Can Someone Clarify I/O Settins "ADC After Record Pass"

[25ghosts]

Hi - the manual is pretty unclear on the I/O Settings' two options under Input and output. The options is for the ADC - whether to apply ADC after record pass.

I have tried enabling and disabling both but I dont seem to get ANY difference when recording. Still, I would really appreciate if someone would take the time and explain to me exactly what those options are instead of the manual's lame description.

Thanks in advance

[25ghosts]

Anyone ?

[EvilElfBoy]

Are you experiencing latency when you are recording through the interface? As soon as you put a track into input it should go zero. then apply ADC if there are plug's on the track that you just recorded. Not working that way?

[25ghosts]

Originally Posted by EvilElfBoy

Are you experiencing latency when you are recording through the interface? As soon as you put a track into input it should go zero. then apply ADC if there are plug's on the track that you just recorded. Not working that way?

Yes it is - and always has been. With or without that weir option in I/O setup. It makes no difference (obvious anyway) whether they on or off. That is why I would like to know exactly what there are doing that normal adc aint doing

[EvilElfBoy]

Oh I see what might be the problem, the apogee and the magma. How much latency are you getting? I can try this at home for you when I get on my 96 I/O to see if it nulls. That option may not seem like its working because of the additional latency of those 2 hardware pieces.

[StudioRhythm]

I always assumed it corrects for interface (converter) latency on the D/A/D round-trip, probably set for the 192 I/O. I tested it at one point a while ago and there was some small difference in where the audio is placed on the timeline with the different options on and off, maybe 20-40 samples or so or possibly even less, nothing much to worry about in the grand scheme of things but would be interesting to know exactly what the deal is....

The way to test this is with a D/A/D loop, which if you think about it is also kind of the best-case scenario of what you'd do when you double a part, so conceptually it's a good stand-in for an overdub situation.

[EvilElfBoy]

Yeah I think that's right. Conceptually I think it is making up for when the A/D/A conversion happens and putting the recording when it was heard and played, I think it just does the math to but it back in time order. It has nothing to do with ADC at all. Interesting, you think it has to do with D/A/D?

[StudioRhythm]

Originally Posted by EvilElfBoy

Interesting, you think it has to do with D/A/D?

Well, in some ways it's mostly semantics and is equivalent either way, but yeah, it'd really be D/A/D rather than A/D/A as I look at it. The goal is to line up all the audio within ProTools in an overdub situation. So, first the audio that's being monitored leaves PT, is converted from D to A, the performer plays in sync with it (hopefully) and his performance is converted from A to D, so that'd be D/A/D.

Of course, all this is assuming that's what this function really does...

[25ghosts]

Originally Posted by StudioRhythm

Of course, all this is assuming that's what this function really does...

Exactly my words.

I dont KNOW what this thing does.

D/A/D roundtrip 1st class takes 1.63 millies on my rig.

In order to test what really happens I have tried this:

On 10 drum tracks I inserted on each an L3 TDM Limiter to get some real delay. The 10 tracks went individually out to my board and were recorded back into pt on a bus. this way i could analyze the delay occurring.

1) Rec with Forced ADC
2) REc with standard ADC
3) Rec with outputs pass on and standard adc
4) Rec with inputs pass on and standard adc


the ONLY thing changed, was the monitor situation during record. ALL 4 stereo recordings lined up at the same starting point.

I am REALLY dumb in math so it could very well be that I am missing the "total obvious" if so - then someone - please - help me



1)

[Frank Kruse]

AFAIK this applies the insert-delay (if set) in the i/o setup. If you set those to 0 there won´t be a difference between "compensate for input/output delays" set to on or off.

This is to compensate for outboard-gear connected via PT´s I/Os defined as hardware inserts. Otherwise there is no way for PT to "know" wich out actually goes to a monitoring out or an outboard-unit that applies a delay and comes back into PT.

Or did you set it up that way?

f.