• Registered: 2020-08-27
  • Posts: 3

Topic: How to check incoming optical signal bit depth?

Hi! I'm new, hope I'm posting in the correct forum.

I've hooked up a TASCAM MD-350 output to an RME Babyface (old generation), and I'm trying to figure out:

How do I check/display the bit depth on the signal? Using Reaper I can record at 16/20/24 bit, but I'd like to figure out what the devices have negotiated, for optimal quality.

My own googling led me to Digicheck and these forums. Unfortunately, I'm running OS X Catalina (screw you Apple for prematurely dropping 32-bit support 'just because'), and Digicheck NG doesn't yet have Bit statistics.

Is there any other way to figure this out? Would it be easier if I dug out a Windows PC?

Thanks!

2 Reply by ramses (edited by ramses 2020-08-29 19:34:14)

  • ramses
  • DAW Mastermind
  • Online
  • From: UTC+1
  • Registered: 2012-10-14
  • Posts: 12,874

Re: How to check incoming optical signal bit depth?

Wikipedia - ADAT
https://en.wikipedia.org/wiki/ADAT_Lightpipe

[...] Lightpipe signals are transmitted at 24 bit resolution, no matter what the depth of the audio; information is contained within the Most Significant Bits and the rest of the bits remain a string of zeros. [...]

No worries, ADAT will always transfer 24 bit, if the signal doesn't have this but depth then the rest of the bits are filled with zero .. or in other wordst, there will be no quality loss..

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2020-08-27
  • Posts: 3

Re: How to check incoming optical signal bit depth?

Interesting! But wouldn't I still want to know the depth of the audio part of the signal, so that I can record at that depth? Let's say the minidisc deck is sending 16 bit audio over ADAT optical. According to the spec, 8 bits of padding zeros would be added. Let's say Reaper is recording at 24 bit depth. Are zeros being unnecessarily stored in the files? Or in the worst case, is Reaper somehow able to determine the significant audio bits, then converting the 16 bits to 24? I'm trying to avoid both conversion, and unnecessarily large files.

  • ramses
  • DAW Mastermind
  • Online
  • From: UTC+1
  • Registered: 2012-10-14
  • Posts: 12,874

Re: How to check incoming optical signal bit depth?

Sorry, but you are worrying about it completely unnecessarily. Today, everyone records with at least 24 bit, if not 32 bit.
This is simply to get a higher dynamic and SNR during the mixing and mastering phases of the project.
Then VSTs can work more accurate on the audio material until the final downmix to CD or whatever format happens.
And sorry again, even with Gigabit and Terabit hard drives and SSDs, it seems a bit ridiculous to start counting the bits now.
There are many other things more in the whole area that I would worry about more than 16 vs 24 bit and file sizes.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Registered: 2020-08-27
  • Posts: 3

Re: How to check incoming optical signal bit depth?

Alright. I really appreciate your responses!