Hi all, Okay, so here’s a long tricky question that I’m seriously hoping someone can help me with! A high pitched chirp/click/zapping sound has been appearing through my computer recording setups lately. Here’s where it gets tricky. I first noticed it when recording a flute part through two different dynamic mics running into a VoiceLive Touch, a Kaoss Pad and into my laptop’s soundcard. The original recording was done in Audacity, but I noticed it showing up in AudioMulch as well. At first I chalked it up to some digital artifact from the VLT or the KP3. Incidentally, it didn’t seem to matter which audio driver I was using, one of the Windows drivers or ASIO. Taking the VLT and KP3 of those out of the system, however, did not help. I tried different mics, different cords, no difference. I started running the mics through my ART Gold preamp and then directly into the computer’s soundcard… still there. I bought two new condenser mics. Still does it. Thought it might be the optical mouse; still does it without it being plugged in. I considered that it might be a ground loop issue, but it still does it whether my computer is plugged in or running on its battery. Even so, I ordered a Behringer HD-400 Ground Loop Destroyer just in case, (which didn’t seem to help, but I think it was defective so I sent it back and am waiting for the replacement). However, when I called Behringer’s tech support, the guy I spoke with said that it sounded more like hard drive noise being picked up by the mics. And when I told him I was running them through the computer’s sound card, he suggested I look into a USB interface. This weekend I purchased the PreSonus 1818VSL USB interface, sure this would solve the problem. Not by a longshot. Using the AudioBox software, the AudioBox ASIO drivers, and running the headphones through the 1818, it still does it. Sometimes very loudly. The AudioBox software is a virtual mixer and when the chirping is loud (with the gain raised significantly on the inputs) it’ll register in the meters, at least three quarters of the way up. With the gain way down in normal recording range, it’ll still often do it but in a much more subtle, chirping, tinkling effect. For instance, I’ve done test recordings of my piano and didn’t notice it through the headphones when I was playing due to the volume of the live piano itself, but upon listening to the recorded tracks, it’s present, subtle at times, louder at others. I will add that in this particular case, I noticed it more prevalently on the second input (of three mics), though they were all running in at about the same volume. For some reason, and this might be purely coincidental, it does seem to do it more on the second input, regardless of which mic is plugged in at the time. But of course it was doing it long before I even bought the 1818 so I don’t think there’s any defect in the unit. Even with the phantom power off, and three mics plugged into the 1818, it started making the chirping noise. So then I decided maybe it’s the cables. I unplugged the cables so nothing was running into the 1818 and I didn’t really notice any chirping. So then I figured maybe it’s the mics (even though it’s done it with old and new mics, both dynamic and condenser.) So I plugged in a TRS cable and plugged it into my guitar. And the chirping came back! At least I know the mics aren’t picking up the HD noises since it does it with a guitar too. But at this point I’m thoroughly at a loss! If it helps, I’m running it into an HP dv7 laptop. I’ve never really had issues in the past. I’m guessing it’s something internal to the computer, but I don’t even know what since it does it regardless of whether I’m using the internal soundcard, drivers, or jacks, or the 1818 USB interface. And I should add, it doesn’t do this when I’m just listening to music, videos or anything else on the computer. It’s purely happening when sound is entering the computer in any way, and it is audible in both the headphones as it’s happening and on the final recording. I’d really appreciate any help on the matter! Thanks much!