Old 08-08-2018, 02:24 PM   #1
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Hi everyone,

in the middle of evaluating Reaper coming over from Logic. Slowly getting used to the many quirks and beginning to like the things you can only do with Reaper. If Logic is a Mercedes then Reaper is a Ferrari-held together by duct tape!

I've had literally hundreds of issues come up and most of them have been solved by just reading through this excellent forum.

One thing I cannot figure out though is why the RT CPU suddenly jumps from a stable(say 2-3 minutes) 3% to 20>30>40>50 etc, playback stutters and then goes back to 3%. I've never seen this before in any other DAW. Either you can play your session or not, there is no "sometimes".

Of course I can do more freezing etc. but this is not what I came here for! Total CPU is 25% so I'm not anywhere near maxing out my Mac and neither is any single track over 2% which to me seems the threshold for maxing out one core.

I've also pretty much ruled out the audio interface and temperature throttling and tried dozens of permutations of the buffer and anticipative FX settings. What am I missing? Hopefully something really stupid

Thanks for any insights...
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Old 09-12-2018, 11:46 AM   #2
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Hi,
Do you have any tracks in record? Does it happen at the same spot? All projects? Control surface connected? Does it jump w/o intensive plugs?
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Old 09-12-2018, 01:28 PM   #3
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Hi,
Do you have any tracks in record? Does it happen at the same spot? All projects? Control surface connected? Does it jump w/o intensive plugs?
Thanks for chiming in. There are no tracks in record, it happens consistently in all projects and repeatedly at the same spot. There is no control surface connected, and like I said, when I freeze everything or use lighter plugs it doesn't happen.

The reason I posted in here is that somehow Reaper can play a maxed out session that most other DAWs couldn't which is great but it just baffles me that it can "run out of steam" after 2-3 minutes with about 30 seconds of stuttering before getting back to normal. This is not the end of the world but a bit of a vibe killer nevertheless.

Any other ideas?
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Old 09-12-2018, 02:12 PM   #4
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Hi,
Same spot huh?.......any hidden tracks? Do you use a song template? Or track template?
Can reaper mac do a portable install?
Any midi connected?
Any downloaded scripts running?

Really throwing spaghetti now.
Oh..any hidden automation?

Does this van get good gas milage? :-)
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Old 09-12-2018, 02:49 PM   #5
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This van does well on gas-especially if you're spending most of your time driving it downhill!

Thanks again for throwing up some more possibilities but there's nothing hidden or unusual in my projects as far as I can tell. I was hoping for a certain combination of the buffer settings that folks on here have found optimal over the years. I'm now using 1024 samples/1000ms pre-rendering which gives the most workable results. I've tried dozens of permutations and workarounds-apart from the portable install which sounds like a long shot-and still the problem persists.
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Old 09-16-2018, 11:44 AM   #6
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Hi,
Huh.
Well I've had issues twice with a messed up INI file. A portable would expose that. But that's since 2007.
Can you upload a small version of your "autoload"? That exhibits bad behaviour?:-)
Old time logic user here:-) as a matter of fact I started with creator on Atari.
Have you looked at the track manager for any hidden tracks? The thing that it happens in different projects at the same location is what is steering me.
Good luck

I use 128 or 256 buffer. If its the very end of project timeline ...final mix.... I might bump it to 512. Everything else is pretty stock.
Maybe some screenshots of the rekavent audio settings your running may help. Or the INI file or whatever its called on Mac...I assume.
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Old 09-16-2018, 12:53 PM   #7
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Thanks for your additional suggestions but I think what is needed here is someone who is more computer-savvy than either of us.

I don't have an autoload or template; what I was referring to was simply that if I loop a section the problem crops up after a while even if it's exactly the same audio with the same plugins. First it plays fine, then it starts stuttering, then it plays ok again etc. etc.
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Old 09-20-2018, 09:52 PM   #8
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Do you maybe have audio in your project that has a different source samplerate than the samplerate of the project and the samplerate of the audiodevice you are using ?

Also, do you have maybe stretchmarkers in audio and you have set playback resample mode set to a very high setting (in project settings) ?
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Old 09-21-2018, 04:38 AM   #9
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Not much help but: I've had problems I didn't have time to try to understand. I just make a new project and copy the audio over and the gremlins go away.
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Old 09-22-2018, 05:45 AM   #10
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Thanks guys-won´t be able to test anything for another 10 days as on a rare Holiday. The problem occurs in every project though so not limited to any particular project or audio file. It also occurs when there are no audio items, just MIDI ones.
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Old 09-22-2018, 06:59 AM   #11
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Ha then my post was completely worthless!

