CAD U37 USB Condenser Microphone: beeping in playback

Hello all,
I recently invested in some cheap recording equipment just for fun. I have a Windows 8.1 Nextbook, and bought a USB microphone without remembering that a nextbook does not have a USB input. I didn’t get discouraged, however, because I immediately purchased a USB OTG adapter for my nextbook. I connected the adapter to it, and then plugged in my CAD U37. After I tested the mic, I noticed something strange in the playback. Here is an audio clip of what it sounds like:

Obviously I can’t record anything with that obnoxious beeping noise. I’m not sure if it’s the OTG adapter or not, as I’ve used the microphone without any issue in my friend’s laptop. I’ve tried everything I can think of. If anyone has any ideas, it would be greatly appreciated.

That’s an extreme example of “frying mosquitoes.”

Listen after I stop talking.

That’s the computer’s digital trash getting into the microphone sound. It only happens with microphone systems and you can’t get rid of it in post production filtering. Noise Removal doesn’t work. Sorry. One poster complained she could hear the hard drives spin up and down behind her dialog.

We don’t know how to fix it. That’s the simple version. It’s a personality problem. People have found relief by shortening the USB cable and making it longer, putting a wall-powered hub in the chain and taking one out. Wrapping the USB cable around a cucumber, stop recording on Thursday, etc. etc. etc.

Someday I’ll rip apart a USB connector and see where it’s coming from, but until then. Good luck.


Back here on earth:

It seems it also only happens on cheap, inexpensive microphone systems that directly use the USB 5 volt bus in the voice signal. Much more expensive USB microphones and amplifiers with formal power supplies, regulators, filters, etc, don’t appear to do that.


You are the poster boy for a Zoom H2.

That’s it on the rock there.

Or you could just keep doing what you’re doing…


It’s probably power supply noise passed-through the adapter, not the adapter itself.

A powered USB hub might be worth a try. (A USB hub that’s powered from a wall wart power supply.) People usually recommend against using a hub with USB audio devices, but in this case it might help. It’s probably best if you don’t plug anything else into the hub so the data-path doesn’t have to be shared.

That’s the “Put The Hub In” approach.

That’s a valid approach to double your USB cable reach. Put a hub in the middle and you can get 12 feet (4M) of USB cable instead of the usual 6 feet (2M) cable length. If you’re using one of those cheap million-foot USB extension cables already, I would stop.

I missed one. Someone claimed higher quality, double shielded USB cables can work wonders. I believe it. We had a series of digital cables at work that had to be trashed they worked so poorly. It took us a while to figure out every time we had a failure, one of these cables was right there.