a PA/ Amp question

[mward69]

I'm not a big tech guy, but know this doesn't seem right. Our band PA consists of peavey SP-4 mid highs with 2 15's and Peavey SP 118s subs. the rack has all peavey amps with comp/gate, crossover, vocal effects etc...
Here is the problem.....
The 18's {which are 8 ohms} are running off a 2500 watt amp wired bridge mono, we don't really push it that hard, I noticed our singer {his gear} had the gain knob MAXED out. every time the amp started clipping, it would cut out, I was the blame {always the bass player}
I finally turned it down to the 2 'o clock position. haven't had any cutouts since, but did noticed the 18's are sounding bad. My bass sounds like a syth now, the kick drum sounds distorted. My 1st thought was that they are blown....any input from you techie folks would be much appreciated.

 

[will33]

Which gain knob are you talking about being maxed, the one on the bass or kick mixer channels, output on the crossover, knobs on the actual power amp? The only thing that should be cranked is the knobs on the power amps but you have to watch what you feed them. Have you listened to each sub independently? Perhaps one is blown, or they may be wired out of phase. Proper placement of subwoofers is important too, set them up the wrong way and they'll cancel each other out at some frequencies. If this is what's happening and he doesn't know it, it'll cause him to keep turning them up looking for sound that he's not going to get.

 

[Munjibunga]

If it's the gain knobs on the power amp, their function is to control the input sensitivity of the amp. Even at 2 o'clock, the amps can be driven to full power, but it will take a higher input voltage to do it. It sounds like you were probably overdriving the amp and possibly distorting the speakers. They may have been damaged by this, hence, the apparently blown speaker(s).

 

[mward69]

Yeah, sorry, the gain on the amps was at full. I always thought you brought it up till you start seeing the clip light, then back it down a bit. the subs are "piggy backed" NO one in the band are "sound guys" so everyone has their own belief on the way it should be setup. I have told my singer that I would sacrifice some $$ from a gig to hire a pro to come out and tweak the system. Sounding like crap because of band performance is one thing, sounding bad when you have a fairly new and expensive PA is a whole new can of worms. Our singer ge's more money since it is HIS PA and monitors, they way I see it, the PA is PAID for....so maintain it..

 

[A9X]

Not sure what's wrong, but here's some info you may find useful.
http://www.talkbass.com/forum/showthread.php?t=362612&goto=newpost

 

[yamaha]

Many possibilities.

If some of the band members are reluctant to seek professionnal help ($), then I've played clubs where the DJ/Board guy is a real pro, but sometimes just a fader tweaker. You may also have friends of friends, or family, etc..., that are competent in the PA department.

As stated before, many gain settings to check, phase, and individual components.

Sorry I coulden't help you more. However, next time you gig in Montreal, let me know, I can probably stop by and give you a hand.

 

[billfitzmaurice]

, but did noticed the 18's are sounding bad... My 1st thought was that they are blown....

Could be, if you don't have your amps brickwall limited to prevent over-voltage it's very easy to fry them. 99% of the time toasted subs is the result of improper placement, and if you've got them on either side of the stage that's improper. This thead explains why:
http://billfitzmaurice.com/phpBB2/viewtopic.php?t=398

BTW, the most important investment isn't the thousands of $ in amps and speakers, it's the $34.95 to learn how to use them.
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