• Registered: 2012-11-12
  • Posts: 5

Topic: Phase alignment troubles with FF800 loopback between adat/analog/digit

Hi there,

I'm reamping a lot and I wonder if it's possible to implement an automatic delay compensation for digital and adat inputs. Phase alignment is something that is a problem in digital DAWs and the mere fact that you cannot reliably listen to what you are doing when reamping is a pain.
I use a UA 710d for additional inputs and I have a Behringer ADA8000 for even more additional outs in case I need them (and right now I do), but even with just just a fireface I would have trouble.

How great would it be if we could listen, record, use different hardware all without latency differences? Awesome, right? Is it possible to implement this?

To demonstrate my setup:
listening to the inputs through total mix when routing through different outboard

out and back through latency
fireface digital - fireface digital = 4 samples
fireface analog - fireface - analog = 76 samples
behringer - behringer = 69 samples
fireface - UA710d = 47 samples

re-recording latency
fireface digital - fireface digital = -72 samples
fireface analog - fireface analog = 0 samples
behringer - behringer = -8 samples
fireface analog - UA710d = -29 samples

(info: phase problems get really annoying above 3 samples difference -just take a mono sound source on a stereo track and delay one side with 4 samples and listen what happens- this is the problem)

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,783

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

The differences have to do with the various converters and their individual conversion latency. This is not about analog or ADAT/SPDIF.

Also, while the difference may be audible if you mix identical signals that went through different signal paths, it will not be noticeable with discrete signals. So you only need to make sure that if you want to run one signal source through more than one external device, make sure it only uses one converter.


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

RME Support's Website

  • Registered: 2012-11-12
  • Posts: 5

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

Hi Daniel,

Thanks for your reply. Actually, the problems I'm having have to do with the phase difference in recording latency opposed to listening latency, next to the different latency issues caused by different hardware & the fact that digital out-in re-recording results in a 72samples early recording ( and that is actually an analog vs spdiff i/o problem, and yes, I know that that's normal).

The problems I'm having are in a nutshell 2:

1: I'm reamping a vocal through an amp. The amp signal is added to the original, not replacing it. In order to hear what I'm doing I have to monitor the reamped signal through totalmix. Problem: the phase will be different then the actual recording, so I need to adjust and have to guess my settings a bit because of the phase distortion.

2: I'm summing part of the mix through an old studer mixer. I rerecord stems from it. I do not want the fx on the same stem, so I rerecord (print) the fx through spdiff to make the recording process simpler. Now my fx are 72 samples early which is a problem (think modulation fx) so I have to manually correct that.

Obviously 1 is a far bigger problem then 2 (and I'm not taking into acount that I'm using different converters which makes stuff a lot more complicated). But my actual question: is it possible to implement adjustable latency per output type to compensate for that? I didn't do the math but it would be extemely handy in the streamlining of a serious DAW setup. Just wondering.
I'm on a Mac pro with logic 9 btw.

Regards,
Budy

4 Reply by Wiz (edited by Wiz 2012-11-12 23:12:30)

  • Wiz
  • AD/DA expert
  • Offline
  • Registered: 2007-07-04
  • Posts: 69

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

I dont know if this helps you, but I put a single "Tick" on the track I am reamping.   Then I record this Tick as part of the reamping processs, it can be at the end of the track if you like.  Then I simply realign these in Logic after the reamp.  Sample accurate. Wouldnt matter how many convertors it went through.  Hope it helps.

cheers

Wiz

  • Registered: 2012-11-12
  • Posts: 5

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

Hi Wiz,

Thanks for the reply. I've got everything noted so in the end I'm able to compensate for all of it. I cannot listen to my reamping/ summing mixer adjustments without latency issues, there's no easy work around I can think of. I'm just curious how hard a software adjustment tool would be to build in, so guys like me can make a custom compensated environment.

A good tip though!

Regards
Budy

  • Registered: 2012-11-12
  • Posts: 5

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

Dove into my setup today. So, what I have to do now is forget using Totalmix when reamping and use Logic's i/o plug (totally forgot about that one). It's ping function/ manual latency control lets me monitor send/ returns in phase and as a bonus I don't have to switch windows. But I still think it would be pretty convenient to have this latency adjustment available for Totalmix wink

  • From: Houston, TX
  • Registered: 2007-05-11
  • Posts: 1,191

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

I believe this would either require some DSP in TM, or would have to be done in ASIO.  The UFX doesn't have any DSP (no delay capabilities that I'm aware), and unfortunately I don't believe ASIO supports such features.

Sounds like you got it sorted with Logic.  Another way around this is to loop the "dry" signal through a similar DA>AD loop as the Re-Amp so the delays end up being sample accurate that way (monitor the DA>AD return of the dry signal when tracking, but use the original dry track in the mix as it can be aligned "after the fact").

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8
  • Registered: 2012-11-12
  • Posts: 5

Re: Phase alignment troubles with FF800 loopback between adat/analog/digit

Hi Randyman,

yup, you could be right. I'm sorted out for now although the offset of a recorded bounce was something like 1194 samples. Anyway, if it's consistent I can make presets for the i/o plug and the sample delay plug and be done with it 8) Most important thing is I can hear what I'm doing now & the A/B-ing is way faster this way when using my Studer desk.