Noise on USB Mic from software?

[deknow]

hi all,

i'm really confused here. i am doing a speech recognition install in an oncology office, and have a weird problem.

everyone is using the same usb handheld microphone from philips, and there are differant machines in differant offices.

there is static (significant) coming in from the usb microphone only for some doctor's computer profiles (the problem follows the windows user profiles from machine to machine. it does not seem to be hardware, as each computer is demonstraby quiet with some profiles, but not others...and the bad profiles always have this problem no matter which machine or microphon is used).

i've tried muting the other inputs in the volume controlls to no avail. what could be causing this? any help....i'm dying here

thanks,

deknow

[jksuperstar]

I assume audio just goes through the stand WDM panel "Recording Controls"?

Check to see if there's a rogue AGC setting on the mics (under Mic -> advanced settings, it shows up as "Microphone Boost" on my machine, but your USB mics might have something different).

That's all I can think of.

[Blue Hell]

Maybe check with the sysop if the doctors with trouble are all in the same user group and if there is something special arranged for that group ... like the xray viewer or god knows what ... this could be many things, a windows server has a lot of control over client machines ... well thats all I can think of ...

[deknow]

well, this was a weird one (i'm back at the hotel now). this might be instructive to someone, so i will detail what happened.

even though it was usb, i thought it must be something environmental (when we swapped computers into the room that did not show this behavior with the offending one, they suddenly had this problem, and the servers were exactly under this doctor's office.

fortunately, i was doing the install with someone else, so he could deal with the docs while i escalated the investigation. i downloaded an oscilliscope program for my laptop, cut the wire/connector off a headset mic (instant scope probe). you should have seen the look on everyones face when i was poking around in the ground socket of the electrical outlets

i wasn't convinced it was a ground issue (i had also tried removing the network cable), but it was all i could think of. i had taken my ground lifts our of my laptop bag before leaving home (i keep them in there for music stuff, but didn't expect i would need them). i found an unused powerstrip, and ripped the ground prong off with my bare hands . shut down the computer, and plugged it back in, and rebooted. i logged on as an adminstrator, and the problem was solved.

when the doctor logged himself back on, i went to show him how brilliant i was...and the problem was back, same as before. i had him log onto another machine that was working great(they have roaming profiles), and sure enough, there was the problem...that's when i asked for help here.

i checked the mic gain (and tried to see if manually boosing the gain a little would leave the noise floor where it was, and increase the s/n ratio...no luck).

it seems that his profile was originally a windows 2k profile. whatever the cause (i still have no idea), i was able to demonstrate to the it person (who was trying not to have to build a new profile for him...i don't know how hard or easy that is) that it was in the profile. we just logged him on as an administrator, and everything worked great (and more importantly, he was able to finish dictating his charts without a transcriptionist involved). tomorow, he is getting a new profile (which won't be done until after i'm gone).

deknow

[jksuperstar]

Wow. It be curious to see if you can save the registry for both profiles, and diff them somehow. I would guess it's something buried in there, since it's in the profile.