• Registered: 2011-10-28
  • Posts: 33

Topic: Totalmix for monitoring/volume control - bit depth question

I've owned a UFX for many years but only really used it for input/recording.

Looking at a workflow that would use the UFX for monitoring as well, and just want to make sure I understand the tech and gain staging, with regard to using Totalmix as a digital volume control. (Apologies if this has been covered, I didn't find anything relevant quickly.)

Totalmix output is 24bit (per the hardware). But the totalmix faders are 16bit.

If I've got a 24 bit file playing, and need to bring the monitor fader/volume down about 10 or 15db for normal working levels, I'm losing about 2 bits of depth, correct? (6db per bit....) Or is it more because of the faders being only 16bit? I think that's where I'm confused a little bit. Or is it always going to be 24bit because it's throwing out the LSB (and Totalmix is actually working at what, 40bit fixed?).

I admit this is where my digital audio understanding gets a bit murky, so would appreciate any and all clarification.

Thanks!

  • Registered: 2016-10-17
  • Posts: 19

Re: Totalmix for monitoring/volume control - bit depth question

The 16 bit fader resolution only affects how finely you can make a gain adjustment on your signal. BTW, 16 bits is lots, as I believe Logic uses 7 bit faders and a non linear mapping (faders have their finest resolution around 0). So, the 16 bit fader resolution is a bit of 'red-herring'; it's a non-issue.

Because totalmix is working internally at a high resolution, you're only likely to lose some bit depth if you've reduced the volume on the final conversion of your signal back to analog, or if you're sending a digital output to some other device for recording (Dat deck, etc).

Hope this helped...

Cheers

Kris

  • Registered: 2011-10-28
  • Posts: 33

Re: Totalmix for monitoring/volume control - bit depth question

Thanks, this clears up the fader bit (ha!).

So to help me understand Totalmix math better: So let's say I give it 24 bit audio at unity gain. Do those 24 bits fill up the top of the range or the bottom? I'm guessing the bottom? So then if you add signal or gain, additional bits are used, obviously. But on the output, it's limited to 24 bits, so does it take the 24 top bits, bottom bits, or something else? And conversely, what about taking bits away (i.e turning down the volume).

Ultimately the question is: if I take a 24 bit signal, turn the gain down by 12db (2 bits) in Totalmix, does it then output what is effectively a 22 bit signal? I think the answer is obviously yes, but want to make sure my thinking is correct.

Thinking here... I wonder if I can test this via a digital loopback with digicheck. Might be a project for later tonight.

  • Registered: 2011-10-28
  • Posts: 33

Re: Totalmix for monitoring/volume control - bit depth question

I wasn't able to figure out much with a loopback, as it seems (logically) that no matter the audio content, the bit depth remains steady at 24bit.

So any additional clarification on this would be greatly appreciated.

Thanks!

  • vinark
  • DAW Mastermind
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  • Registered: 2009-06-05
  • Posts: 2,658

Re: Totalmix for monitoring/volume control - bit depth question

This has been discussed many times and there is some consensus. Digital gain changing is 100% fine unless it is very very much. What very much is exactly is another question but it is not 15db.
It is very obvious with something like -90db but not so with -60db, not that that is an ok value (if you need -60db it would mean your monitors are not set up correctly). Of course analogue gain would be ideal.....but to do that right is very very expensive so in reality digital is better then affordable analogue.
To confuse things, I use an affordable mackie Level Pilot, because I like not having to use a mouse or a device. Just a knob, always within reach...
Better not think about these things to much. Digital can make us very neurotic: OMG I have lost a bit ;-)

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • Registered: 2011-10-28
  • Posts: 33

Re: Totalmix for monitoring/volume control - bit depth question

Thanks Vincent. With your encouragement I've done some more searching of the archives and have filled out my knowledge base.