I hope you get it sorted, pls let us know.
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Old 09-22-2018, 07:06 AM   #12
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Does it do this if reaper is idle? Maybe it's a VST denormal issue. That's rare but possible; which plugins are you using? If using plugins can you bypass them one at a time and find one that seems to be the most related to the issue? If so, let us know which it is.
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Old 09-22-2018, 07:55 AM   #13
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Quote:
Originally Posted by Uncovered Pitch View Post
Thanks for your additional suggestions but I think what is needed here is someone who is more computer-savvy than either of us.

I don't have an autoload or template; what I was referring to was simply that if I loop a section the problem crops up after a while even if it's exactly the same audio with the same plugins. First it plays fine, then it starts stuttering, then it plays ok again etc. etc.
Does this only happen when looping a section of audio?

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It also occurs when there are no audio items, just MIDI ones.
Do all your projects contain MIDI?


Could be a couple clues to at least narrow it down.
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Old 10-03-2018, 05:09 PM   #14
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Thanks again for the additional suggestions. I'm surprised that nobody has seen-let alone solved-this issue before since I don't think I'm doing anything unusual.

I've looked at the various pointers that were mentioned here like denormal, looping sections, using MIDI only, audio only, sample rates etc. but nothing made a difference. I also don't think that it's a particular plug-in but cannot test every single one since I have hundreds like many of us.

Using less CPU overall always cures the issue but I'm still perplexed as to why a close-to-the max system plays ok for a few minutes, then "comes up for air", and after a minute or so of stuttering goes back to normal. Somehow I'm thinking that if my Mac/Reaper combo can play the project at all, it should be doing so for as long as I want, if I could only tweak things a little with the right settings in Preferences. But no luck so far...
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Old 10-03-2018, 06:09 PM   #15
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Are you running a SSD?
An older slower spinning drive could do such a thing.

Maybe also post a pic of your Reaper Preferences/Audio/Device page
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Old 10-03-2018, 06:15 PM   #16
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but cannot test every single one since I have hundreds like many of us.
You can but you can't add 100 to a project then do it. Priority #1 is to list/figure out which ones are loaded when it occurs. If you can't reproduce the issue with no plugins loaded then you already have part of your answer.

Quote:
Using less CPU overall always cures the issue but I'm still perplexed as to why a close-to-the max system plays ok for a few minutes, then "comes up for air",...
I can figure it out but that's far more complex than taking the first step of narrowing down which plugins are running first. I could give you way to create a memory dump when it hits ~n CPU% but it has to only hit it as part of this issue. I could at least surmise from the memory dump what's causing the CPU if a plugin - if purely reaper (which I doubt) it would be harder due to lack of source code and symbols. However, it really is at least partly on you to see if you can determine which plugin is involved - a start is to open Reapers performance view and see if it shows a particular track going high on CPU when the issue occurs.

As far as less CPU resolving the issue, makes me think the single thread the services the audio driver is the problem.

If you have done this and I missed, my apologies.
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Old 10-05-2018, 09:29 AM   #17
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Hi,
Nice mystery. Maybe...what Mac....what operating system...etc....might help. Just not sure if op really wants help.
No one has "solved" the problem because maybe we don't have that problem. I know I don't.
Good luck
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Old 10-05-2018, 09:52 AM   #18
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Ok I've done some more testing but have not got any further with it other than discovering the "RT longest-block" display.

I did try and swap out some plug-ins but since the issue happens on every mix I very much doubt that a single plug-in is to blame. And if it is, I haven't got the time to test hundreds of plug-ins. It's not simply a matter of disabling one at a time because the problem is related to overall CPU use so each plug-in would have to be replaced with one with the same CPU use.

The issue also happens with MIDI items only so in this case an SSD drive wouldn't help.

In my decades of experience with troubleshooting Logic issues on the Mac, I've found that staying "close to the error" is the best bet and "out-of-the-box" or generic solutions(resetting P-RAM, repairing permissions etc.) rarely work.

In this case it is the RT CPU thread that is being fed more information than it can process and the only solution seems to be freezing tracks and splitting channels and busses to shorten the plug-in chains.

As my last hope, I've attached my buffering settings here. The requested block size is 1024. I could increase some of the settings but then there is too much lag time between tweaking a knob and hearing the result which is even worse than having to freeze or split more tracks.

The reason why I reached out here was that I've never encountered this problem in Logic-it would simply grind to a halt when you maxed it out whereas Reaper manfully soldiers on, limping a bit and then recovering for a while. That's why I thought there could be a small tweak that would make my system go the extra mile. And I was hoping that my problem was very common and "old hat" to more experienced users.

