Fixing Crackling/Popping when using Sampled Instruments

[ski]

I routinely encounter heavy amounts of crackling/popping sounds when using a combination of EastWest PLAY-based orchestral sounds in conjunction with Kontakt-based orchestral sounds. Now, this generally doesn't occur as I'm creating a new piece of music from scratch (meaning that I'm not using a template, so I'm loading up sounds as I need them, one at a time). But when I recall that project at a later time, playback often results in an incredible amount of sonic artifacts even under light loads/thin orchestration. (BTW, my buffer size = 128).

[ EDIT: to hear an example of this, scroll down a little bit to find my post with the attachment called "crap.mp3" ]

Sometimes the problem gets so bad that the music is unintelligible. In the worst case scenario, playback will go into "slow motion" and what I hear is a smeared stream of semi-musical static. And occasionally this will occur while in the midst of building a new track, contrary to what I said above. Anyway, usually I find that one core is spiking, similar to this screenshot:

Screen shot 2012-06-27 at 9.08.56 PM.png (9.07 KiB) Viewed 440 times

Some of the remedies I've read about included:

- taking any currently record-enabled instrument track out of record (doesn't work here)
- increasing buffer size (not practical, because then I can't play sounds in time)
- creating a new track assigned to "No Output" and selecting it (only seems to work sometimes)

Well, I think I've found a bit of a solution. It's not perfect, but it alleviates these horrible artifacts from being produced during playback:

• Create a new instrument track, but don't load it up with any instrument plug
• Select this track prior to playback

While this won't alleviate crackling/popping during recording new parts, it at least allows for artifact-free playback. As you can see in this screenshot, the CPU distribution has been significantly shifted to two other cores when this track is selected:

Screen shot 2012-06-27 at 9.05.49 PM.png (9.29 KiB) Viewed 440 times

Alternatively, creating an audio track and selecting it (but not record-enabling it) seems to have a similar CPU-load-shifting effect.

[jordito]

Alternatively, creating an audio track and selecting it (but not record-enabling it) seems to have a similar CPU-load-shifting effect.

That's the method I use.

Don't know if you ever read this article:

Logic Pro/Express: Tips for balancing multi-core performance

When a Software Instrument track is selected in the Arrange window, Logic enters "Live Input Mode". In this mode, Logic turns on every plug-in in the channel strip's signal path so the channel strip can be played live from a MIDI controller. All of this must be handled by a single thread and therefore just one core. It's a good idea to keep a track that uses an Audio channel strip selected in the Arrange window, unless you're actively playing or recording to a Software Instrument.

J.

[ski]

Hi Jordito,

Interesting. Guess I'm on the right track then. Thanks for confirming. If only this wasn't a problem at all...

Curious to know if anyone else finds that the problem seems to occur in the same way, i.e., when you're composing, everything's fine. But when you recall the same project, the artifacts start to crop up.

Cheers,

Ski

[jordito]

when you're composing, everything's fine. But when you recall the same project, the artifacts start to crop up.

This I find strange. If an instrument kills my CPU, it kills it anytime, anywhere.

Let's see if other EastWest users can confirm what you're experiencing.

J.

[ski]

Just to give you an idea of what I'm dealing with here, I've attached a very short snippet of a piece I'm sketching out using a combination of E/W Play and Kontakt plugins. (Don't expect any kind of realism or audio quality, it's just a sketch). More importantly, you'll hear the kind of crackling that I'm dealing with with an instrument track is selected. Jordito and others, does the noise you hear in the recording sound at all familiar? Anyone else get this?

For now I'm going to move everything over to VEP which usually doesn't give me this kind of problem. GAH!

Cheers,

Ski

[BJG]

I've been having the same problems with EWQL. I solved a lot of it by starting to run it in stand-alone, and jacking the CPU limit up to 90% in the Play Engine. For some reason that keeps Play and Logic happy, both being able to inefficiently hog their own territory in CPU land.

I've also just had terrible issues with the EWQL plug-in inside Logic; strange gremlins causing strange things, like an entirely random note/sample being played back all out of time! I've plenty of memory, and a dedicated drive for the sample library that works just wonderfully in stand-alone.

My Macbook model is a two core i7 with hyper-threading. I'm not seeing any benefit from switching Logic's threads from automatic, 2, or 4. It's always stuck on one core, regardless of moving plug-ins across auxes or the empty - No I/O audio track tip.


Logic is definitely due for a massive CPU engine overhaul, I second that it really is a shame it's a problem in the first place. Part of me, through reading clues here and there over the years, is starting to theorize and point the blame at the AU format itself being flawed.

-B

(Also I should add that I'm never really using more than 16 instruments in EWQL, so in your case Ski I feel your pain!)

[ski]

BJG, thank you SO much for your reply. (And Jordito too, of course!)

