So you bought one of these Firewire audio-interfaces and tried them with your PC, but you can hear crackles, drop-outs (pauses) and all that unpleasant stuff. Let me show some possible reasons, and see if your setup has similar problems.

All three versions of audio-interfaces use Firewire bus to exchange data with a computer. All of the devices are very sensitive to what’s going on in this bus. When data stops coming, you hear the silence. When an audio stream resumes, you don’t hear silence. These pauses are called drop-outs and happen because your PC is busy with something that claims to be very important while on practice it’s usually a malfunctioning device driver.

What’s going on?

We are going to need a very small application that will show us how the most vital part of our computer (in relation to the AU of course) behaves – DPC Latency Checker. When you start the tool it begins its measurements cycle. It reports the time it takes for events to come through indicating the load of the event queue.

  • If your computer is healthy, you see almost flat line in the range from 0 to 500 us. The bars are green.
  • If there are potential problems, but still you it does well, there can be some occasional peaks up to 1000 us.
  • If your current configuration isn’t suitable for real-time audio / video, you will see red bars.

If you are reading this page, you most probably see the red bars as I did, and I’m going to show some possible ways to fix this. If your system has an almost flat line of green bars and you still hear crackles and glitches, you may need to reconsider the allocated amount of buffers in the control panel. Perhaps it is too low. Try starting with 1024 samples and go down until it loses stability. Now let’s start trouble shooting. Remember to reboot your PC after every change and check if the problem is gone with the latency tool.

Patch the OS

The simplest thing you can check is the two patches for Windows XP SP2 that enable back high-speed Firewire (800 Mbps) and fix compatibility problems with some devices. Both of them are important and you’d better had them installed.

Disable Useless Drivers

Now, if it didn’t help, open the documentation for the DPC Latency Checker and start reading. They suggest to disable as many drivers as possible while monitoring the DPC Latency state with their application. Do that, but be sure to read the list of essential drivers and don’t try disabling them as it will most probably lock you out of your system. BE CAREFUL and DON’T FORGET WHY YOU ARE DOING IT in excitement.

Tweak BIOS

If it didn’t help, reboot your PC and enter the BIOS. Try disabling everything possible there: unused serial (COM) and parallel (LPT) ports, devices, power management etc. Record the changes and be judicious. Don’t fall into extremes and keep your system functional. Check with the latency monitor upon startup.

If Nothing Helped

In my situation with the HP Compaq nx9005 laptop and Windows XP Pro SP2 with both patches installed and all unnecessary drivers disabled I still had my Konnekt 8 sound like crap. I reported it to TC Support, but they weren’t of a huge help and after a month of exchange I gave up talking to them, agreed to be a dumb user, filed the report and closed the ticket. I can’t believe that they still claim their hardware / software have no major problems (but this is another story) and be compatible with Mac’s (this is also a different story).

By sheer accident I found the reason for my problem and see if it’s yours too. I have an old PS/2 mouse that I can use with my laptop, and I do. Yesterday I was reading some forums in the comfort of my couch. I didn’t have the mouse attached and used the pad all the time. I stumbled upon some trick I wished to try that required rebooting. So I did and to my greatest surprise the DPC Latency Checker showed the thin flat green line of bars. Wow! At last! I was happy and went to bed on this major note. In the morning, I connected the mouse and the interface only to find these annoying red latency peaks back. I didn’t understand, but now I do.

The difference between two setups is the MOUSE. Yes that old PS/2 MOUSE. The crappy beautifully signed official Microsoft driver appeared to be a major pain in the neck. I unplugged the mouse, rebooted and the problem had gone. I listened to music half a day before I decided to plug the mouse in a controlled experiment and the second I did that, there were all sorts of peaks and audio drop-outs returned.

The obvious step was to try a different (USB) mouse and it worked like charm. So, I’m going to get one tomorrow and finally start enjoying the power of my Konnekt 8!

Here’s the brief summary of places to check:

  • Install patches: KB885222 and KB904412
  • Disable every driver you don’t need, service you don’t want and kill all applications you don’t use while checking the progress in DPC Latency Checker.
  • Disable every unused port and feature in your BIOS
  • Unplug that old crappy PS/2 mouse for Christ sake already!

Here’s the forum branch discussing all possible problems with these audio interfaces that will help you to kill four-five hours.

My suggestions on making Konnekt work on Mac OS X are in the other post.