No more delay compensation when using TC PoCo or UAD1?

[Paul]

When using a, let's say, equalizer plugin from my UAD-card (or TC PoCO), there is a clearly noticeable delay added to the track. I can't remember if this was always so but I'm pretty sure that it was ok before.

Am I missing some sort of a setting?

[Jerm]

I am not familiar with the card you mention. However you can reduce latency by lowering the audio-buffer-packet-size in the device options of the digital audio setup dialog. Note that lowering the packet size creates a higher burden on CPU.

[Paul]

It's the TC Electronics Powecore card/Mackie UAD1 card. When I'm using a native plugin, there's no latency but when I use a plugin from one of these two cards there is.

Like I said, I can't remember that this delay problem was there before.

Maybe I'll try changing the packet size but it's already pretty low: 384 - 8.70 ms.

[Scoot]

I would have thought it had to do with the route it was taking.......


if you place an effect on a track but listen to the dry signal as well, you can hear the difference between the 2.........the effect usually isn't instant.

If you were recording the signal would audio track alignment in the advanced digital audio setup solve the problem?

[Jerm]

When I'm using a native plugin, there's no latency but when I use a plugin from one of these two cards there is

If you mix the audio to a new track, view the two tracks as panes in the graphic editor and zoom in all the way, is there an offset in the audio that you can see? If yes, how many samples is it?

[Paul]

If you mix the audio to a new track, view the two tracks as panes in the graphic editor and zoom in all the way, is there an offset in the audio that you can see? If yes, how many samples is it?

I imported a loop on track 1, added the UAD1 Cambridge plugin, mixed the audio of this track to track 2. I can clearly see an offset. When I select that offset in track 2, in the graphic editor window (top left corner) it says "1:01:40" (with PPG set at 384) and "2120". I'm guessing that the last number is the number of samples, right?

[Jerm]

It sounds like either the plug-in is not be publishing its delay properly or perhaps Metro is not compensating properly. What version of Metro are you using? Are these VST plug-ins?

[Paul]

I'm running Metro 6.3.1.1. The UAD plugins are AU (I don't have the VST versions installed). I've also tried it with both the AU and VST versions of the Powercore. In both cases there is an offset but it's not as big as with the UAD card:

AU: about 1166 samples
VST: about 1040 samples

[Jerm]

I have verified that Metro plug-in delay compensation is working and it is. Perhaps you should contact the manufacturer and ask them if they are publishing the AudioUnit kAudioUnitProperty_Latency correctly. I will also try to contact them.

[Jerm]

That is weird that the samples are different. According to the powercore website:
"How much latency do the plug-ins running on PowerCore Compact / FireWire have compared to PowerCore PCI / Element?
Answer
Plug-ins running on Firewire-based PowerCores have the same amount of latency as PCI-based PowerCores: the latency is equal to buffer setting of your audio I/O Device."

So I would think the number of samples would be equal to the audio packet buffer size setting. They then go on to say

"Fortunately, most applications have Automatic Plug-In Latency Compensation, so this will not be an issue in mix situations.
When using a Latency sensitive Plug-In in real-time -- such as playing a synth -- you can always switch to No Latency Mode by clicking on the PowerCore button on the plug-in user-interface (see below)."

Metro does support Latency compensation as long as it is a multiple of the audio packet size.

Have you tried the No-Latency-Mode?

Unfortunately we do not have this card in house.

[Paul]

When using the Powercore's zero-latency mode, it's working fine. As far as I know, the UAD card doesn't have such a mode.

The strange thing is that I don't have this latency problem with Logic Pro. I can insert a UAD and a Powercore plugin on the same channel and there's still no latency.

[Jerm]

The strange thing is that I don't have this latency problem with Logic Pro. I can insert a UAD and a Powercore plugin on the same channel and there's still no latency.

Well this is an indication that the problem is within Metro. However it is also possible that Logic does something special to support this card. Without having a card in house it is virtually impossible to debug.

If you can repeat this with a plug-in not running on the card that would be useful. When I get time I will try to contact the manufacturer.

[Paul]

To add injury to insult... ... Live 5 is working OK as well, with both the Powercore and the UAD-card. No latency there...

[Jerm]

My guess is that the latency they are publishing is not a multiple of the packet size. If you reduce the audio-packet size and do the same test with mixing, what is the sample offset?

[Paul]

If you reduce the audio-packet size and do the same test with mixing, what is the sample offset?

I tried this with audio packet sizes 256, 128 and 64 and mixed a track with the UAD Cambridge plugin. With all three packet sizes there was the exact same offset as I mentioned before (2120). Now, I didn't restart Metro after I changed the packet size. Would that be necessary?