Since SU4 Release, we’ve been receiving comments from users that C17 Sounds are “cracking” on Console (Series X and Series S - no reports on PS5). It’s very inconsistent - does not happen to all users, and seems to be more noticeable in external view than cockpit view.
This issue does not exist on PC, nor I’ve been able to replicate locally on my Xbox Series S.
Any ideas? @FlyingRaccoon
We have also seen this issue on the XB1 on Xbox, as well as our own Super Hornet audio (which the XB1 is derived from) where upon entering drone view to capture flyby sounds, the game crashes (Xbox only). This has only been an issue since SU4 was released.
Hello @vantech
I’ve had this reviewed by our sound engineers and this seems to be an optimization issue on your side.
The Wwise profiler allows to track the amount of voices being used as well as CPU usage.
Flying above the ocean to make sure no other object interferes, here’s what the profiler shows with the C17:
There are too many voices (250 physical + 511 virtual) and you can see how high the CPU usage is (this is measured on PC)
On console, with less powerful CPU, this can reach 100% and will have side effects on audio, possibly the “cracking” you are referring to.
For comparison, here’s what it shows with the Boeing 747:
Here’s an article from Audiokinetic about CPU optimization:
Wwise CPU Optimizations : General Guidelines | Audiokinetic Blog
Our sound engineers suggest you should stay under 100 physical and 200 virtual voices.
To do so, the most obvious thing you should do is make sure you used the continuous play mode on your blend containers as much as possible on your engine and environment sounds, as described in our documentation:
Engine Audio Setup
Using Switch container to switch between sources depending on if you are in internal vs external cameras can help reduce the amount of active voices a lot as well.
And finally, ensure your voice advanced settings are configured to turn them into virtual voices when not in use:
You seem to be using step mode, which means for example the voice for 0-10% RPM will still be active even if you have 100% throttle, and this will be the case for all the voice range not being used, and on 4 engines.
This quickly add up.
The list of voices in the Wwise profiler can help you with this.
Basically, if you see a voice that has no volume, you should ask yourself why it’s not virtual.
Regards,
Sylvain
Most sound sources are already configured with “Continuous” blend containers, as most objects require this setup. We’ll take a look at the optimization of physical/virtual voices.
The strange part about this is that the audio has been working great, without issue, until the most recent Sim Update (SU4) was launched. I am wondering why it was working great before, and now we are having issues.
What changed to make this issue apparent?
Ive seen 3 live streams where they had this issue with default aircraft
The “Send to virtual voice” part might not be enough.
With blend containers play mode set to continuous, the voices that are not used should be stopped completely.
There are way too many engine voice visible in the profiler, with voice volume so low they will not be heard anyway.
You can see this in the profiler voice list: voices are showing volume below -100 or even -∞ but are not virtual. (illustrating with the wind voices)
We can’t really tell which voices are problematic, as their name cannot be seen without having the Wwise project.
But for example, with throttle set to 95%, only the voices that are currently being used (90 and 100% for example) should be visible in the profiler.
On first review by our sound engineer, voice saturation caused by the audio thread reaching 100% of usage was an obvious possibility.
I reached 80% of usage on PC, flying the C17 in the middle of nowhere, so on console and around a busy airport, that’s very likely.
But there may be something else involved, I am not ruling that out.
If we keep having similar feedback on other aircraft, we’ll probably review this further.
I’m not sure how you recorded the video above but the crackling keeps going after the sim has crashed so we don’t think this is related.
Could you point us to a video showing it if you still know how to find it please?
Regards,
Sylvain
I can here it at 45:40, but this is a different issue.
He has stutters, and this sometimes affects the audio thread and can cause the crackling sound we ear.
The is a general issue, and is not related to the aircraft being used.
This is different from the first 2 videos posted at the top of this thread, where the sound saturation occurs continuously, with no stutters in the rendering, which is more indicative of the “voice starvation” issue we discussed above.
Regards,
Sylvain
I’ll do some digging, perhaps some of the “under the hood” optimizations are now pulling slightly more resources off the thread that audio is processed? That would by my only guess as to why we’re seeing issues like this pop up.
Regardless, we will attempt to optimize the number of voices active in the scene. Thanks for the info, @FlyingRaccoon 
Yes, there has been a few architecture changes lately and it’s possible that the audio thread is a bit more sensitive to this than before.
But it has not been designed to handle so many voices anyway.
I’ll close this as “by design” for now, let us know if you are able to optimize this enough for the issue to disappear.
Regards,
Sylvain
Do you have any suggestions to the issue that I brought up here regarding some users reporting crashing on the XB1 and our Super Hornet audio when switching to “drone” cam (for capturing flyby sounds).
Please create a dedicated bug report for this and provide repro steps with as much precision as possible.
