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  #1  
Old 12-09-2009, 09:23 AM
Torchlight Torchlight is offline
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Default I cannot account for this one.....

Last night after a recording session I discovered something a bit strange that may have a very reasonable explanation, but I can't figure it out. I typically use my rackmouonted Lexicon MPX 550 Reverb processor to feed the mix bus while tracking using the 002R's Analog 8 Output, and returning to the 002R via SPDIF. I do this because I don't like using any plugins if I can help it so that I can keep latency to a minimum for the musician, by setting the playback engine at 128 samples. In last night's session something strange happened. After I was done tracking I changed the playback engine to 1024 samples since I didn't need to worry about latency anymore (or did I?). When I did that the MPX 550 reverb return developed a noticeable delay. When I muted the return aux channel the delay went away. I could not account for this and I do not recall ever hearing this before. Also, when I changed back to 128 samples the delay went away. Very weird. Changing the playback engine from 128 to 1024 was almost like boosting the MPX 550 return aux fader by at least 50% - 75%. Does anyone have any ideas?

Torchlight
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  #2  
Old 12-09-2009, 12:49 PM
flommer flommer is offline
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Default Re: I cannot account for this one.....

I'm not clear on your signal chain??:

Protools tracks> analog ouputs on the 002> lex550>spdif inputs 002>main stereo bus..

Are you sending the whole mix through the lex? Or just sends?

Anyway, anytime you send any signal through a A/D or D/A converter, you are incurring the sample latency that you set in PT. If you use both the D/A then A/D you would be doubling the hardware buffer setting (I'm pretty sure). At 1024 samples HW buffer, you would be adding a 46ms delay (if I am figuring all this out correctly) not to mention any latency in the lex itself.

My guess is that the delay was always there, but you weren't hearing it until you increased you HW latency by almost 10x.

Sounds like you need to learn about Plugin/insert delay compensation.

I like to make sure everybody is aware of these videos:

http://www.screencast.com/users/peed...ders/tutorials

The one about hardware insert sounds like it applies to your situation...
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  #3  
Old 12-09-2009, 02:00 PM
Torchlight Torchlight is offline
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Default Re: I cannot account for this one.....

Thanks flommer. I am using the Analog 8 Output not the Analog 1-2 (whole mix) output to send to the lex. The signal chain is set up the correct way. However, I had no idea there was that much latency. I guess I never noticed it before because I have not made the change from 128 to 1024 within the same session. Also I was using a very short reverb preset on the lex known as "Bedroom". I usually use a nice medium plate which maybe doesn't show up so dramatically. In other words the delay may have gotten buried by the reverb tail itself when using a plate. Thanks for the reply!
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Old 12-09-2009, 02:21 PM
flommer flommer is offline
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Default Re: I cannot account for this one.....

Quote:
Originally Posted by Torchlight View Post
Thanks flommer. I am using the Analog 8 Output not the Analog 1-2 (whole mix) output to send to the lex. The signal chain is set up the correct way. However, I had no idea there was that much latency. I guess I never noticed it before because I have not made the change from 128 to 1024 within the same session. Also I was using a very short reverb preset on the lex known as "Bedroom". I usually use a nice medium plate which maybe doesn't show up so dramatically. In other words the delay may have gotten buried by the reverb tail itself when using a plate. Thanks for the reply!
Yes, actually you added to the predelay.. One of those videos talks about that..
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  #5  
Old 12-09-2009, 04:20 PM
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O.G. Killa O.G. Killa is offline
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Default Re: I cannot account for this one.....

Quote:
Originally Posted by Torchlight View Post
Thanks flommer. I am using the Analog 8 Output not the Analog 1-2 (whole mix) output to send to the lex. The signal chain is set up the correct way. However, I had no idea there was that much latency. I guess I never noticed it before because I have not made the change from 128 to 1024 within the same session. Also I was using a very short reverb preset on the lex known as "Bedroom". I usually use a nice medium plate which maybe doesn't show up so dramatically. In other words the delay may have gotten buried by the reverb tail itself when using a plate. Thanks for the reply!
Yeah, I think that's what happened. Also, check to make sure the verb is 100% wet in the lexicon and that it isn't sending any of the dry signal back out with the wet.
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  #6  
Old 12-11-2009, 11:17 AM
Torchlight Torchlight is offline
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Default Re: I cannot account for this one.....

Thanks guys for both replies. Sorry I have not had a chance to reply back until now. I will check the Lex to make sure that it's running 100% wet.
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