Channels lagging


I usually record my band live, drums, bass guitar, keyboards, up to sixteen tracks total. About a year ago my keyboard player got his “Leslie” cabinet fixed and this strange problem occurred.

All though I know his playing is ok, when we listen back the Leslie tracks are lagging here and there. I tried moving the Leslie mic’s from my Behringer ADDA converter to my Focusrite Scarlett, but that didn’t help.

I’ve tried all kinds of settings and some are better, but nothing gets rid of the problem completely.

Today when I did a quick mix of our practice session I thought the channel switching had worked, but when I started turning my plugins on (CLA drums) the Leslie channels started lagging.

Any suggestions?

My system: Lenovo Thinkpad laptop, 64, it 4 Core.
Magix Samplitude Pro XR DAW.

Cheers, Mikael

I’m not on my audio PC at the moment so I can’t measure CLA Drums myself — but the latency added by plugins is almost always related to PDC. Plugin Delay Compensation.

It’s a feature - not a bug… But plugins that add a lot of delay are usually intended for mixing – not tracking or composition… Because they introduce delay.

One such example is AR TG Mastering Chain. It has quite a bit of latency… But they also have a “Live” version which uses different processing to avoid the latency.

It’s useful to know the PDC amount of your plugins. In Reaper, there is a “Performance” tab which lets you see.

PDC works in parallel across multiple tracks, but it adds up in series cumulatively on a single track.

For example, you could use a plugin with 64 samples of PDC across all your tracks and your total latency would just be increased by 64.

However, if on one of those channels you used four instances of that plugin your latency would add up to 256.

Your PDC latency is based on the highest total track latency + whatever submixes and master bus effects it passes through.

To give another real world example, lets say you used J37 – the tape plugin – on your track. It’s around 108 samples of PDC latency. If you then used it on the submix, and the master bus — that would add up to 324 samples of PDC. You can feel that.

For this reason, I use plugins with low or no latency during tracking/composition… Scheps Omni Channel, for example, is incredible because it’s low-CPU and zero latency. (EV2 is great, too, but it does add ~56 or ~64 samples of PDC latency (I forgot the exact amount.))

Your ASIO buffer size also plays an enormous role in latency, but surely you know that. Try to keep that as low as you can during tracking. I usually work at 96 or 128… During mixing I will sometimes have to bump up to 512 if I am using 100+ VSTs, etc.