How to find the cause of dropouts

[jkoseattle]

I get it. dropouts of the audio engine have to do with processing at runtime, so increasing buffer size, reducing effects, etc are all remedies to improve it. But how do I know which?

This project has a couple dozen instruments with some effects on some of them. I keep getting dropouts in the same places. Specifically today, it's at a part where only about 5 instruments are even playing, yet this quiet little part drops out EVERY F___ING TIME. I try turning off effects - still drops out. Try pre-loading all instruments that are playing at that time. RAM usage goes way up, but dropouts still happen. 

I'm shooting in the dark here. I don't know WHY a dropout ever happens. It's like CW just says "Sorry, nope", and if I want it fixed, well that's my problem. But I have nothing to go on.

5 instruments playing

FX disabled

Buffer size maxed out

Drops out every time. WHY??? Is there any way to narrow it down and find the culprit or do I just try stuff (and eventually give up and move on)?

[reginaldStjohn]

This sounds more like a problem with the project right at that point. Dropouts due to CPU load tend to be more random and not in the same place all the time.

Do some experiments like, enable ripple edit and move everything down the timeline a good 10 measures or so. Does it still drop out at the same time or at the same place in the music?

Save a copy of your project to a new location, make sure to check copy project audio. Does it still happen in that newly saved project? If it does, start removing tracks one at a time to see if you can narrow down what might be causing it other then effects.

I know this can be frustrating. Computers and software can be complicate things.

Edited July 13 by reginaldStjohn

[Noel Borthwick]

1 hour ago, jkoseattle said:

I get it. dropouts of the audio engine have to do with processing at runtime, so increasing buffer size, reducing effects, etc are all remedies to improve it. But how do I know which?

This project has a couple dozen instruments with some effects on some of them. I keep getting dropouts in the same places. Specifically today, it's at a part where only about 5 instruments are even playing, yet this quiet little part drops out EVERY F___ING TIME. I try turning off effects - still drops out. Try pre-loading all instruments that are playing at that time. RAM usage goes way up, but dropouts still happen. 

I'm shooting in the dark here. I don't know WHY a dropout ever happens. It's like CW just says "Sorry, nope", and if I want it fixed, well that's my problem. But I have nothing to go on.

5 instruments playing

FX disabled

Buffer size maxed out

Drops out every time. WHY??? Is there any way to narrow it down and find the culprit or do I just try stuff (and eventually give up and move on)?

What is the dropout error code shown? I added those specifically to aid in diagnosing drop outs.

To rule out something at the point of failure, try starting playback a measure or two before that point. If it plays past that and drops out elsewhere later then the problem is cumulative. The error code is the best way to diagnose further in that case.

[jkoseattle]

Hmm, both interesting answers. To both, as it turned out, I ended up deciding I didn't want two of the instruments in there musically, and as soon as I deleted those clips, it stopped always dropping out. Those two clips were tremolo strings and tremolo cellos.

@reginaldStjohn When I moved the music out 10 bars, it still stops at the same place in the music, not the same place in the project. Copying a new version of the project to test would have been a good idea, and I'll remember that for next time. So on one hand I can understand that tremolos consist of a whole lot of fast notes, but I guess I assumed it was just a single piece of audio rather than each individual note in the tremolo being it's own thing. But apparently not. What's weird is that I suspected as much before I removed them, so I pre-loaded the entire patches, which added a Gb or 2 to my RAM footprint, but I had plenty of headroom so it was ok. But even pre-loading didn't help. Which I don't understand at all. Doesn't that pre-load all the audio into RAM so it doesn't have to fetch off the SSD? I guess I don't understand it. 

@Noel Borthwick It was always error code (1). Where do I look those up? The problem is not cumulative, because I was specifically just playing a short section when the dropouts were happening. 

[Noel Borthwick]

13 hours ago, jkoseattle said:

Hmm, both interesting answers. To both, as it turned out, I ended up deciding I didn't want two of the instruments in there musically, and as soon as I deleted those clips, it stopped always dropping out. Those two clips were tremolo strings and tremolo cellos.

@Noel Borthwick It was always error code (1). Where do I look those up? The problem is not cumulative, because I was specifically just playing a short section when the dropouts were happening. 

The dropout reason codes are all documented in the help.
https://legacy.cakewalk.com/Documentation?product=CakewalkSonar&language=3&help=AudioPerformance.24.html

code 1:

Audio processing took longer than the buffers allotted time slice.

Increase the Buffer Size value in Edit > Preferences > Audio - Driver Settings.

The recommended action just a general suggestion. It would appear from your symptoms that the synth is taking a huge amount of time to process the string tremolos. If it takes longer than the quantum of time determined by the audio buffer size for N consecutive buffers the engine will trigger a dropout and stop playback.

You could bounce that section to avoid this issue. Have you tried running the same project on a different machine if you have one?
Its also possible that there is something else that leads to the problem, eg a fragmented disk. Perhaps the synth is trying to do disk I/O and its simply too slow to keep up.

If you can send a trimmed down project with just the section in question that drops out I could take a look and see if there is anything else that jumps out.

 

PS: depending on the number of cores you have enabling plug-in load balancing may also help with this.

I would also contact the plug-in vendor to ask why the processing is so expensive and if it can be optimized.