Thanks again for all the suggestions so far.
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Old 10-05-2018, 11:22 AM   #19
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In this case it is the RT CPU thread that is being fed more information than it can process and the only solution seems to be freezing tracks and splitting channels and busses to shorten the plug-in chains.

As my last hope, I've attached my buffering settings here. The requested block size is 1024.
Based on what I've read, I agree with ^this. There is always a ceiling somewhere on every system and you could simply be hitting it. That said, and if this is the case the only remaining check is LatencyMon - if it shows a problem then some driver/hardware could be causing unnecessary DPC type delays which effectively lowers that proverbial ceiling. Apologies, if you've done the LatencyMon test already and I overlooked it.

The only other thing I can think of beyond hitting the ceiling is some users have issues with plugins on their master buss eating more CPU than they should - if that were the case the solution is usually to send all tracks to a single folder or buss, putting the master FX there then sending that to the master.

Good luck!
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Old 10-05-2018, 11:40 AM   #20
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In your screenshot, I see you've been changing thread behaviors possibly? Be very careful there as what they intuitively say isn't always the result you get! - in other words setting the thread to very aggressive could potentially cause thread A to starve thread B or the audio thread FYI and cause more pops/clicks etc.

I use Highest (recommended) with Auto (Experimental) FYI but again, don't assume those settings automatically result in the behavior you think because it's managing thread scheduling and context switching, and it is NOT as simple as "Crank everything to the max" and things get faster. Sometimes (but not always) the best setting is the exact opposite of what you think it should be.
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Old 10-05-2018, 08:59 PM   #21
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The tools you suggested are Windows only and I'd already figured out the "fake master" trick by myself but the thread settings you mentioned(Highest and Auto) did make a verifiable difference-the mix played for twice as long before falling over. Many thanks!

I then changed the core settings at the top of the page to 12(the number of physical cores on my machine) from 24(number of virtual cores). This enabled the mix to play indefinitely or at least until I got bored with it-progress!

Of course I then piled on more plug-ins until the dropouts came back but there was none of that "sometimes it plays, sometimes it doesn't" behaviour that prompted me to open this thread.

I will do further testing on other tracks and report back if I find anything of interest.
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Old 10-06-2018, 08:25 AM   #22
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I then changed the core settings at the top of the page to 12(the number of physical cores on my machine) from 24(number of virtual cores).
This sounds like you have hyperthreading enabled. You would only see the physical cores listed otherwise. Disable hyperthreading if so. Reaper does better managing its own CPU threads. (At least here. Some people see the opposite in other discussions on this.)
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Old 10-06-2018, 08:46 AM   #23
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Yes I do have hyperthreading enabled. Disabling it was one of the very first things I tried when switching to Reaper after having read some of your contributions on the subject. In all my tests my system performed better with hyperthreading enabled so I'm on the other end of the spectrum here.
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Old 10-06-2018, 09:32 AM   #24
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Yes I do have hyperthreading enabled. Disabling it was one of the very first things I tried when switching to Reaper after having read some of your contributions on the subject. In all my tests my system performed better with hyperthreading enabled so I'm on the other end of the spectrum here.
Well shoot.
Sure would like to see the dots finally connected on this one one day!
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Old 10-06-2018, 08:46 PM   #25
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PDC -- Maybe this can shed some light. I've had enormous issues with Reaper RT CPU going crazy with specific types of routing and PDC. Are you using nested folders? Do you have sends going from a nested track out to a different folder? Common occurrences might be a Kick in a PERC folder sending to a Bass in an INST folder to sidechain, and the INST folder has some kind of high-PDC plugin on it. It's actually impressive that Reaper can figure this out at all and keep things in sync, but you can see how PDC can really cause issues when sends are involved because so many things depend on each other.

This might have absolutely nothing to do with your project lol, but maybe! If so, you have some alternatives to nested track sends that you can try
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Old 10-07-2018, 11:45 AM   #26
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It's like you suspected-I don't use folders at all let alone nested ones so not really applicable to my projects but I run a lot of plug-ins with high latency values so there may still be something useful about PDC being a possible culprit-thanks!
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Old 10-12-2018, 08:27 AM   #27
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Shame there doesnt seem to be a Msac equivalent of the tools you can use in Windowes to identify the cause(s) of problems like this. Lucky me my Mac Mini still behaves itself, but I too would feel a lot more secure if there was an equivalent tool to say Resplendence,com`s latency/performance checker.

Anyone know of something like that for Mac?
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Old 10-12-2018, 08:44 AM   #28
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Speculation and probably not useful...

