Nomenclature

[morrison.ece05]

Is there a nomenclature chart that explains all of the different terms used for ProTools 10/11 and the S3L?

For example, I am confused as to the use of the 32-bit vs. 64-bit terms to describe what is going on in the background. ProTools 11 is said to be 64-bit, but the specifications on the website say it is sampling at 32-bit floating point. Is the 64-bit just describing the architecture that ProTools is running on?

I ask the first set of questions to see if it relates to the S3L in the same way. In other words, does the S3L runs on a 64-bit architecture, but the sample rate is only 32-bit floating point?

If 64-bit is suppose to be better and more powerful then why wouldn't we sample at 64-bit? Maybe, the hardware isn't capable of 64-bit sampling, maybe it doesn't matter as it pertains to sound quality? Anyhow, just trying to satisfy my nerdy curiosity. Thanks in advance.

Sincerely,

Brian

[Greg C]

When referring 32 vs. 64 bit architecture for software, they're usually talking about the maximum amount of RAM that the application can address. 32 bit addressing limits you to a max of 4GB of RAM usable by the application regardless of how much you have installed in your machine. With 64 bit applications running on a 64 bit machine (OS and processors), you can address a theoretical maximum of 16 exabytes of RAM which is 16.7 billion gigabytes. IOW, a 64 bit setup can use as much RAM as is available on the machine.

32 bit float processing has nothing to do with memory addressing, it has to do with the actual audio processing and offers more then enough dynamic range to ensure audio dynamics are the best they can possibly be. The theoretical dynamic range of 32 bit float is > 1000dB.

[n8white]

Wow thanks Greg. I've always wondered about the dynamic range of 32 bit float (the floating integer thing screws with my math). There are some "other console manufacturers" that make it sound like that isn't enough for the live environment. I wonder if there are many PAs that can replicate more than 1000Db of dynamic range. I'm sure someone on here is smarter an me and can chime in.

[Greg C]

The only thing that can replicate the dynamic range of 32 bit float is something like a star exploding The loudest PA systems can possibly reach 150dB peak at 1 meter in theory. But dynamic range means the range between loudest and softest sound above the noise floor. So that puts you back down in the <100dB of actual dynamic range.

[xcx]

as far as i know, the 32bit float processing is still a 24bit processing (as 24bit equals 144db dynamic range which is basically what a human is able to recognize) where the new 8 bit (24+8=32) will be added on top as extra dynamic range.

now the point of adding bit is not to increase loudness level, as inputs and outputs still remain on 24bit (dont know about s3l... but usually an interface relates to 24 bit in I/O when the DAW is on 32bit float), but to add extra dynamic range in internal processing. what means for example you are basically not able to clip a submixbus when adding multiple inputchannels to that one bus. as you gain +6 db when you add the same signal together you would breach the usual db range within a 24bit processing when having two signals recorded at -5db/fs. with the 32bit float bits will be added to increase dynamic range to not clip the bus.

please feel free to correct me if i'm talking bull***t right now.

[Voice Of Truth]

How to say without falling too much into details...

32-bit float (full info on wiki: http://en.wikipedia.org/wiki/Single-...g-point_format) basically has 24 bits of significand digits (treat it as usual 24-bit fixed-point) + 8 bits of exponent. And exponent extremely increases dynamic range. So 32-bit floating point has much-much high dynamic range than 24-bit or even 32-bit fixed point.

For 32-bit float range is around 1680 dB: http://www.macprovideo.com/hub/pro-t...ng-point-audio

[n8white]

Now That makes sense. And yah, that's plenty of space. Thanks.

[morrison.ece05]

Is the S3L system a 32-bit system or a 64-bit system when it come to the AAX plugins? The website says plugin support is AAX DSP, but doesn't designate 32 or 64-bit.

https://www.avid.com/US/products/S3L...Specifications

[xcx]

DSP = HDX 32 bit float

...says everything about how plugins being handled.

[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.