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en5ca
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Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
This is quote from revised(?) Logic Pro 10.7 manual. Now the description of PDC compensation for all channel strip types seems to be correct; delaying individual audio streams between nodes (plugins, split points, etc), causing 'extra lag' to maintain sync. Haven't tested 10.7 yet to see if this has been implemented properly. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
That depends on the DAW, and it's 'Low Latency Mode' implementation. Cubase doesn't change the routing, but it bypasses latency inducing plugins from monitored input signal chain to minimize latency while maintaining sync. Ableton and REAPER don't change the routing, they offer the ability to disable PDC for monitored inputs to reduce latency. Studio One and AFAIK Pro Tools bypass plugins and further routing. Logic seems to do all three in Low Latency Mode: bypass plugins, bypass routing and disable PDC in some cases, as shown in ansolas' video. This is perhaps slightly off topic, but regarding to input monitoring the problem with Logic is it does not offer discreet control over PDC while monitoring inputs, and in any case, doesn't properly compensate the monitoring latency to software monitored inputs with or without Low Latency Mode when recording. As shown in ansolas' video, creating the sidechain connection seems to enable PDC on all input monitored tracks without informing the user, or informing that PDC was disabled for monitored inputs in the first place (when in fact it is enabled in the preferences); this should be a global or track preference option, and not depend on the routing. There are some examples on this thread where sidechain PDC isn't working during normal playback in Logic, even after the fix, and when input monitoring is not involved at all. At least Ableton, Cubase and REAPER are able to handle this correctly: maintain sync during playback and recording with software monitoring, compensate recording positions for monitoring latency, and offer user control over whether to use or constrain PDC or not (or bypass plugins/routing) to reduce monitoring latency. What I know to be fixed with Logic is that reordering plugins no longer affects sidechain PDC, and sidechain PDC should work between tracks inside same submix or directly routed to master. What (I think still) should be avoided is sidechaining between different 'layers' or 'depths' of tracks/submixes/buses/groups/stacks/etc when different plugin latencies are involved. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
It would seem without the sidechain connection Logic would operate like Ableton Live does when 'Reduce Latency When Monitoring' is enabled in Live; disabling PDC on monitored input tracks. Although, if you record that, with Logic, you will end up with aligned MIDI notes on different tracks in same non-compensated positions, or aliased reagions, making it impossible to playback like it was heard through monitoring during recording. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
Simple. You don't, at least in sync. But agreed, that probably isn't what they intended, but it's what has been accepted. That's been an issue since early versions of Logic Pro X. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
Unfortunately that seems to be the desired behaviour of Logic when monitoring live inputs through software. Basically making 'record what you hear' impossible with mixed latency input sources. viewtopic.php?f=42&t=152855 -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
According to release notes, nothing has been done. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
"But wait! REAPER has no Low Latency Mode." I hear you say. Well, now there's this free REAPER script extension, which provides such feature for REAPER. ak5k_Low latency monitoring -
Hi! This affects anyone trying to record audio and MIDI at the same time in Logic. Or simply just pays a little closer attention to MIDI recording timings in general.
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Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
It seems the base case of two tracks side-chained to each other has been solved when no bussing is involved, but problems persists with busses and there might even be some new bus related problems too. -
Plug-in Delay Compensation broken with external side-chain
en5ca replied to Holger Lagerfeldt's topic in Bugs & Workarounds
I think that is the unfortunate side effect of the buffering required for PDC to be done properly in case of latency inducing plugins. It takes extra time, memory and CPU power, and usually a relatively large amount. -
My solution was to jump ship, because of this and the neverending automation and PDC problems. Adjusting the audio recording offset on ad hoc basis can work on a very simple setup, but basically requires trial and error approach.
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To sum it up, It seems that the only case when recording timing is correct, is when recording only audio with external zero latency monitoring. MIDI will always get compensated for latency, but not the exact amount, whether it is monitored or not, resulting in offset between MIDI and audio recordings. In fact, any MIDI recordings will always end up with a 'non-correct' amount of compensation. This becomes noticeable with higher latencies and/or when recording audio and MIDI simultaniously. When recording audio through software monitoring, it doesn't get compensated at all.
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Yes. The offset between audio and MIDI recording seems to initially depend on buffer size. With larger buffers the offset is greater. But, if you're working on a lower buffer size, like 64 for example, then plugin latency will play a relatively larger role. If the project has plugins with lookahead function and/or latency. If your buffer is 64, and the project has 2000 samples worth of plugin latency, then the MIDI recording will get compesates to this, but audio recording doesnt. So your sweetspot will probably vary between projects, unless you're always using the same exact template/mixer routing and plugin setup.
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Hi! Unfortunately that does not solve the issue, at least for me, although it can be used as a workaround to some extent in a very simple setup. Indeed that was one of the first things I also ended up trying. The problem is that the offset between audio and MIDI recording seems to depend on the Logic buffer size setting and the total plugin latency of the Logic project, so it practically changes between projects and buffer size settings, and everytime you add/delete/reconfigure mixer with latency inducing plugins. So far I've found it easier to just adjust the recorded tracks manually after recording, than readjusting the recording offset for audio everytime. Another thing is that even though you can get the audio and MIDI aligned with each other in some cases, usually you still can't get them to land on exact beats, meaning in sync with the Logic grid. And practically never when disabling software monitoring from Logic entirely and using external zero latency monitoring. Because Logic seems to always compensate the approximate (I think about 1/2 of buffer + plugins) total latency to MIDI recordings and never compensates audio recordings at all, whether the software monitoring and/or low latency modes are used or not.
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Yes. Just want to point out this technically has nothing to do with the latency itself, but the recording position offset between audio and MIDI. This becomes a problem, if the audio and MIDI sources have direct correlation between them. E.g. set buffer to 1024, load up some fast zero attack sound patch from Jupiter, and record both audio and MIDI from Jupiter. MIDI notes will have ~20 ms offset (if using 44.1 kHz sample rate) in relation to audio. Decrease the buffer size, and the offset will also get smaller. I would expect there to be no offset at any buffer size, and at lower buffer size there technically could be some jitter in MIDI note positions. Although, I don't think this has been a computer or hardware performance issue at least in a decade or something.