I suspect PDC can be crashed by buggy plugins. I know that if you stubbornly use a plugin that reports its latency incorrectly to PDC that you can crash Reaper to the point that you need to relaunch it. The scenario is you suddenly have dropout-like clicking and popping but no telltale of high CPU use or running out of ram whatsoever. At this point even removing the plugin in question doesn't just fix it. Still dropouts. You need to relaunch Reaper. This suggests that a buggy plugin (and specifically bugs with its reporting to PDC) can crash part of Reaper to the point it needs a relaunch.

I've also had issues with loading up too many very high latency plugins on a track. Daisy chaining them across two tracks cures this in that scenario.

It gets more ambiguous too...

Sometimes you have these buggy plugins but they only misbehave if the system is being pushed a little. I mean... that's kind of the territory we're in nowadays troubleshooting anything with computers. Whatever the last straw is turns out to be a red herring. But you do get some patterns. It's always one of the suspect plugins that leads to trouble.

So we can blame a bad plugin for this but perhaps this illustrates a weakness with PDC (or some other underlying service I'm not even aware of) in Reaper that could be improved?

Just to muddy the waters even more...
I've had the buggy plugin crash take out the class compliant audio driver before too. Or something like that crashed the actual audio interface. Either way, this scenario requires cycling power on the audio interface. So maybe it's not PDC being crashed, maybe it's the audio driver being crashed.


OSX includes a free tool to check up on what your computer and its systems are doing. Activity Monitor. I tried some app called Latencymon a number of years ago now after seeing posts around here about it. Probably not a fair test because it was in fact a Windows app (couldn't find a Mac version at the time) but it wasn't useful at all. May have been that running it with Wine in OSX was beyond what it could deal with. Trust Activity Monitor.


If I'm in "being careful" mode:
Restart everything before a studio tracking session instead of the fast and loose constant hot swaps.
Avoid the UA plugins (with their antiquated Protools-like pci cards).
Avoid the Soundtoys plugins with the incorrect latency reporting to PDC.

Everything is happiness and light. Live sound with below perception low latency to studio recordings with hundreds of tracks. Nothing ever goes wrong. Not even sure how to max out this overpowered computer.

Throw a couple suspect plugins into the mix and you see things!

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Old 10-12-2018, 02:30 PM   #29
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For me a big issue combo is using Waves GWMixCentric and Soothe on big folders when there are sends happening between folders.

Generally I separate my tracks into PERC, INST, FX, VOX groups. For the genre I produce, I usually sidechain-duck the entire INST group when the kick hits. If the INST folder happens to have these big-PDC plugins on it, the sends really mess with stuff leading to crazy RTCPU levels. Disabling the sends brings everything back to normal.

There's various threads about this, but AFAIK it isn't solved yet.
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Old 10-12-2018, 02:44 PM   #30
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For me a big issue combo is using Waves GWMixCentric and Soothe on big folders when there are sends happening between folders.

Generally I separate my tracks into PERC, INST, FX, VOX groups. For the genre I produce, I usually sidechain-duck the entire INST group when the kick hits. If the INST folder happens to have these big-PDC plugins on it, the sends really mess with stuff leading to crazy RTCPU levels. Disabling the sends brings everything back to normal.

There's various threads about this, but AFAIK it isn't solved yet.
I've also noticed that a more complex project with more complex routing like that can exacerbate the situation with suspect plugins. It still hinges on using suspect plugins though. It's like Reaper is normally unstoppable but Reaper with some buggy plugins in the project now has a more restricted headroom. (Headroom for the computing system. This is not a comment on audio headroom as related to dynamics.)
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Old 10-30-2018, 01:27 PM   #31
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Just a quick update from the OP. Thanks a lot for all your comments and suggestions so far. I've done a lot more testing and these are my findings:

1. The problem(intermittent stuttering) is still there in all its glory(well, most of it)
2. The initial successes I reported were with an artificial test mix-meaning that it was like a benchmark test running as many identical FX chains as possible until playback started disintegrating.
3. Reaper seems to work much better when the loads are evenly balanced but in a real mix this is hard to do and splitting tracks/busses only gets you so far-it can't be repeated indefinitely.
4. Reducing the maximum PDC per track to 4 times the buffer size and making sure there are no "outliers"(see point 3) did help a bit but didn't solve the problem completely.
5. Not using additional routings like sidechains on complex busses also helped a bit.
6. It didn't matter whether I used just MIDI, just audio or a combination of both.

Overall I'm still frustrated that I can only mix for 2-3 minutes before I have to wait for 20-30 seconds but happy that I can run complex mixes with hundreds of plug-ins where others DAWs(Logic, Studio One)would have capitulated with an error message and no playback at all about 50 plug-ins sooner!
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