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  #1  
Old 08-06-2011, 07:31 AM
wedge wedge is offline
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Default Analog Latency and Delay Compensation

I was looking at throughput latency and found an interesting issue.

Sample rate :96k
H/W buffer 64
compensate after record pass both OFF (for testing purposes)

The session has 2 tracks, and no plugins. I have a spike on track 1. I send this to analog output 5 (DIGI 192), and re record it to track 2 using analog input 1.
Throughput latency shows to be 91 samples.

Switch on Delay Compensation, and the number changes to 219 samples.

Here's the odd part... turn Delay Compensation back off, and the latency remains 219 samples. The only way to get it back to 91 is to either save the session with DC off, and re-open it, or change the H/W buffer to a different setting (also with D/C off).

In short, I can't get delay compensation to ever turn off (in regards to analog throughput) once it's been turned on.

Anyone else seeing this?


PTHD Native 9.0.4
Mac 6 core 3.33. 16GB ram.
OSX 10.6.7
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  #2  
Old 08-06-2011, 02:06 PM
filosofem filosofem is offline
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Default Re: Analog Latency and Delay Compensation

Yep. Pro Tools HD Native 9.0.3 Windows 7 64.
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  #3  
Old 12-05-2011, 12:06 PM
wedge wedge is offline
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Default Re: Analog Latency and Delay Compensation

Two updates down the road and this is still not working correctly... how exactly does one go about reporting a bug?
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  #4  
Old 12-06-2011, 12:23 PM
scottgreiner scottgreiner is offline
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Default Re: Analog Latency and Delay Compensation

Just to add to this - for fun I tried running PT HD 9.0.3 in native to see what happens to delay compensation with different buffer settings. I pulled out my Aurora 16's LT-HD card, stuck in their LT-USB card and relaunched PT in native mode.

Yowza! I couldn't get delay compensation to do anything remotely resembling consistent behavior - even without any analog inserts! I could get two parallel channels to phase cancel-out with the Aurora LT-USB using the time adjuster plugin (one channel with an analog insert, duplicate channel without) but when I entered that number of samples into the I/O settings (which is in milliseconds!? dumb) it was a moving target. Things were changing all over the place! Phasing, flamming, yuck!

Does HD Native show this kind of behavior?! Glad I've got an HD rig.

Oh yeah, forgot: Protools HD2, version 9.0.3, Mac OS 10.6.4
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  #5  
Old 12-08-2011, 12:01 AM
kcfroines kcfroines is offline
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Default Re: Analog Latency and Delay Compensation

Quote:
Originally Posted by wedge View Post
I was looking at throughput latency and found an interesting issue.

Sample rate :96k
H/W buffer 64
compensate after record pass both OFF (for testing purposes)

The session has 2 tracks, and no plugins. I have a spike on track 1. I send this to analog output 5 (DIGI 192), and re record it to track 2 using analog input 1.
Throughput latency shows to be 91 samples.

Switch on Delay Compensation, and the number changes to 219 samples.

Here's the odd part... turn Delay Compensation back off, and the latency remains 219 samples. The only way to get it back to 91 is to either save the session with DC off, and re-open it, or change the H/W buffer to a different setting (also with D/C off).

In short, I can't get delay compensation to ever turn off (in regards to analog throughput) once it's been turned on.

Anyone else seeing this?


PTHD Native 9.0.4
Mac 6 core 3.33. 16GB ram.
OSX 10.6.7

you need to setup your hardware insert delays in the i/o setups page. for it to work you need to have the same I/O channel for the hardware insert (going out output 5 needs to be returned to input 5 for example)
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  #6  
Old 12-08-2011, 06:49 PM
wedge wedge is offline
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Default Re: Analog Latency and Delay Compensation

Quote:
Originally Posted by kcfroines View Post
you need to setup your hardware insert delays in the i/o setups page. for it to work you need to have the same I/O channel for the hardware insert (going out output 5 needs to be returned to input 5 for example)
I'm probably not explaining it very well, but this has nothing to do with hardware inserts. It's about delay compensation not being able to be turned off once it's been turned on - in regards to roundtrip (analog input to output) latency.

DC off:
latency is 91samples

turn it on:
latency is 219 samples

turn it back off:
it's still 219

you can't get back to 91 samples unless you toggle engines, or close and reopen your session.
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  #7  
Old 12-10-2011, 01:27 AM
scottgreiner scottgreiner is offline
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Default Re: Analog Latency and Delay Compensation

Quote:
Originally Posted by kcfroines View Post
you need to setup your hardware insert delays in the i/o setups page.
I know your info is not directed at me, but FWIW, I've found that the I/O insert delay setting is a moving target depending on the buffer size, the day of the week, and whether the moon is in retrograde. Two days ago for 1024 buffer the delay setting was 1.88ms; and 1.9ms for 256 buffer. Yesterday it was 1.94ms for a 1024 buffer (it WAS a full moon after all). Plugin ADC works perfectly as expected.

This is using core audio with a Lynx Aurora16 and a LT-USB card - not HD Native card. Even when I do find the magic I/O delay number for any given day, it still will only null to about -30dB. Using the same setup in Logic with their I/O plugin with the "Ping" nulls down to about -70dB. Better, but still no where near the performance of my HD rig.

Talking with someone who has the HD Native card, they've stated that this moving target scenario doesn't exist. I'll have to get a demo of the HD Native and see...
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  #8  
Old 12-10-2011, 12:45 PM
filosofem filosofem is offline
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Default Re: Analog Latency and Delay Compensation

Wedge, why do you need to toggle ADC?
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  #9  
Old 12-23-2011, 06:15 AM
wedge wedge is offline
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Default Re: Analog Latency and Delay Compensation

Quote:
Originally Posted by filosofem View Post
Wedge, why do you need to toggle ADC?
I will sometimes temporarily turn it off to get the shortest latency in the artists phones - for doing a quick overdub for instance. Simply by having it on, you add an extra 64 samples to what they're hearing in the cue at 44.1/32buffer (128 extra samples at 96k/64 buffer). These times increase proportional to PB engine times.
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  #10  
Old 12-23-2011, 12:15 PM
filosofem filosofem is offline
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Default Re: Analog Latency and Delay Compensation

It's my understanding this is by design.
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