Noise limiter

[Mickeyboro]

Played a wedding gig last night and got cut off eight times, spoiling things somewhat.

I turned down but got quite a lot of the blame from my band members. The light seemed to respond to the A string more than the rest of the spectrum.

What frequencies set off these horrible things and apart from wire cutters how can they be beaten?

[Alien]

Use a long extension lead and plug into another socket. They can't all be on the breaker circuit.

A

[molan]

A lot of the newer ones are tunable so the venue owner can set the frequency range that triggers them

If they've been professionally set up with all electrics running through them then there's little you can do other than working out exactly where the trigger frequency is and trying to cut that on the PA and backline

I have managed to bypass them by taking a power feed from another mains circuit with a very long extension cable though

[MIJ-VI]

[quote name='Mickeyboro' post='911661' date='Aug 1 2010, 03:49 AM']Played a wedding gig last night and got cut off eight times, spoiling things somewhat.

I turned down but got quite a lot of the blame from my band members. [u]The light seemed to respond to the A string more than the rest of the spectrum[/u].

What frequencies set off these horrible things and apart from wire cutters how can they be beaten?[/quote]

Hmm... This may tie in with combating resonant bass frequencies (and their inverse manifestations) aka 'room boom'.

"1/4 wavelength. A wavelength is 1130 (feet per second, the approximate speed of sound at average altitude and humidity) divided by frequency. So 100 Hz has a wavelength of 11.3 feet, 1/4 wavelength of 2.8 feet. The same applies to the distance from a wall in back of the cab, so problem rooms can be fixed with the right cab placement, and made worse with the wrong placement."

- Bill Fitzmaurice

[url="http://www.talkbass.com/forum/showpost.php?p=8901286&postcount=26"]http://www.talkbass.com/forum/showpost.php...mp;postcount=26[/url]

From one of Phil Jones' PJB manuals:

"Often, playing in different venues will cause your bass to sound different. This is partially due to the acoustics of the hall influencing the low frequency waves that are coming from your speaker. Bass waves are large and room dimensions heavily influence them when the walls reflect the sound waves, causing them to collide by adding together or canceling each other out. This causes some fundamental notes (the ones you feel more than hear) to ring out louder than others and some notes not to be heard at all.

Here is an indication of where fundamental bass frequencies are, showing open string's approximate frequencies and acoustic wavelength:

F# string - 24Hz - 46feet
B string - 31Hz - 36feet
E string - 41Hz - 27feet
A string - 55Hz - 20feet
D string - 73Hz - 15feet
G string - 98Hz - 11feet
C string - 130Hz - 9feet

This may give you some indication of the offending notes (frequencies) that may be booming or resonating louder or quieter than others. For example if your speakers are five feet from a wall, the open A string may sound weak. That could be because the path length of the reflected sound off the wall from your speaker is exactly corresponding to half a wavelength on the open A string causing at that particular note to cancel out."

Plan A: try moving the cab around as the first step in combating unusually loud (or dead) bass notes. A walkabout the venue to gauge the results may be useful.

Plan B: if cab relocation fails to adequately tame resonant bass frequencies then a sweepable parametric (or at least semi-parametric, or 1/3 octave graphic) EQ likely will. Listening to how your bass sounds from the point in the room where the noise limiter is located (in a corner which acts like a bass trap?) might be prudent as well.

[JTUK]

The hall/stage is likely to be on one ring and the kitchen, or other rooms on other rings. Bypass the main limited ring.

Or don't take gigs in these places..which is what we tend to do.

[OldGit]

Simple: don't play venues with them fitted. That's our rule.

If a venue has a noise limiter they probably have a damn good reason (and this is not about noise at work for employees). That means that Environmental Health noise guys have been involoved and the venue licence will be under threat.
If you plug in somewhere else with the venue managers OK then he will be risking his licence.

Edited August 1, 2010 by OldGit