Delay compensation and latency

[Propellerhands]

Again me. Have a few questions and how to approach the problem that I am having.

Today I noticed that on a track that I am working my drums are lagging behind while playing (merely 10 tracks). Then looked at the bottom of Reason and noticed that Delay Compensation is lit up and number 8 below it. When hovered over with a mouse it said 0.2 ms latency. And this lag does not happen everytime, but around 5 times out 10, so if I stop the track and play again, it sometimes sounds ok. For a while. CPU usage is barely 45-60 percent at chorus.

Could this be related? Provided I have two instances with Iris 2 so I thought, maybe it was infamous Iris which was causing latency?
I bounced one instance of Iris 2 in place and still no effect or barely.

Well, then I started removing devices one by one to see when will delay compensation go to to 0 value and found out that the cause were two plugins.

OTT on a kick drum (total of 2 sample latency by default no matter the preset)
And certain FapFilter Saturn 2 presets. In my situation it was 6 sample latency. So overall 8.
Then I scrolled through other presets in Saturn and found one with 3212 sample latency? What's up with that? Preset had linear phase enabled there and high quality too.

If someone could explain it in layman's terms would be awesome. For now I think I will just use some other saturator instead of saturn.

[jam-s]

Any plugin that needs to "peek into the future" for its algorithm will introduce latency if it correctly reports that latency to the host (=Reason) and delay compensation is turned on, then all other tracks are delayed in time to keep everything in sync as timetravel tech is not (yet?) available in this universe according to Einstein.

[Propellerhands]

Any plugin that needs to "peek into the future" for its algorithm will introduce latency if it correctly reports that latency to the host (=Reason) and delay compensation is turned on, then all other tracks are delayed in time to keep everything in sync as timetravel tech is not (yet?) available in this universe according to Einstein.

Ok then, how do you explain the latency of 0.2 ms then? Or the fact that my drums are lagging behind? Perhaps the issue is somewhere else, not in specific plugins causing Delay Compensation in Reason? Again, it does not happen everytime, just occasionaly while I am still mixing my song and not a single track is bounced (because Reason handles this stuff very inconveniently, compared to say, Ableton)

[jam-s]

Without info on your project sample rate and the "use audio device buffer for rendering" setting this is pertty much just wild guessing, but 0.2 ms could be just the few samples delay that is introduced by the plugins or delay compensation
8 samples @ 44.1kHz = 0,00018 s (~0.2 ms).

Also have a read of the relevant sections of the fine manual: (1) (2) (3).

[Propellerhands]

Without info on your project sample rate and the "use audio device buffer for rendering" setting this is pertty much just wild guessing, but 0.2 ms could be just the few samples delay that is introduced by the plugins or delay compensation
8 samples @ 44.1kHz = 0,00018 s (~0.2 ms).

Also have a read of the relevant sections of the fine manual: (1) (2) (3).

I use stock settings, 44.1kHz with 256 buffer, audio card Scarlett 4i4, multicore, hyperthreading enabled. But basically what I just wanted to know would 0.2 ms latency affect my drums so much?

And thanks for pointing me to relevant info! Had no idea of this feature in Reason (“Show CPU Load for Devices” from the Options menu.) I think I found plugins causing the most issues so will try replacing them or just keep an eye next time.

[friday]

From my perspective 0.2ms is a to small amount to hear something lagging. Therefore, I suspect that it is something else to blame. What happens if you deactivate the Delay Compensation?

[Propellerhands]

From my perspective 0.2ms is a to small amount to hear something lagging. Therefore, I suspect that it is something else to blame. What happens if you deactivate the Delay Compensation?

You are right, it was something else. Also no effect when disabled Delay Compensation. I noticed disabling one instance of Iris 2 removes about 25% of my CPU load. Anyway, I played a bit with my buffer sizes, decreasing it to 64 (got no clicks or anything, just CPU usage went to 70%) then increased it to 1024 and it removed CPU load from 60 to 40 percent, so most likely it was my buffer size.

[jam-s]

I use stock settings, 44.1kHz with 256 buffer, audio card Scarlett 4i4, multicore, hyperthreading enabled. But basically what I just wanted to know would 0.2 ms latency affect my drums so much?

And thanks for pointing me to relevant info! Had no idea of this feature in Reason (“Show CPU Load for Devices” from the Options menu.) I think I found plugins causing the most issues so will try replacing them or just keep an eye next time.

You're welcome. Hyper-threading can also have negative effects on performance for audio processing. try if disabling it helps to improve performance and also make sure the power settings are set to high performance, as dynamic clocking of the CPU cores can really mess with real-time audio processing at low buffer settings.