Jump to content

Explain this high pitched sound.


Recommended Posts

  • Members

Hi All, Splain this one. I am looking for a reason this sound was being produced.

Outdoor street festival, band on a flatbed trailer as a stage, classic rock genre, audience size about 200. 5 piece Bass,Drums, Guitar X2, female VOX X3 - no keyboard. FOH is Bose speakers on sticks on top of Subs in front of stage L and R.( not the PA1 things). Normal wedge monitors on stage.

As I walk up from behind ("back stage") this super high feedback type tone hits me. It's way up there around 18Khz. I check out he band, enjoying the performance walking around in front trying to see what is making this sine wave sound that is now even louder in front. No keyboard at all. The tone is higher than the highest note on a guitar. It stays at a consistent volume level as the dynamics of the band change. I could not find FOH sound person. If they had a tablet walking around I could not find him/her. The band was good and put on a quality show. They had modern equipment not hobbled together jam session gear.

I still can't figure out where this sound was coming from. Any thoughts to solve the mystery?

Link to comment
Share on other sites

  • CMS Author

Are you sure it was that high? (18kHz) That's at the upper limit of most SR gear, and I'm fairly certain nothing Bose sells would reproduce it....the Panaray 802 series III is 10dB down at 15kHz.

 

You didn't state you age or that of the band or majority of the audience...Ironically, if you're younger, and they're older, it's entirely possible they didn't hear it at all...I know at 54 my upper limit is about 12kHz.

 

Regarding the "what" part of this, my first guess would be a component failure somewhere in someone's gear was sending that signal...or not filtering it.

Link to comment
Share on other sites

  • Members

Thanks for the response Craig. No, I'm not sure it was 18K. It was just way higher frequency than any notes being played or sung, Much higher than typical mike feedback. As far as age goes the band looked to be late twenties. The audience was children up to old folks around 60. As my fifty year old ears heard this I said "Wow" out loud to my forty year old date and she knew what I was commenting on.

After looking at a picture of the Panaray 802 I can confirm that was the mains being used.

I am just curios in an audio geek sort of way to identify what was generating this tone.

Link to comment
Share on other sites

  • Members

I had a band mate once who had a pair of Behringer B215D speakers. They would whine around 10kHz whenever they weren't plugged into the same power bar as the mixer. I attributed this to poor power supply design. The owner didn't care, he was well over 60. :)

Link to comment
Share on other sites

  • Members

I recall experiencing this phenomenon as described. The cause was the negative speaker outputs of two different amplifiers were tied together... due to shorted together pins 1- and 2- on a Speakon NL4 patchbay running bi-amped monitors.

Link to comment
Share on other sites

  • Members

I've once experienced guitar rig that had high pitch whine when he stop playing it wasn't guitar feedback either just unusual high pitch sound when he stop playing. Which i made him aware of it but just shrug it off so what. Although drove a lot people nuts. So use the mute button when he stop playing. Also had active sub that use to oscillate low frequency before it finally took a dump.

 

Link to comment
Share on other sites

  • Members

I've heard a similar sound in two instances; one was an effects processor receiving a signal from and aux send and being returned to board channel with that same aux on the return channel not quite turned down all the way. The other time was an extremely hot channel turned down cross talking into an adjacent channel.

Link to comment
Share on other sites

  • Members

I had an interesting experience at an outdoor festival this past weekend. There were times of what sounded like sustained feedback - which surprised me because the FOH guy, who was also doing the monitor mixes, was on the ball and normally would have caught it right away.

 

The problem disappeared when an FM radio transmitter, which was being used to broadcast the event locally, was switched off.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...