Crackling audio in REAPER

[More Sound]

Smart people - I need your help. I am experiencing crackling audio at high CPU usage. Here's an overview of my specs:

- latest version of REAPER on Windows 10
- RME Fireface UFX II (latest drivers)
- 32GB ram, 4ghz i7 CPU, all SSDs
- 512 ASIO buffer size

I am posting here because I feel like I've tried every possible setting, to no avail. Changing "Buffering" settings does help, and the best settings I've found are as follows:

Thread priority: Time Critical, Behavior: 15 - Very Aggressive
Media buffer size: 4800, prebuffer 100%

I am running a very taxing session. It's 88.2khz, with plenty of tracks and plugins. REAPER reports my CPU usage as between 70-85%

Of course, I understand there are limitations to what I can ask of my system. However, I am working with very detailed material, and I cannot have ANY crackling. It makes it impossible to listen for crossfade errors, or clicks, for example. This crackling continues even in solo mode (presumably because the rest of the tracks are still being processed, just not audibly).

I'd rather have the audio drop out, get a CPU "over" error message, experience stutters, ANYTHING other than this crackle. It's making it extremely difficult to work on this material. I'm a recent convert from Samplitude, and in that program, it's clean as a whistle, up until a CPU-overload threshold, and then the audio drops out and the program freezes up a bit. With REAPER, the crackle seems to begin around 50%-60% CPU and gets worse and worse as the demand on the CPU increases.

I'm happy to try anything. Because the system is so reliable under Samplitude (and has been for 4 years), and my RME drivers are legendarily stable, I have to assume this is a REAPER configuration thing.

Thanks in advance. I love REAPER so much and I want to stay with it.

[mschnell]

With more than 80 % CPU, some amount of crackling supposedly cant be avoided.
Tweaking the Computer system for more realtime compatibility might help, though.

-Michael

[BrentHarmon]

Have you try different block size to see the crackling goes away?

[More Sound]

Are you talking about Preferences/Audio/Device where there is a "Request block size" check mark and input field? Yes, I have tried all sorts of combinations here.

Truly, no amount of crackle is acceptable. I am editing sophisticated material and it will drive me nuts to wonder if I'm hearing little glitches or actual problems with the audio..

[mschnell]

If you bdon't want to use workarounds (like freezing tracks and/or using pre-rendered subprojects), maybe a CPU with a lot more cores might be necessary...
-Michael

[More Sound]

I have a great CPU. I don't have crackling issues in Samplitude. I have other issues, which I won't bore you with. But a stop, pause in audio, warning message on the screen, etc are all far more preferable to me than what sounds like crackling that starts very subtly and increases as the CPU usage does

[masapasa]

Hi! I had same kind of issues. Is audio crackling when you move a mouse? Try to enable ”mouse trails” on windows mouse preferences. It’s weird but it helped with my computer (i9 and rme UFX+).

Mouse pointer changes when you move it over audio files and different parts of arrange window. For some reason it causes crackling and glitches.

[More Sound]

That's fascinating. I don't think it's associated with my mouse movement but it won't hurt to give it a try.

I just tried disabling Hyperthreading in the BIOS, and an initial test seemed to show good results. That's in line with my suspicion that this is a BIOS issue rather than a Reaper configuration thing per se.

But, I'm still welcoming any ideas on this. I am really excited to fully adopt Reaper and this is one of the very few little snags.

[mschnell]

In the sticky thread in the "Live" subforum there is a list ow links to articles on tweaking Windows for realtime performance.

-Michael

[More Sound]

That's great, thanks!

I've been doing some experimentation and I've found that REAPER seems to exhibit less cracking when I disable Hyperthreading in BIOS. Ironically, Samplitude seems to work better when I *enable* Hyperthreading.

Has anyone reading this noticed any particular trends in terms of Hyperthreading and other BIOS settings?

[mschnell]

Technically, the influence of Hyperthreading in realtime performance is extremely complex and unpredictable.

-Michael

[ivansc]

Just in case... you ARE using the RME ASIO drivers for your interface, I presume?

If so, it is the ASIO buffer that will help you overcome this issue, not the ones you have been adjusting.
Go into Audio Device & pull down the list of devices. Select ASIO & your device, then click on the ASIO settings button and adjust the buffer size there.
I usually run my RME HDSP 9652 at 32 or 64 buffer when recording then increase it to 512 for mixing.
This is on a very old 4 series i7 cpu with 16gb of memory running win 10 pro 64.

[dug dog]

I don't have that interface, so no direct experience, but I wouldn't hesitate to experiment with setting the ASIO buffer to 1024.

[serr]

Originally Posted by More Sound

That's great, thanks!

I've been doing some experimentation and I've found that REAPER seems to exhibit less cracking when I disable Hyperthreading in BIOS. Ironically, Samplitude seems to work better when I *enable* Hyperthreading.

Has anyone reading this noticed any particular trends in terms of Hyperthreading and other BIOS settings?

I have. I had a situation some years ago that led to experimenting. Computer far from maxed out but dropout issues. Hyperthreading off was the cure. However, since then I upgraded (or whatever you want to call it) to 64 bit code Reaper. Hyperthreading on/off flipped. I know there's more to the story. Probably one of the plugins I was stubbornly using or maybe the 32 bit vs 64 bit code. It was an edge case in the long run I think and I haven't looked back. But I also have a grossly overpowered computer for audio so there may be some 'out of sight, out of mind' here. The ringer back then would have been some 300+ track mix at 88.2k or 96k and mixing to 5.1. I had something up to 400 tracks the other day with no issues. High track counts aren't a problem. (A lot of parallel processing, subgroups, and tracks for little unique mix treatment bits. The whole album of mixes in the same project just because. And a helping of general sloppiness.)

I'll add that I believe some buggy plugins only show their flaws when you have a large project and/or a lot of parallel processing and bus routing. Especially if the plugin doesn't report PDC needs correctly to the host DAW. Routing a challenging PDC needing board to begin with and then throwing a plugin like that into the mix kind of beats Reaper over the head with a lead pipe. Inserting a Soundtoys plugin into a large project, for example, is almost a guaranteed crash.