Hi,

 

Ever since I have been using FS2004, I have had sound popping issues, that were never really fixed. Now that I'm on FSX on my new PC, I still get the sound popping and crackling. It gets quite bad sometimes. After some testing and online research, here is what I conclude for my system:

 

-It's not sound card related. My PC has a dedicated audio card (Delta 1010) and I thought something might be wrong with it's settings. However, even my wireless USB headset has the crackling sounds, and that device uses a separate audio driver.

 

-It doesn't seem to be autogen related. Since my old computer was pretty low-end, I'm used to running the sim with no autogen at all (I don't care that much, frankly). However, I have tried running autogen at sparse (my now preferred setting) and even at max, and I still get as many pops and cracks as autogen off. Oddly, the sim doesn't really lag much more when I crank up the autogen, so I don't think my issue is the same as the other posts mention (autogen - tree related)

 

-The BufferPools fix doesn't help at all. In one tweaking guide, it is said to use certain BP values to reduce sound popping, the fix changes nothing. I can't use BP=0 because I get graphic artifacts, but that doesn't help either.

 

Now for the interesting part... I have noticed the sound issues really only begin after either an ALT-TAB or ALT-ENTER. I prefer flying in fullscreen for now, as I get better performance, but I know that when I will fly longer flights, I will be in windowed mode most of the time. It seems that the issues begin after the initial ALT-TAB or ENTER I do. For example, I just tried sitting on the tarmac @ LAX in fullscreen, then hitting ALT-ENTER, and bam, I already get pops and cracks, the sound is "cutting out" for split seconds. After several minutes it seems to go away, but randomly returns and increases dramatically after an ALT-TAB or ENTER.

 

Although I now have a couple of PMDG and Carenado aircraft installed, my FSX installation is relatively fresh, and I think I had the sound problems even after the first install. I reset my fsx.cfg file today as well.

 

Note that I am running Windows 7 64 bit. Specs are on the left.

 

Thanks for any tips!

 

Phil

Thanks for any tips!

 

In my experience sound crackling and distortion in FS is caused by frame rates which are too high. You don't mention what you are getting, but I've always been able to fix the issue by placing a limit on the frame rate, or lowering the limit till it stops crackling. You can either use the internal FSX limiter, or, better, the one in the nVidia driver and settable in nVidia Inspector (assuming you have an nVidia card).

 

On my current system anything over about 60 fps gives distortion on occasion, but I limit it to 30 fps. On my previous, lesser system, anything over 40 caused it. I think it must be something to do with how often FS tries to do things on the audio channnels and the limit may be the main motherboard PCI bus speed, which explains why the effect changes with different systems. In your case maybe the ALT TAB / ALT ENTER is freeing something up enough for a burst of speed (fps) for a time?

 

Regards

Pete

In your audio device settings in W7 under speaker settings and then advanced, try lowering the sampling rate to 16 bit / 44100hz (CD quality). This fixed all my crackling problems under FS9 and i haven't had any problems under FSX, should give better FPS too (i think?).

My sound card only has the "Studio Quality" (which is 24-bit audio) and "DVD Quality". I lowered it to DVD and it improved a lot, thanks! As for my headset, I lowered it to CD Quality.

 

Pete, I think you're right!! I had actually set my nVidia Inspector to lock at 60 fps, because it gave me very nice fluid motion in external views. However, I still had 25-30 fps in VCs. I tried to lock at 30 fps using the internal limiter, and it didn't change anything. When locking at 30 fps with Inspector, I dramatically reduced the amount of sound popping! I think your theory is valid.

 

After a bit of tweaking i decided to lock at 35 fps. I applied both fixes, I'm not sure what fixed it but it's working now! I just completed my first FSX flight with 0 issues! 45 minutes in the NGX, + another 45 on the ground (still learning) and I had absolutely no sound pops, a part from the odd 1 or 2 cuts during the entire session, but that's probably scenery loading as it is accompanied by a short freeze in graphics.

 

Huge thanks to you too for your advice! I finally have my FSX working just the way I want it to.

I guess I got lucky on my previous flight!

I took off again after the same flight, without quitting FSX nor ending the flight, and experienced my sound issues on the ground and on takeoff. After about 6-8000 feet, I got a lot less distortion. This was all with 35 FPS locked externally and autogen sparse. I got a little bit of pops and cracks during the 30 minute cruise. When the pops restarted again at around 4-6000 feet AGL, I decided to set autogen to none. That helped, but it still didn't fix the issue... I guess I will have to learn to live with it.

