severe LATENCY on AUX problem.

[BusyBoxSt7]

I used to run a digi 002, pt le 6.9 on a G5 dual 2.0 and sometimes had to run at 2048 hardware buffer to keep it running smooth during a mix.. never had severe latency problems. But....

current system
HD1 accel pcie, PT 7.3.1
mac pro 2.66 w/ 3 GB ram
lynx aurora 16 (love it!), NO digi 192/96 needed of course
running both TDM and RTAS

THE ISSUE
Any time I use an aux channel (say I'm affecting both OH channels the same) to put plugins on, I get severe slapback-ish lag on the aux. I mean you can watch the meters move obviously behind their source track's meters. The only way to reduce it is LOWERING the hardware buffer (in playback engine dialog) to 512 or even 256 sometimes. I find myself mixing at 256 then upping it to 512 to get through a bounce. I thought the hardware buffer worked the other way around???

The auto delay compensation (ADC) has NO obvious effect on it, regardless of it's setting.

Somebody shine some light on this oddity.

PS. it's been doing this ever since I bought the HD1.

[crizdee]

THE ISSUE
Any time I use an aux channel (say I'm affecting both OH channels the same) to put plugins on, I get severe slapback-ish lag on the aux. I mean you can watch the meters move obviously behind their source track's meters. The only way to reduce it is LOWERING the hardware buffer (in playback engine dialog) to 512 or even 256 sometimes. I find myself mixing at 256 then upping it to 512 to get through a bounce. I thought the hardware buffer worked the other way around???

The auto delay compensation (ADC) has NO obvious effect on it, regardless of it's setting.

Somebody shine some light on this oddity.

Hi,

What setting have you got the ADC set to? short? long? (in playback settings)
What plugins are you using on the aux, and are you mixing TDM and RTAS by any chance!
What colour is the reported delay comp showing for the aux channel?
Are you using RTAS plugs, then changing the buffer size?!

Chris

[BusyBoxSt7]

-ADC I've tried at all 3 settings to NO effect.

-I'm not "mixing" TDM/Rtas/TDM/rtas, but am sometimes using say: rtas->rtas->tdm->tdm... It screws up though even w/ just one RTAS on an aux (like AltiVerb6). But I don't think it's related to AV6 cause it does it w/ auxs that don't have it.

-Where do I find the color for Delay Comp? (I just switched from an 002 recently)

-About "RTAS then changing the buffer size" what exactly do you mean? I have to right now sometimes cause anything over 512 (or even 256 w/ some mixes) get lagged but I'll need more than that to bounce down. Perhaps using the old "use a master aux and rerecord to a stereo track in PT" would allow me to avoid needing to change it to bounce. BUT, please explain what the problem is w/ changing the buffer. Obviously it's supposed to be changed between tracking (set low) times and mixing times (supposed to be set higher although mine obviously doesn't work right or I don't) during a session.

thanks for your help w/ this HD newby. it'd be awesome if they put THIS stuff at the beginning of a method one DVD! haha.

[crizdee]

-ADC I've tried at all 3 settings to NO effect.

-I'm not "mixing" TDM/Rtas/TDM/rtas, but am sometimes using say: rtas->rtas->tdm->tdm... It screws up though even w/ just one RTAS on an aux (like AltiVerb6). But I don't think it's related to AV6 cause it does it w/ auxs that don't have it.

-Where do I find the color for Delay Comp? (I just switched from an 002 recently)

-About "RTAS then changing the buffer size" what exactly do you mean? I have to right now sometimes cause anything over 512 (or even 256 w/ some mixes) get lagged but I'll need more than that to bounce down. Perhaps using the old "use a master aux and rerecord to a stereo track in PT" would allow me to avoid needing to change it to bounce. BUT, please explain what the problem is w/ changing the buffer. Obviously it's supposed to be changed between tracking (set low) times and mixing times (supposed to be set higher although mine obviously doesn't work right or I don't) during a session.

thanks for your help w/ this HD newby. it'd be awesome if they put THIS stuff at the beginning of a method one DVD! haha.

Hi,

The track that has the greatest amount of delay compensation is displayed in orange (the delay comp number that is) and when a track has exceeded the delay compensation it turns red.

