A new one on me at DVinfo.net

Steven Davis · May 1st, 2007, 04:40 PM

Well I'd like to say I should have saw this coming, but I didn't. With my Senn G2 100 series, I did a sound check prior to the ceremony, everything was peachy. Well, what I didn't do was take the transmitter close to this 'self powered' speaker the place was using for music. Well, 10 or so feet from when the groom arrived at the front, the mic system just pegged on interference. The buzz was so loud in my ear, I was hearing it in my right headphone.

I didn't even see it coming. I had a lot of back up audio, so I'm fine. But I guess that those self powered speakers transmit some type of frequency.

Just passing along my fun 'extra couple of hours audio editing' lesson. I'll know next time.

Jay Massengill · May 1st, 2007, 06:30 PM

Some self-powered speakers designed for easy PA use also have built-in wireless receivers. All receivers put out weak transmission frequencies as a part of how they operate, but even a regular powered speaker could create interference if something was wrong with it or the cable leading to it. There could be a lot of things near the front of a house of worship that could cause interference though. If you work there again I would do more testing, not just of that speaker, but at any place your wireless might travel during the ceremony.

Steven Davis · May 1st, 2007, 07:06 PM

Yeah, Jay, good advice. I'll do more testing next time I see any equipment.

Seth Bloombaum · May 1st, 2007, 07:14 PM

A standard part of a triple-check-is-everything-right is to have someone walk the entire performance area talking into the mic while you listen on headphones.

It's done all the time for live stage shows and corporate meetings, apparently equally applicable to weddings or any other situation where you have one chance only to get the audio with a wireless.

Jon Fairhurst · May 1st, 2007, 07:17 PM

Are you sure it wasn't a Blackberry or cell phone?

Stephen Murphy has an article in this month's ProAudio Review magazine in which the sound engineer at a live event tells the Blackberry-armed security guard, "Sir! Step away from the console! This is your last warning!"

Jay Massengill · May 1st, 2007, 07:37 PM

I think I'm going to stop telling people that their devices will "interfere" with the audio equipment and instead tell them that since this is special "professional" equipment it will be decoding and recording all their voice mails onto the tape by accident unless they actually turn the device totally off...

Douglas Spotted Eagle · May 1st, 2007, 07:44 PM

Quote:

Originally Posted by Jay Massengill

I think I'm going to stop telling people that their devices will "interfere" with the audio equipment and instead tell them that since this is special "professional" equipment it will be decoding and recording all their voice mails onto the tape by accident unless they actually turn the device totally off...

Since I have an engraver, I think I'll engrave a small plastic plate with a variation of your words....Great way to get them to comply, and will look great right next to the "Talent" and "Suck" knobs.

Ervin Farkas · May 2nd, 2007, 06:54 AM

Quote:

Originally Posted by Jay Massengill

Some self-powered speakers designed for easy PA use also have built-in wireless receivers. All receivers put out weak transmission frequencies as a part of how they operate...

Could you elaborate on this? In 25 years of electronics I have not heard of receivers that transmit...

Thanks,

Mark Holland · May 2nd, 2007, 07:21 AM

Quote:

Originally Posted by Ervin Farkas

Could you elaborate on this? In 25 years of electronics I have not heard of receivers that transmit...

Thanks,

I'd be interested in learning about this too, Ervin!

Steven Davis · May 2nd, 2007, 07:36 AM

Quote:

Originally Posted by Jon Fairhurst

Are you sure it wasn't a Blackberry or cell phone?

I dunno Jon, the interference was centered around the place where the bridal party was which was about 20 feet from the piano and speaker. I supposed it could be a cell, but i have never had interference like I did that day. I'll do a walk a round next time to check all points.

Steve House · May 2nd, 2007, 08:42 AM

Quote:

Originally Posted by Ervin Farkas

Could you elaborate on this? In 25 years of electronics I have not heard of receivers that transmit...

Thanks,

The basic receiver circuit beats a local oscillator with the incoming signal to produce an intermediate frequency which is amplified and filtered before the audio is separated from the RF at the detector stage. Since the local oscillator is an RF generator on its own, it CAN in a poorly shielded enclosure radiate that signal a short distance. It's sort of the same thing you can get when you put a cheap transistor radio on top of your CPU. Well designed receivers shouldn't radiate any substantial amount but the operative word is "well designed" and not all receivers are.

