Digital Audio Workstation & MIDI > Digital Audio Workstations & MIDI Applications

Audio recording precision

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gert79:
I will try again without the monitoring (thru), maybe that improves it.

gert79:
I removed the loop and draw the notes over 8 bars, also i disabled "thru" direct monitoring in SVP and used the soundcard monitoring.

I tried all kinds of buffer settings, with and without process ahead, largest buffer, smallest buffer, medium settings.

For now i turned off "process ahead" and defined an offset for recording, 2x256k recording buffer, 64 samples ASIO buffer.

I really made a lot of recordings in SVP, the multiple takes look "quite good" with some deviations.
However if i load the aiff files to a wave editor and compare the earliest played and last played note at the beginning (4th note on) of the recording i have a 2.64 mS deviation, in the end of the recording (1st note on last bar) 2.42 mS.

I don´t know how much precision is even possible here (to me personally less than 0.5mS always would be nice), i already had these issues on my windows DAW but back then i could not figure out if it is midi jitter or issue with recording.

In my understanding it is the same signal and should be aligned in the same way always?

IIO:
as others have correctly pointed out, delay and the length of the delay can depend on many things, which one would have to know.

and you can not expect perfect synchronisation between a track played live via midi and the recording of it.
and normally this should not be a big deal, because you would just measure the delay and predelay the audio and or midi tracks, be it while recording, be it later when everything went audio.

the main issue here seems to be that the delay is different every time. this should not happen and is probably not related to the program used.

GaryN:
AAARRRGH!!! I typed out this entire thing and it all somehow vaporized when I previewed it!!!

Calming down…… Repeat to oneself: "I SHALL save to a text editor regularly when pontificating on the Forum"……… OK
OK…  This is where the AHA!! goes→ → → → → AHA!!    Things quickly become clear when you know what you're looking at.

You are not seeing "jitter". You're seeing audio latency.

It's the sum of all of the processes that generated the results, both MIDI and audio. The good thing is that it's correctable.
You hacked on every adjustment you could find but you missed: Play and Record Offsets

All digital audio systems have latency both when recording and when playing back (but you already know that (?)). Some, more than others. Our 20-odd-year-old ones certainly have a fair amount compared to today's stuff. Opcode realized this immediately when they tried to run early versions of SVP on barely–PPC powered Macs and the MIDI and audio wouldn't sync.

The consistent "lagging behind" of the audio relative to the MIDI "notes" in your display is the clue – the additional lag on tracks 4 and 5 in the second shot are possibly due to something you did differently.

I have a narrow perspective on "jitter". From early Sequencer on my Mac Plus, thru using Vision for MIDI while syncing audio on my 8-track R2R, to being positively thrilled with StudioVision adding real DAW functions… I have never had an issue with it…period. Nor do I know any other SVP users who do. The Opcode MIDI System was developed to both integrate all of the users MIDI devices with the sequencer (before audio) and also to maintain accurate MIDI data timing. Everybody I've ever heard complain about "jitter" has had that issue with other software (and especially PC software)…or more often mistaken MIDI "clog" and such from an inadequately setup system, MIDI–over–USB with inadequate MIDI clocking and too much other shit on the USB bus or just plain too much unnecessary controller data and the like.

I'm not saying there's absolutely no such thing as jitter. MIDI has a finite resolution and hardware has limitations that can and do cause inaccuracies. What I am saying is it gets a lot more culpability than it deserves and a properly setup system shouldn't have an unacceptable, audible amount of it.

Anyway, this is addressed in the SVP Audio Manual Part 3, Chapter 11: "Acadia: Optimizing for Digital Audio"
Give this stuff a try and run your test again. See if you get acceptable results.

I've attached the relevant pages here just in case.

IIO:
i think so, too. he probably changed some settings when trying again.

so he should repeat testing it for another two rounds.

once it is always the same amount of shift, it can easily be corrected.

even to find out which settings are responsible (so that one might change them) requires to first do a correct measure.

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