Crackling like old vinyl record

 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

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..

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

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?

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.

Cutting the network had no effect, yes I'm running at 44.1/24, internal soundcard is deselected. When I export MIDI files as *.wav or *.mp3, the glitches are still there, but of course, now they occur in exactly the same place each time. Fritz

Are you using any other plugins aside from TTS1?   A demo perhaps?    They have a tendency to insert white noise at somewhat regular intervals.
 

 No, I am using a clean fully licensed Studio edition and the glitches occur both in the case of a single TTS1 synth present as well as one TTS1 and one other (e.g. Cakewalk Sound Center).

I have re-imported a *.wav file into Sonar to look at the waveform. Even at maximum magnification, I could not find any visible irregularity. What I find very hard to believe is that a fairly powerful system and a standard SONAR configuration are having problems reproducing even simple MIDI-files (2 instruments only). If it were a "capacity"-problem of any sort, it should get worse with more complex MIDI-files - which it doesn't. I have now tried the simplest possible setup: One track, one synth and an instrument with a continuous tone. I press a key on the keyboard controller and the glitches randomly occur as before, they appear to be a combination between a very short dropout and a short scratchy/clicking noise. Fritz

I am talking of MIDI tracks - there are no wave detailed profiles. The glitches become located and permanent when I export MIDI to Audio

Why don't you select the MIDI track and the corresponding softsynth track and do a Bounce to Tracks and see if the glitches show up in the resulting audio track. Maybe that may give you a clue to the issue. 

What do you have the # of samples set to in the ASIO control panel for the AP192? That's an important setting.


I agree you shouldn't be having an issue, but since you are the only one having this problem, its not a bug. It has to do with your setup. We just have to figure it out and correct it. 

 after bouncing to track, I get intermittent glitches on the audio track as well. I have tried several settings for the AP 192 (128, 256, 512), no difference. No, I am not overdriving the synth, it stays well within the safe zone. My output is purely analog from the breakout bundle of the sound card (2 mono TRS Connectors) to the woofer/amp (2 x RCA).

If the re-imported waveform didn't show any abnormalities then you may be looking at a physical problem like a speaker cable or power cord to the speakers.  To test copy wavefile to CD/Ipod or other device and playback on a different system thats does not use the speakers your are currently monitoring with.   Another thing to try would be to unplug 1 speaker at a time to isolate if there is a problem with 1 speaker.