Craig Seeman · May 2nd, 2007, 09:39 AM

Another thing to do is use the Scan feature in the G2. Turn your transmitters off and do a Scan with the receiver. You may need to walk around the place as Seth mentions but you should end up finding a clear channel.

Steven Davis · May 2nd, 2007, 10:32 AM

Thanks to everyone.

Jay Massengill · May 2nd, 2007, 12:44 PM

Exactly as Steve said regarding the weak transmission signals that are generated by radio receivers. That's why historically you weren't supposed to listen to an FM radio while on a commercial jetliner at any time. Of course most current mp3 players have FM receivers built-in, which are probably operative even when you're only listening to mp3's, but oh well...
It's also the reason that scanners pick up their own internal signals on some frequencies and get stuck at that spot unless that frequency is locked out.

May 1st, 2007, 04:40 PM	#1
Steven Davis Inner Circle Join Date: Jun 2004 Location: Richmond, VA Posts: 3,065	A new one on me Well I'd like to say I should have saw this coming, but I didn't. With my Senn G2 100 series, I did a sound check prior to the ceremony, everything was peachy. Well, what I didn't do was take the transmitter close to this 'self powered' speaker the place was using for music. Well, 10 or so feet from when the groom arrived at the front, the mic system just pegged on interference. The buzz was so loud in my ear, I was hearing it in my right headphone. I didn't even see it coming. I had a lot of back up audio, so I'm fine. But I guess that those self powered speakers transmit some type of frequency. Just passing along my fun 'extra couple of hours audio editing' lesson. I'll know next time. __________________ What happens if I push the 'Red' button?

May 1st, 2007, 07:06 PM	#3
Steven Davis Inner Circle Join Date: Jun 2004 Location: Richmond, VA Posts: 3,065	Yeah, Jay, good advice. I'll do more testing next time I see any equipment. __________________ What happens if I push the 'Red' button?

May 1st, 2007, 07:17 PM	#5
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Are you sure it wasn't a Blackberry or cell phone? Stephen Murphy has an article in this month's ProAudio Review magazine in which the sound engineer at a live event tells the Blackberry-armed security guard, "Sir! Step away from the console! This is your last warning!" __________________ Jon Fairhurst

May 2nd, 2007, 10:32 AM	#13
Steven Davis Inner Circle Join Date: Jun 2004 Location: Richmond, VA Posts: 3,065	Thanks to everyone. __________________ What happens if I push the 'Red' button?

May 1st, 2007, 06:30 PM	#2
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	Some self-powered speakers designed for easy PA use also have built-in wireless receivers. All receivers put out weak transmission frequencies as a part of how they operate, but even a regular powered speaker could create interference if something was wrong with it or the cable leading to it. There could be a lot of things near the front of a house of worship that could cause interference though. If you work there again I would do more testing, not just of that speaker, but at any place your wireless might travel during the ceremony.

May 1st, 2007, 07:14 PM	#4
Seth Bloombaum Inner Circle Join Date: Sep 2003 Location: Portland, Oregon Posts: 3,420	A standard part of a triple-check-is-everything-right is to have someone walk the entire performance area talking into the mic while you listen on headphones. It's done all the time for live stage shows and corporate meetings, apparently equally applicable to weddings or any other situation where you have one chance only to get the audio with a wireless.

May 1st, 2007, 07:37 PM	#6
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	I think I'm going to stop telling people that their devices will "interfere" with the audio equipment and instead tell them that since this is special "professional" equipment it will be decoding and recording all their voice mails onto the tape by accident unless they actually turn the device totally off...

May 2nd, 2007, 09:39 AM	#12
Craig Seeman Inner Circle Join Date: Feb 2004 Location: Brooklyn, NY, USA Posts: 3,841	Another thing to do is use the Scan feature in the G2. Turn your transmitters off and do a Scan with the receiver. You may need to walk around the place as Seth mentions but you should end up finding a clear channel.

May 2nd, 2007, 12:44 PM	#14
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	Exactly as Steve said regarding the weak transmission signals that are generated by radio receivers. That's why historically you weren't supposed to listen to an FM radio while on a commercial jetliner at any time. Of course most current mp3 players have FM receivers built-in, which are probably operative even when you're only listening to mp3's, but oh well... It's also the reason that scanners pick up their own internal signals on some frequencies and get stuck at that spot unless that frequency is locked out.