ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  
Pages: [1] 2  All   Go Down

Author Topic: 6 Blown Woofers + fuses - how to protect them?  (Read 4329 times)

Brad Worrell

  • Newbie
  • *
  • Offline Offline
  • Posts: 12
    • http://soundwag.com
6 Blown Woofers + fuses - how to protect them?
« on: July 11, 2008, 02:10:43 pm »

I did an install in a bar here in NYC where I installed 12 JBL Control 28's on 3 Crown Power amps, everything properly matched. Recently all six speakers, which were all the "left" speaker channel - across all three power amps, blew out. I got the crossover fuses replaced (which is what it always is with these Control 28's) only to find that the woofers in all six enclosures were also blown.

My questions:

1) What could cause such a blowout across three amps, only on one side, and take out the crossover fuse AND the woofer?

2) How can I protect against this in the future? Is there any kind of "speaker surge protector" or a resetable fuse system?

This place only plays iPods and audio from the TV (sports events) via a zone mixer. No DJ's, no karioke. The speakers had been up for maybe two years, old age? What's the life expectancy of a well used cone? I've put in cheap limiter/compressors in places that use DJ's, but none of these businesses ever want to fork over for expensive protection like the Drawmer SP2120 or a Driverack.
Logged

Craig Hauber

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 580
    • http://www.csaproductionsinc.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #1 on: July 11, 2008, 02:37:56 pm »

Is the fuse just for the tweeter?

iPods can get really loud if someone has it turned up for a quite song and then the next song jumps way loud.

Also check the activities of the after-hours crew.  I was servicing video at a restaurant once and witnessed the clean-up crew nonchalantly walk over and slam all volumes to max (like it was normal everyday procedure for them) -Never understood why mariachi has to be played so loud!
The restaurant management was always perplexed why the audio system was always breaking down when they just played light jazz really quietly all the time

I would suggest a limiter of some kind.  Either a dsp or even something as simple as a 4-channel dbx compressor to handle L&R from both input sources -with a security cover of course.


Logged
Craig Hauber
CSA Productions Inc.
Ventura-Santa Barbara CA
www.csaproductionsinc.com

Duane Massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2189
    • http://www.ozknozz.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #2 on: July 11, 2008, 09:56:11 pm »

The fuse is inline with the input, and must be soldered in. The woofers in these boxes can fail if the program gets a little too aggressive or someone pops in a tune with lots of real low-freq stuff.

I would put in both a limiter and a hi-pass filter, and set the filter at 50hz for starters.

BBE makes a processor that is cheap and may do what you need.
Logged
Duane Massey
Houston, Texas, USA

Dick Rees

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 6592
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #3 on: July 11, 2008, 10:22:06 pm »

Duane Massey wrote on Fri, 11 July 2008 20:56


I would put in both a limiter and a hi-pass filter, and set the filter at 50hz for starters.

.



I'd set the HPF higher as these boxes are specced out at 60Hz on the low end.
Logged
 Neo-Luddite, Rocket Surgeon
"Pay no attention to the man behind the curtain."

Duane Massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2189
    • http://www.ozknozz.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #4 on: July 12, 2008, 11:54:22 pm »

Dick, you're probably right; should've looked up the specs instead of relying on my very suspect memory....
Logged
Duane Massey
Houston, Texas, USA

Don Boomer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1034
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #5 on: July 14, 2008, 10:47:58 am »

BradGoop wrote on Fri, 11 July 2008 13:10


everything properly matched.




What exactly doe that mean?
Logged
Don Boomer
Wireless Sales Engineer
Line 6, inc.

Brad Worrell

  • Newbie
  • *
  • Offline Offline
  • Posts: 12
    • http://soundwag.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #6 on: July 14, 2008, 04:35:29 pm »

Don Boomer wrote on Mon, 14 July 2008 10:47

BradGoop wrote on Fri, 11 July 2008 13:10


everything properly matched.




What exactly doe that mean?



Ohms, watts & wiring.

It means nothing is over or underpowered.
Logged

Brad Weber

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2477
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #7 on: July 15, 2008, 09:15:06 am »

Don may have been getting at that you did not identified the amplifier model or whether they are run stereo, parallel or bridged, whether it is two speakers on each channel, etc.  Beyond that, it is not clear whether any limiting or other processing such as a high pass filter is involved and their settings, whether the amp inputs are wired parallel between all three amps or if they get separate feeds and so forth.  Are the iPod and TV source permanently wired to the mixer?  Is the system run stereo or mono?

Outside the system, was there any specific event potentially related to this?  Perhaps something like somebody connecting their iPod with the input and system turned up?  Was there a power outage or any other problems with other equipment?
Logged
Brad Weber
muse Audio Video

Brad Worrell

  • Newbie
  • *
  • Offline Offline
  • Posts: 12
    • http://soundwag.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #8 on: July 15, 2008, 10:40:31 am »

It's all stereo, with individual outs from an SZone mixer. No limiting or protection in-line, although power for everything is run through two Furmans.

There is a automatic switcher in the iPod line-input, for a juke box. It's a device that I'm a bit horrified by but they insisted on it. As far as connecting the iPod or power outages. This is stuff that I have no knowledge of or control over, which is kind of the root of my post. My first guess was that someone had plugged in an iPod with the gain way up. It seemed like one of the only ways that one side could get such a massive surge while the other was untouched. So, could that be it and what can I do to protect from that in the future? It doesn't seem to me, that a limiter of any sort will protect from that, will it?
Logged

Duane Massey

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2189
    • http://www.ozknozz.com
Re: 6 Blown Woofers + fuses - how to protect them?
« Reply #9 on: July 15, 2008, 08:49:23 pm »

IF you set up the limiter properly it will give you a good chance of protection from "oops!", and a hi-pass filter will keep the sub-freqs out that can show up on some types of music.
Logged
Duane Massey
Houston, Texas, USA
Pages: [1] 2  All   Go Up
 

Page created in 0.067 seconds with 18 queries.