The amount of delay caused by RTAS plugs is linked to the buffer setting!! so changing the buffer after you've started to mix, will cause the rtas plugs delay to change. this is especailly a problem when mixing and matching RTAS/TDM/RTAS etc. basically if you double the size of your buffer the delay for RTAS plugs also increases by 50%

Chris

[BusyBoxSt7]

The track that has the greatest amount of delay compensation is displayed in orange (the delay comp number that is) and when a track has exceeded the delay compensation it turns red.

The amount of delay caused by RTAS plugs is linked to the buffer setting!! so changing the buffer after you've started to mix, will cause the rtas plugs delay to change. this is especailly a problem when mixing and matching RTAS/TDM/RTAS etc. basically if you double the size of your buffer the delay for RTAS plugs also increases by 50%
Chris

Where is the color for delay comp shown? i.e. "delay comp #"

-If changing the buffer setting messes everything up, is it always necessary to finish all tracking before mixing (since you may have to lower the buffer for mixing)?

-So what is the workaround? What should I set the buffer to before starting mixing? Does it have to somehow match up w/ whether the TDM is set to 'none', 'short', or 'long'?

-I thought delay compensation (one of the main selling points of HD) was supposed to be automatic. Does it not work w/ RTAS?

Sorry, I'm just confused by all this and haven't found any clear explanation in my reference guide. My frustration's not w/ you of course. Thank you for the help.

[Stig Eliassen]

It sounds to me that you haven't turned ADC on? I mean, you've obviously set it to either short or long in the playback engine, but have you checked it under Options (menu) > Delay Compensation?

[jjhuntfox]

Based on the Tapeop thread you are using Altiverb 6. I have found Altiverb 6 to be very buggy and I have gone back to Altiverb 5. I had some severe latency with AV 6 but there were other problems too. It sounded like a delay / reverb box. (Yes I muted the direct signal because I use it on an AUX track) It lost all of my AV 5 presets thank goodness they came back with AV 5.

Remove AV 6 and see if that fixes the problem. You can re-install it later if it isn't.

[BusyBoxSt7]

huntfox:
AV6 could have issues but I've got more general issues to fix first.

PT Lover:
nope, delay comp checked on at that location as well. great idea though.

SOME CONCLUSIONS:
did find the delay comp readouts under "view", "edit window". I had no clue about that (thanks guys!). Now I understand the way buffer affects the RTAS (well, in auxs). I use RTAS on the master which puts it into the red but that's fine (right?) cause it all comes out equally late.

"new" questions:
From the delay comp meters I see that putting an RTAS on an AUX (at least a drum one) really ups the delay. Is this because the aux's delay is somehow multiplied by the number of channels feeding it or what? I mean by comparison the RTAS on individual tracks show minimal delay, like "1" or so. Also, while the buffer really effects the aux rtas plugs, it does nothing to the individual tracks that have rtas on them.

samples:
-on an aux: tdm massey CT4= "5", tdm L2007= "133", rtas 2007= anywhere from "612" to "15000" depending on the hardware buffer.
-on an individual track: tdm 2007= "133", rtas= "128" regardless of hardware buffer

[crizdee]

Now I understand the way buffer affects the RTAS (well, in auxs). I use RTAS on the master which puts it into the red but that's fine (right?) cause it all comes out equally late.

Well, yes and no!! best to disable the ADC for the master fader? command+control+click on the delay number to disable it.

What you have to remember when using aux/busses is this, the delay from the tracks feeding it are added to the delay caused by the plugs added to the bus!! which is added to the delay on the mix bus!! track delay add to aux delay add the mix bus delay = red delay = non delay compensated = out of time = out of phase! Houston we have a problem.

Using RTAS on Aux channels creates a lot more delay than using them on a track, as you have discovered.

Try and take an hour today to read the manual within PT you have a help menu. there you will find the reference manual with a search facility

Chris

[meech]

RTAS plugins on Aux tracks in HD always produce latency. The aux (I believe) is handled by the HD cards' dsp, and then to use RTAS the signal has to go back to the computer, before going out again to the cards. Unfortunately TDM plugins are the only ones that work without extra latency on Aux tracks.