Right now I'm taking an inventory of what I'm using at the moment in the project so that I can xfer those plugs to VEP. Though now that I've read your post I'll experiment with setting the CPU to 90% and seeing if that improves things within Logic itself. I'll also see if I've got more than 16 Play plugs happening.

To your experience with the random, notes-played-out-of-time thing, I've only had that happen once with an MOR drum kit, but thankfully not more frequently. When it was happening it was driving me batty, tho, so I definitely feel your pain too.

Thanks again,

Ski

[BJG]

To your experience with the random, notes-played-out-of-time thing, I've only had that happen once with an MOR drum kit, but thankfully not more frequently. When it was happening it was driving me batty, tho, so I definitely feel your pain too.

It was ridiculous; I would have to try and "freeze" a track multiple times in order to win the "it plays back in time" lottery! Just never got Play to work as an AU plug-in in Logic without it being a random crapshoot. Ever since I switched to stand-alone, it's been absolutely trouble free with nice and low buffer settings in Play and Logic. I almost prefer just being able to "tab" over to it compared to say, having a Screenset for it.

Again, I think a lot of this is stemming to an AU issue all around. Are you switching to VST format when hosting in VEP? I've never gotten desperate enough to seriously look at that because as I said, one instance of Play in stand-alone with 16 channels is more than enough for the stuff I'm doing with it (Orchestral stuff for pop music), and the Soundflower route works just peachy!

I'm noticing that a lot of developers are struggling in general with the AU format, especially when it comes to plug-ins that deal with MIDI. I wonder if Digital Performer users, or Ableton Users, that have the option to choose the AU format, are experiencing very similar issues?

-B

[ski]

Thanks again for your reply BJG.

VST format for Play... I'm not even sure I have those on my system so I'll have a look. I take it there's a CPU reduction when using VST's instead of AU?

Most of the other composers I know are using Logic, and one in particular suggested that I not mix Play and Kontakt in the same project. Something about how their memory servers conflict (don't quote me on that tho). Of course, using VEP can help separate church and state, as it were, but when I'm sketching ideas for difficult music as I'm writing now, I want to take the easiest route and load up the sounds I know will work right in Logic. That's proving to be an exercise in futility, though. Anyway, enough bitching from me.

When you say that developers are struggling with the AU format, I'm curious to know in what way. Is it that the ever-increasing demands they put into the plugins for scripting and sheer number of samples is overwhelming the AU format capacity to actually play back this stuff in the first place (he asked, concluding with an incredulous, if not slightly nervous "LOL")?

=sKi=

[BJG]

It's just a general "hunch" I'm getting from reading clues here and there over the years. I'm no programmer, but I'm seeing a pattern and curious if my train of thought has an validity. Not to be taken too seriously!

Some evidence gathering;

The attempted Massey exodus from RTAS to AU a few years ago was a fairly public cry about Apple and the AU format, enough for him to give up the project. I believe there was an "open letter" about the matter if I remember correctly.

MIDI plug-ins that have surfaced the last few years, such as Xfer's LFO-Tool, and Cableguys Midishaper, are not fully functional in the AU format. This is were I first learned that the AU format cannot "send MIDI" without some mass wizardry.

And when it does...

Then came the plug-in version of Numerology, which was a hot, hot mess at first from what I've read. Jim, the genius behind that program, is pretty candid and open about problems that arise to the Numerology community.

To balance out CPU issues with Logic, I'm hosting some VST counterparts now inside of Bidule. (thanks to your help in getting my environment all spiffy!) Plug-ins like those from FXpansion, run much better in the VST format. Tremor, Fxpansions drum synth, is a real CPU hog; and it is quick to have it's track frozen in Logic. However, I seem to be able to just keep it open and run multiple instances when hosting it in Bidule and just pointing an external track in Logic at them. It's not the same performance if I host the AU version in Bidule. (Bidule can host AU and VST at the same time)

It's just kind of making me think it's not just Logic's engine to blame entirely on some of these quirks, but possibly just the AU version having the potential of being more "buggy" because it was just that much harder for the developer to implement it. I'd love to run into a Digital Performer user and pick their brain to see if there are similarities with problems. I worked on a record last year where one of the other prodcuers was a DP user; wish this was on my mind then! I would love to find the definitive word on the subject!

-B

[jordito]

MIDI plug-ins that have surfaced the last few years, such as Xfer's LFO-Tool, and Cableguys Midishaper, are not fully functional in the AU format. This is were I first learned that the AU format cannot "send MIDI" without some mass wizardry.

Don't know about Midishaper, but the new version of LFOTool can output MIDI to an IAC bus.

Usually developers go the IAC route and/or do it via virtual MIDI ports.

By the way, Audio Units support MIDI output since 2007. The problem is hosts like Logic don't support it:

http://lists.apple.com/archives/Coreaudio-api/2007/Mar/msg00053.html

J.