Playback problem with VSL Synchron Prime on Dorico 4

I use the latest version of Dorico 4 on a Mac mini with M1 processor and 16 GB of ram on Mac OS 12.3 Monterey. I downloaded a 30-day demo of VSL Synchron Prime in the hope its comparatively modest computer requirements would allow it to function smoothly but found it plays back my test piece the first time with annoying pops and clicks but afterwards, plays back smoothly. This behavior is unchanged regardless of the number of initial samples I load into the Synchron player. VSL has been very helpful and tell me this problem does’t arise on similarly spec’d Windows computers and, in any event, I should get noticeably fewer pops and clicks as I load more initial samples into the Synchron player. VSL suggests the problem doesn’t appear to be based on the 16 GB ram on my system but instead from a software hangup from either Dorico 4 or the Monterey operating system. Has anybody else tried Synchron Prime with an M1 processor and have you had similar problems?

I note with interest Daniel’s response 2 weeks ago in the thread “Why does Dorico work so hard when changing instrument routing?”:
An update on this issue: we have isolated the things that Dorico 4 is doing differently than Dorico 3.5 in this regard, and in an initial test with BBC SO we have got the response time down to more or less the same as Dorico 3.5. The change will have to go through testing and so on, but there’s reason for optimism that this should be resolved in the next update.

The next update came out today and I wonder if the changes referred to might also resolve the problems I was having with the first playback of Dorico files when using VSL Synchron Prime. Unfortunately, my demo copy of that library expired a couple of days ago so I am unable to try out the updated version of Dorico 4 and see for myself. The problems I experienced also showed up in a playback of my test file by “Andreas” at VSL who was very helpful throughout and came to the conclusion:

I can confirm the issue with requiring a 2nd playthrough - but only on Mac, for some reason. I wonder if that is some strange interaction with Dorico on Mac… I just checked with a huge preload size 32768 and the same issues can be experienced for the 1st play through. And that was 12 GB already loaded - instead of 1 GB. So it’s not a player streaming issue.

EDIT: I want to add something about the Dorico file I used for testing and I hope this edit won’t bump my post. Following John Barron’s March 31st “Discover Dorico” session, I entered the first 14 bars of Mahler #1, mov’t. 4 and this was the primary Dorico test file I used with Synchron Prime at home and sent to VSL. I mention this to clarify that my playback difficulties were not related to huge numbers of instruments or bars. IRV was turned on to accommodate condensing.

@dspreadbury, I hope the conclusion of my first posting above doesn’t obscure the fact that I’m hoping to learn whether my playback problems might arise from an unusual Dorico problem with Mac as the VSL employee suggested might be the case—apologies if you are already looking into this!

Hi @Mike_999 , clicks and pops during playback usually mean a problem in the audio engine, and not that Dorico can’t stream quick enough the MIDI data to the audio engine. So I don’t think that it has anything to do with Dorico as such, especially not with the problem Daniel mentioned.
Well, I can get in touch with Vienna and ask them for a Prime license and try it out myself, I have an M1 Mac Mini here as well.

Thanks, Ulf! I’m hoping the problem can be resolved without (eventually) moving to a more powerful computer. This seems likely, though, since VSL says the problem doesn’t arise on a similarly spec’d Windows machine and the M1-equipped computers account for themselves very well in most respects.

Btw, would you be able to share your test piece with me, @Mike_999 ?

The attached file was the first one I played back using VSL Prime and also the one I sent to VSL (my communications there were with “Andreas”). Also, my M1 Mac mini is the one with 16 GB of ram.

2022-06-03 23-39-32_Mahler.Symphony 1.Movement 4.vsl.dorico (1.6 MB)

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Hi @Mike_999 ,
I have now Synchron Prime running on my Mac and can confirm that behaviour.
However, I think the problem is on Vienna side.

I also tried with a new audio engine that is more close to the latest Cubase 12 audio engine and which has a lot of improvements, especially for running on Mac, but the behaviour is always the same.

The fact that it only happens only during the first time playback after project load, makes me think it is not our fault. Even if I load the project and wait for a couple of minutes before starting playback, I still get the audio drop outs. Our audio engine runs stateless and knows nothing about project start or first time loading, it just sits there processing whatever is currently in that moment needed.
From a different case I also know, that the Synchron Player easily reaches the limit of the CPU, because it is not optimized for multi-core processing. I had a user with a very powerful machine and lots of cores, but Synchron player would only ever make use of one core. Then this one core would be completely stretched out and drop outs occured even though 15 other cores had basically nothing to do. Something along this effect also takes place here, I think. Probably the fetching of samples is the culprit. Synchron only preloads a certain amount of samples and needs to suddenly load other stuff when the playback starts. Once it’s running everything is there and playback is smooth afterwards.
I will try to get in touch with VSL developers and discuss this further .