Synth latency

[jonahmo]

I've been developing a Live set on my Macbook Pro, which performs fine, but now that I'm trying to use VJ software, VDMX5, with it I'm getting some issues. When I stack enough effects plug-ins onto VDMX5 and I'm trying to play a Live synth, I'm experiencing some erratic latency of the synth notes that I'm playing.

While this is happening I look at Activity Monitor and it appears totally normal - nothing is near maxing out. The synths, specifically Operator's FM Koto and Simpler's Soover, have these issues, however I can rapidfire 30 different audio clips with a ton of plug-ins and have no issues at all.

One thing that might be worth noting, I'm running Ableton and the OS on one partition, and the media files are stored on the other partition. Also I'm sending MIDI data to VDMX5 via several of Max For Live's Livegrabber plugins.

I've already increased my audio buffer and decreased my in/out sample rate as far as I'm willing to go. I hope that I don't need to resort to using an external drive to store my media files.

Running a 2.5 GHz Intel core i7 processor, SSD, 16GB of 1600MHz DDR3 on a mid 2014 macbook pro, OSX 10.10.something.

Any suggestions would be much appreciated. Thanks.

[wearemindflux]

Hi, I would check your buffer size.

When working with inputs you want lower buffer size and if there is still delays you can use the external instrument in Live to sort that. Or even the track delays.

[Stromkraft]

Or even the track delays.

That's not, I repeat not, what the track delay does.

[fishmonkey]

if latency is a problem, then raising your buffer size and lowering your sample rate are exactly the opposite of what you want to do. both actions reduce CPU usage, at the cost of increased latency.

in contrast, lowering your buffer size and/or increasing your sample rate make your computer work harder to process audio more quickly and in smaller chunks.

from memory, in Live, MIDI buffering is also affected by the audio buffer size (but i might be mis-remembering that).

https://help.ableton.com/hc/en-us/artic ... ce-latency

also, the stock Activity Monitor is not sensitive enough to diagnose the kind of processing spikes that can cause audio issues. are you getting any audio glitches, or is it problem purely that the synth triggering is delayed?

[jonahmo]

if latency is a problem, then raising your buffer size and lowering your sample rate are exactly the opposite of what you want to do. both actions reduce CPU usage, at the cost of increased latency.

in contrast, lowering your buffer size and/or increasing your sample rate make your computer work harder to process audio more quickly and in smaller chunks.

from memory, in Live, MIDI buffering is also affected by the audio buffer size (but i might be mis-remembering that).

https://help.ableton.com/hc/en-us/artic ... ce-latency

also, the stock Activity Monitor is not sensitive enough to diagnose the kind of processing spikes that can cause audio issues. are you getting any audio glitches, or is it problem purely that the synth triggering is delayed?

Thank you. I understand the buffer/sample rate concepts, but it's not normal/consistent latency. It's erratic, in that I can hit a note over and over and sometimes it plays on time, sometimes it's delayed up to almost a second. And no, there are no other audio glitches - only the synth triggering.

[Stromkraft]

Thank you. I understand the buffer/sample rate concepts, but it's not normal/consistent latency. It's erratic, in that I can hit a note over and over and sometimes it plays on time, sometimes it's delayed up to almost a second. And no, there are no other audio glitches - only the synth triggering.

That sounds to me that the CPU is working hard at shorter periods, even postponing events. Which I've seen a few times, like two or three in 6 years. Is the machine responsive otherwise when this happens? In my case, it wasn't.

[wearemindflux]

Or even the track delays.

That's not, I repeat not, what the track delay does.

I am meaning more for monitoring. Also with reduce latency while monitoring can help.

[Stromkraft]

Or even the track delays.

That's not, I repeat not, what the track delay does.

I am meaning more for monitoring. Also with reduce latency while monitoring can help.

I'm not following you here unfortunately. My point was that Track Delay always adds latency.

[wearemindflux]

Not when using a minus value

[Stromkraft]

Not when using a minus value

Especially then. Because there can be no events taking place before 1.1.1. So all other tracks are delayed! OK? Think about and then make some tests. Since I did I abandoned Track Delay.

You're likely thinking about hardware latency adjustment, like in External Instrument. That's something else.

[jonahmo]

Not when using a minus value

Especially then. Because there can be no events taking place before 1.1.1. So all other tracks are delayed! OK? Think about and then make some tests. Since I did I abandoned Track Delay.

You're likely thinking about hardware latency adjustment, like in External Instrument. That's something else.

In any case, I need my monitoring to have very little latency, so I can hit notes on time.

To answer the previous question, when I'm experiencing the delayed MIDI notes everything else seems to be running normally, except if I'm trying to drag a finder or app window across the screen it's slow/choppy. I think the video output is also choppy at these times, but I haven't been watching it very closely so I don't know for sure. A Mac expert friend said that it seemed like there was a MIDI bottleneck, possibly due to multiple apps trying to do MIDI stuff at the same time. Not sure what I can do with that info though. It could also have something to do with running the app, Junxion, at the same time I guess? I'm at a loss.

[[jur]]

Try without Junxion?

[Stromkraft]

In any case, I need my monitoring to have very little latency, so I can hit notes on time.

Which is why you need to remove all sources of latency one by one. You certainly don't want to add new ones for no obvious benefit.

To answer the previous question, when I'm experiencing the delayed MIDI notes everything else seems to be running normally, except if I'm trying to drag a finder or app window across the screen it's slow/choppy.

How often do you need to do this? I thought you were playing and not dragging things around.

Why haven't you already tried to isolate these issues? You must start with the minimum, everything else taken out of the MIDI path, and check that this base setup works fine. Also check every device for its latency.

Don't change the base once you know it's working. Then you add one thing and evaluate the same. Only then add something else. This way you have a chance to discover what's behind these issues for you. It certainly could be some kind of overload, but that doesn't have to be it.

When you use this Junxion app what MIDI source goes into it?

[wearemindflux]

Not when using a minus value

Especially then. Because there can be no events taking place before 1.1.1. So all other tracks are delayed! OK? Think about and then make some tests. Since I did I abandoned Track Delay.

You're likely thinking about hardware latency adjustment, like in External Instrument. That's something else.

I will give it ago but never had a problem, I did mention the external instrument so no not thinking of that

[jonahmo]

Quitting Junxion has no noticeable effect. Changing the buffer/sampling rate has no noticeable effect. The erratic MIDI latency also seems to coincide with choppy video output. Removing video effect plug-ins solves the problem. But I need those effects. VDMX is barely doing anything - just running some basic effects on three still images. And Ableton is barely using any plug-ins or doing anything besides having a single MIDI synth played live, running one track of audio, and sending OSC data to VDMX (via several of Max For Live's Livegrabber plug-ins). It seems like my computer should be able to handle this. And to answer the question about moving windows around, it's not something I'll need to do while I'm playing Live, just another symptom I noticed so I thought it was worth mentioning.