loaded onto the live console, not 32-bit TDM or 64-bit TDM versions out.

I understand that the software for ProTools can be 64-bit and thus use more of the available RAM, but I wasn't sure if the Venue Software for S3L would require the use of 64-bit plugins because the Venue Software is built as a 64-bit application (not sure if it is or isn't) or if it the Venue software is just a portal to manipulate what is going in the DSP and communicate to the other peripherals. The plugins may not be dependent on how the Venue Software was built.

Brian

[CME]

Well for that question you'll have to get an answer from someone else. I'm really not familiar with the s3l and whether it uses 32 or 64 bit plugs.