 

I will continue testing, maybe I should lock to a lower framerate (which would suck because it's quite consistent at 35) or maybe I need to live with no autogen, which is annoying but I fly mainly for the systems modeling, so it isn't THAT bad.

Sorry, I can't find a way of editing my last post?

 

With my headset I recently got (Logitech G930), the cracking is much worse. Probably because Windows forces the headset to be a 7.1 surround audio device. If I load up an add on airplane at LAX for example, I get strange cuts in sound almost perfectly every second, it's very strange.

I used to have sound cracking problem. I inserted AffinityMask in my fsx.cfg so that fsx only use 3 cores of my Q6600, freeing 1 core for windows, since then I get no more sound cracking problem.

Phil,

 

Go to the provided link and download the DPC Latency Checker Tool. Take your time and read through the documentaion for the tool and how to use it. Then while running FSX run the tool and check your latency. Also check your latency with and without your USB headset being utilized and see if there is a difference.

 

Check your latency first and then move on from there.

 

Get the DPC Lantency Checker Tool frome here: http://www.thesycon....ncy_check.shtml

 

Regards,

 

Bob

I have quite a busy weekend so I will try out the latency checker and post results most likely tomorrow or Monday, thank you very much for the info! I'll let you know in a few days.

 

As for affinity mask, I let Bojote's tool set it for me, it's set to =5. On my dual core i3, that makes the physical cores (0 and 2) run FSX. When it runs, in fact:

 

Core 0 is at 90 to 100%;

Core 1 is at about 30%;

Core 2 is at 75-100%;

Core 3 is at about 20%.

 

Maybe I could try without the affinity mask, perhaps that could help my sound issue? I don't really know.. I'll start with the latency and get back to you a few.

 

Thanks again!

 

Phil

Try AM=14 (4 cores with HyperThreading ON).

 

AM=2 (2 cores with HyperThreading OFF).

 

Dave

Solved!!!!!

 

With the DPC latency tester tool, I noticed my latency was fine with the speakers, but terribly high (always red) with my USB headset. That caused stutters and sound issues with FSX (I hadn't realised the stutters were related. Oddly though, only FSX + my USB headset caused this, the headset is fine with all of my games.

 

I tried to replace my affinity mask of 5 with 14, and that fixed everything! No more sound issues and no more stutter. Loaded up at KMSP (a very bad airport for sound stutter, for some reason) and the default ultralight, here is a screen shot of my CPU performance:

 

 

 

Altought it may look strange, I get pretty much the same performance I had with Mask=5, minus the sound glitches.

 

New question for you guys: Since I only have 2 physical cores, is AffinityMask=14 the same as having no affinity mask at all? I had read somewhere that since SP1, FSX handles multiple cores okay. Just wandering. With AffinityMask=14, it looks like 1 physical core and 2 HT cores are working very hard, and the last phyiscal core is only at 30%.

 

Thank you very much, I am very happy to have this stutter-free and nice sounding FSX!

Try this as it may work.

 

Turn your main winows and FSX sound down to 80%.

 

This helps with distorted sounds. You can always turn your uead phone speakers up to compensate.

Try this as it may work.

 

Turn your main winows and FSX sound down to 80%.

 

This helps with distorted sounds. You can always turn your uead phone speakers up to compensate.

 

That could maybe have helped in certain situations, but my issue was really a DPC latency problem, as it was also accompanied by visual stutters. In addition to this, even setting all volumes to the lowest possible setting (actually, even on mute) resulted in issues. Changing my affinity mask seems to have corrected the problem, for now.

No, AM=15 is the same as no AM, with HT on.

 

Dave

Turns out, after even more testing, that my problem came from FSInn. For some reason, with the FSInn microphone setting set to "Default mapper", I get extreme amounts of DPC latency. If I set the FSInn microphone to anything other than "Default Mapper", it's all good. I thought the affinity mask had changed something, but it doesn't seem like it after all. FSInn was the problem.

 

I still get a bit of sound popping, with an okay latency. This is caused by high framerates? I'm locked at 35 though, it still does it. On takeoff from LAX yesterday, I had the most extreme stutter I have ever had in FS, but I think it is related to FSInn's multiplayer planes (since this is my first VATSIM flight, I will need to do some more testing)

 

Thanks again!