AAX Mixer Plug-in, Dithered?

[bugnut]

I am wondering if the mixer.aax plug-in is a dithered mixer?

[JFreak]

No reason. Dithering applies to fixed-point math, and the new Mixer deals with floating-point math (which is kind of dithered all the time).

[Bob Olhsson]

Originally Posted by JFreak

No reason. Dithering applies to fixed-point math, and the new Mixer deals with floating-point math (which is kind of dithered all the time).

This is true however almost all high quality D to A converters and all AES/EBU,SPDIF and MADI connections are fixed point so dithered outputs make an audible improvement to high quality audio.

The good news is that every single plug-in no longer needs to be dithered which was the case with TDM. The bad news is that thus far we have no zero latency 24 bit dither-only plug-ins.

[nst7]

What is the benefit of zero latency on something like that?

[Bob Olhsson]

Low latency is important for overdubbing and virtual instruments.

[JFreak]

Originally Posted by Bob Olhsson

Low latency is important for overdubbing and virtual instruments.

And live projects. Myself, I do at least half of my work in front of live audience. Latency is very important, first and foremost because artists suffer if it's too much, and also whatever latency the DAW produces is kind of a "predelay" or "distance from speakers to the band, so everything more than 10ms is definetely too much. I would prefer 3-6ms but if I need to stretch it usually 6-10ms is usable as well.

[JFreak]

Originally Posted by Bob Olhsson

however almost all high quality D to A converters and all AES/EBU,SPDIF and MADI connections are fixed point so dithered outputs make an audible improvement to high quality audio

True, but that is DA converter implementation and does not concern the PT Mixer.

[nst7]

Guys, I know what low latency is. I'm asking why you would need a dithering plugin to be low latency, when it's used for your final bounce down to make your CD. Maybe you're talking about another use for dithering and I'm not understanding what you're saying.

[JFreak]

I have dithering on at all times, so it needs to be low latency If it's not, I cannot use it.

[Bob Olhsson]

Originally Posted by JFreak

True, but that is DA converter implementation and does not concern the PT Mixer.

The Pro Tools mixer still needs to get to a D to A in order to be heard which means it must somehow get truncated to 24 bits in order to reach one. The only choice we have is between letting it distort or adding just enough noise to toggle the bottom bit which is less audible than allowing the audio signal to toggle it.

Very few chips accept a 32 bit float signal and I understand those that do are typically found in cell phones. As far as I understand the connection between an HD card and an HD interface is 24 bit fixed. In the real world there simply aren't any top quality converters that are implemented to accept 32 bit float.