wireless mic buzz -Sound Forge - PC - MAGIX Community Forums Archive

Subject:wireless mic buzz Posted by: BobCole Date:6/18/2002 1:09:10 PM Have Sound Forge 4.5a. Frequently have to deal with voice recordings from wireless mic, which have occasional buzz right over important dialog. Is there a setting to mitigate this buzz? Noise Reduction only works somewhat (and for the buzz over the words, I don't want to use it at all). I have looked at Spectrum Analysis but cannot figure out where to go with its data. Related question: the recording path was: wireless mic into p.a. system. Channel 1 of recording was hardwired directly from p.a. system. This line has the bad buzz. Channel 2 of recording was a camera mic recording the speakers of the p.a. system. Channel 2 doesn't have any buzz at all. Audio is not as crisp, but clearly the p.a. system has a cheap chip that strips out wireless mic buzz. Do you agree? Can I use a similar process via Sound Forge? -- BC
Subject:RE: wireless mic buzz Reply by: Chienworks Date:6/18/2002 2:18:33 PM That buzz is often interference from AC line current, which is 60Hz. The sound system may have a 60Hz (and 120Hz & 240Hz for overtones) notch filter built in to help reject that hum. You can try using EQ to notch out 60, 120, and 240Hz. If you're only using Sound Forge XP, you won't have the ability to filter narrow notches though. The EQ curve filter is only available with the full version of Sound Forge.
Subject:RE: wireless mic buzz Reply by: havlicek Date:6/18/2002 3:35:54 PM Try using wires...balanced lines are important for that very reason. I forget the exact electrical explanation, but it's something like: you get the buzz on both "sides" (balanced cables are 3 conductor XLR or TRS 1/4") of the cables but 180 deg. out of phase so they cancel each other out. Wireless mics are nothing less than a radio transmitter so it should be no surprise that they can pick up line noise. Particularly difficult noise offenders are flourescent lights and AC motors, if these are on the same line. Also, try different grounding schemes and BE CAREFUL!
Subject:RE: wireless mic buzz Reply by: rraud Date:6/18/2002 7:46:01 PM I think the occational buzz our friend is experiencing is a momentary weak RF signal, or interference, usually occuring with lower priced non-diversity wireless systems, but not exclusivly of coarse. Unfortunatly it's almost impossible to remove these spits and buzzes ounce they're recorded. If it were a constant electro-magnetic or ground hum the NR plug-in could be employed to attenuate it. If you have any control over the recording, the only simple advice I can offer is, in the future, keep the reciever and/or antennea away from walls, metal objects and in LINE-OF-SIGHT and close to the talent. (I'm amased at how many receivers (w)integral antennas I find in back-rooms and enclosed metal racks.) Also adjust the input gain on the transmitter so it's sending out a strong signal... but not distorting. If it has muliple frequency channels, try another. Sorry I'm not much help on your immeadiate problem.

Subject:wireless mic buzz

Posted by: BobCole

Date:6/18/2002 1:09:10 PM

Have Sound Forge 4.5a. Frequently have to deal with voice recordings from wireless mic, which have occasional buzz right over important dialog.

Is there a setting to mitigate this buzz? Noise Reduction only works somewhat (and for the buzz over the words, I don't want to use it at all). I have looked at Spectrum Analysis but cannot figure out where to go with its data.

Related question: the recording path was:

wireless mic into p.a. system.
Channel 1 of recording was hardwired directly from p.a. system. This line has the bad buzz. Channel 2 of recording was a camera mic recording the speakers of the p.a. system.

Channel 2 doesn't have any buzz at all. Audio is not as crisp, but clearly the p.a. system has a cheap chip that strips out wireless mic buzz. Do you agree? Can I use a similar process via Sound Forge?

-- BC

Subject:RE: wireless mic buzz

Reply by: Chienworks

Date:6/18/2002 2:18:33 PM

That buzz is often interference from AC line current, which is 60Hz. The sound system may have a 60Hz (and 120Hz & 240Hz for overtones) notch filter built in to help reject that hum. You can try using EQ to notch out 60, 120, and 240Hz. If you're only using Sound Forge XP, you won't have the ability to filter narrow notches though. The EQ curve filter is only available with the full version of Sound Forge.

Subject:RE: wireless mic buzz

Reply by: havlicek

Date:6/18/2002 3:35:54 PM

Try using wires...balanced lines are important for that very reason. I forget the exact electrical explanation, but it's something like: you get the buzz on both "sides" (balanced cables are 3 conductor XLR or TRS 1/4") of the cables but 180 deg. out of phase so they cancel each other out. Wireless mics are nothing less than a radio transmitter so it should be no surprise that they can pick up line noise. Particularly difficult noise offenders are flourescent lights and AC motors, if these are on the same line. Also, try different grounding schemes and BE CAREFUL!

Subject:RE: wireless mic buzz

Reply by: rraud

Date:6/18/2002 7:46:01 PM

I think the occational buzz our friend is experiencing is a momentary weak RF signal, or interference, usually occuring with lower priced non-diversity wireless systems, but not exclusivly of coarse. Unfortunatly it's almost impossible to remove these spits and buzzes ounce they're recorded. If it were a constant electro-magnetic or ground hum the NR plug-in could be employed to attenuate it.
If you have any control over the recording, the only simple advice I can offer is, in the future, keep the reciever and/or antennea away from walls, metal objects and in LINE-OF-SIGHT and close to the talent. (I'm amased at how many receivers (w)integral antennas I find in back-rooms and enclosed metal racks.) Also adjust the input gain on the transmitter so it's sending out a strong signal... but not distorting. If it has muliple frequency channels, try another.
Sorry I'm not much help on your immeadiate problem.