Hi, I am running Sonar X2 Studio under Windows 7/64 Home Premium SP1, double core Intel 2.93GHz CPU with 8GB RAM. The soundcard is a M-Audio Delta AP-192. I have written a number of MIDI files with 2-16 instruments, mostly playing TTS1 instruments. When playing back, I can hear occasional crackling sounds very similar to a scratch on a vinyl record, but only intermittently. They don't occur at the same position on repeated playbacks either. Is there any setting I could safely try to play with to kill those soundbugs? Fritz

Check the latency on your sound card or audio device. What drivers are you using Asio or WDM?

How is your pc setup?

I ask cause this could be a shared  irq problem ,or  just something like buffer settings.... 

It is important to try to insure no irq's share with your audio device, that windows seems to like to do...if running win 7, you can no longer set irq's.

So the only way to get this done right before any software setup , is to use the bios and turn off redundant devices.

If you have a audio interface...type firewire/usb?...You do not need onboard audio....so you could turn that off in bois, freeing up that irq.
Also com ports if not in use can also be turned off.

What kind of mouse and keyboard in use? USB?...then perhaps turning off serial ports as well may help relieve some sharing of IRQs.

That said, ..setting up Win 7...tweaks?...turn off screen savers, and such sleep or hibernate features.
power settings , turn off monitor = never...advance settings Look into the hard drive tab and select to never turn off hard drives,
There are more setting to fiddle with...

After doing a check/setup on power managements profiles..save .

Setting up buffers/sample rates in software properly is dependant on bit rates you use I guess...

Someone else might have more to offer..

sounds like a sample rate clash.....
What sample rate is windows using and what sample rate is your project set to in Sonar and what sample rate is the M-Audio set to?

Thank you for your replies. I have tried all available drivers (WDM/KS, WASAPI, ASIO, MME/32-bit), currently I am using WASAPI; I have tried changing buffer numbers, latency - all to no effect, the random glitches still occur. The on-board sound device is turned off, unused serial ports as well. Any ideas left? Fritz

Check the Shared IRQ List in the system tools/system info/shared tab..
See where or What Win has done with your audio device, and what it is being shared with...perhaps ?... Moving the card physically...change slots might change the shared profile?

As IRQ are automatically shared on motherboards...You might need to read the manual, and find a way to select the best slot that way...perhaps?
Video card and certain slots share...gotta root that out...and solve for it....I guess? 

have you tried running "DCP latency checher"? (google it, download it, could reveal something)

could be your network causing thge problems, have you tried disabling it while you use the pc for music?

Make sure you're using ASIO mode.

Are you using 24 bit depth and 44.1 KHz sample rate? 

Make sure the onboard soundcard is not selected in Sonar. 

crackling sounds very similar to a scratch on a vinyl record, but only intermittently. They don't occur at the same position on repeated playbacks either.

People seem to think you are hearing dropouts. One would expect that to be more consistent as the high demand hits at the same point in every run through. Unless there is an intermittent background process that is stealing CPU cycles--see the DPC latency checker suggestion.

Could it be digital clipping? Again would expect it to be consistently in the same place, and show up as flattened wave forms or clipping indicator.

Could it be electrical "static"/micro-arcing due to bad connections or interference? That should show up intermittently on everything you play through that setup.

I had a similar problem with one of my computers. I found that my sound card was sharing an IRQ with an ethernet card I had installed. After trying a bunch of things I found that going into the properties of the ethernet card and disabling it while I was using Sonar got rid of the intermittent static/crackling problem.