Speaker compatibility

wuzzo

668- the neighbour of the beast
Hello-

I've been using a pair of passive Peavey speakers in a PA system- 8 Ohms - Peavey amp rated at 150 watts per channel into 8 Ohms.

Now I have a larger mixer rated at 300 watts per channel into 8 Ohms. I'm never going to be cranking the mixer up full so- can I get away with using the Peavey speakers ?
 
It does rather depend on what their rating is. Model number might help. If the 150W amp coped, then I'd simply give them a go. Speakers usually sound horrible well before they get damaged. If you are in control of the volume, all should be fine. Many folk always use amps with more power than the speakers are rated at, and then keep levels down. Quite normal. Rather like the old analogy of a big engine in a small car - if you stick to the speed limit, you just do the same job more smoothly with less effort. Foot down flat out could be a problem.
 
As Rob says, without the details of the speakers we can't give you a firm answer. Similarly, what are the amp power ratings? Peak? RMS? Something else?

However, depending what reading it is, 300W, let alone 150W, is pretty low for most PA speakers.

Second, there's a rule of thumb for PA specs that you should use an amp rated around double the speaker's maximum then let it loaf along so you get a signal with less distortion or noise.
 
It does rather depend on what their rating is. Model number might help. If the 150W amp coped, then I'd simply give them a go. Speakers usually sound horrible well before they get damaged. If you are in control of the volume, all should be fine. Many folk always use amps with more power than the speakers are rated at, and then keep levels down. Quite normal. Rather like the old analogy of a big engine in a small car - if you stick to the speed limit, you just do the same job more smoothly with less effort. Foot down flat out could be a problem.

Thanks for that , rob- reassuring. The speakers are Peavey Eurosys 2 -product # 15005660- good solid jobs. I don't have six hundred quid to spare for a new pair.
The new powered mixer is a Behringer PMP6000
http://www.musiciansfriend.com/pro-audio/behringer-europower-pmp6000-20-channel-powered-mixer

Thank you, bobbsy.
 
If you run them at about the same volume you'll be giving them about the same power regardless of the amp's rating. The only real risk is that feedback or a pop through the system may push the speakers harder than before.
 
Try to think of just getting the same SPL level as with the 150-watt amp. However, you didn't say what the speakers power rating is ?

I'm sitting in front of speakers rated for 45-watts, but driving them with a 85-watt amp. Who cares : )
 
Try to think of just getting the same SPL level as with the 150-watt amp. However, you didn't say what the speakers power rating is ?

I'm sitting in front of speakers rated for 45-watts, but driving them with a 85-watt amp. Who cares : )

Well- I can't find any specs. for them. I think they're elderly- and Google ain't what it used to be.
 
I always use more amp power than the speaker rating, this is because the thing that blows speakers more than anything is amps square waving because they run out of power.

When a speaker is over powered it lets you know very quickly by the crap quality of sound coming out. Where by an amp is square waving may just be doing this by occasional clipping and it will slowly be stuffing the speakers without you noticing the distortion because it is not happening all the time.

Alan.
 
What Alan says ^^^

"If you can prevent the power amp from clipping (by using a limiter), use a power amp that supplies 2 to 4 times the speakers continuous power rating per channel. This allows 3 to 6 dB of headroom for peaks in the audio signal. Speakers are built to handle those short-term peaks. If you can['t keep the power amp from clipping (say, you have no limiter and the system is overdriven or goes into feedback) the amplifier power should equal the speakers continuous power rating. That way the speaker wont be damaged if the amp clips by overdriving its input. In this case there is no headroom for peaks, so you'll have to drive the speaker at less than its full rated power if you want to avoid distortion."


How Much Amplifier Power Do I Need? | Crown Audio - Professional Power Amplifiers
 
Well......I'm baffled. I can't get a peep out of this new mixer.
I'm inputting passive guitar, two passive speakers connected correctly, faders, knobs set as suggested, all the unit indicator lights work as expected- no sound.
Dimwit user or faulty mixer ?
 
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Check to make sure the 'standby' switch isn't pushed in - it mutes all the input channels except the CD input.
 
What a mug ! Dead guitar lead. I ALWAYS check that first, but............
Thanks for your input- much appreciated and I'm sorry to have wasted your time.

On the upside- the mixer runs very quietly and seems to have enough punch for the band . I'm looking forward to adding the other instruments for a better evaluation. The Peavey speakers sound good.
Thanks again.
 
it is not often I disagree with the worthies at HR but I do not subscribe to the well trodden myth that PA speakers should be linked up to an amplifier of twice their power rating because of "square wave burnout" . If an amplifier is driven into clipping and puts a high level of HF into a speaker it does not matter if it is a 150W amp or a 300W amp, the latter only produces 3dB more level and so audible clipping will be no easier to detect, especially since you will by that time be deaf due to the 115dB SPL! (for a speaker of 90dB/W sensitivity) .

There IS a case for rather more power than the speaker rating and that is in a home hi fi system where you are actually listening attentively to the music. You want the power reserve for peaks and, as someone said, speaker are good at handling such peaks. What they don't like is continuous overload because the common failure mode is VC burn out not excessive cone displacement (but DON'T put bass git thru' thru your home hi fi!)

Where there is a system that cannot be closely monitored the speakers should, IMHO be well above the drive amp rating but said amp SHOULD NOT BE OVERDRIVEN.

This power ratio myth is also bandied about for guitar speakers.."Need to move that air daddyo!" Bollox. For any guitar amp the speaker should be rated at least 50% higher than amp power. For valve amps I prefer to see 100% because most valve OP stages can deliver 25% above rating and many a good 100%. Then, not ALL guitar speakers are as conservatively rated as our Celestion friends products.

The OP CAN use a 300W amp on 150W speakers so long as he is in the room with them. Leave the system in the care of some mutton jeff DJ and there will be a nasty smell in short order.

Dave.
 
You can use a 10,000 watt amp on a 5 watt speaker as long as the speaker can get loud enough for whatever purpose you have in mind. You can use a 5 watt amp on a 10,000 watt speaker and you'll never damage the speaker, even if that means driving the amp into full square wave at the output and two or three times its rated power.

Speakers fail for thermal or mechanical reasons. Thermally, it's all about the area under the curve, a.k.a. watts, a.k.a. heat, plus time. The shape of the waveform has nothing to do with it. Mechanical failure comes from excess voltage.
 
Pro amps have some funky rating system. I can see it as useful, though, since no one cares what it sounds like !
 
The speakers will be fine. No problem. No concern. No debate.

This rating isn't a weight limit or a speed zone, this is power (heat) rating. Permanent damage comes from physical abuse (heat, over-travel, etc.) and not academic numbers. You would actually have to try diligently to damage these speakers in this setup and you wouldn't like the sound during the process.

Peavey. They sound okay, but not all THAT great in the first place. Overdriving them won't make your life any better -- and they'll tell you along the way.


Ponder5
 
I'm with Bouldersoundguy. The amp/speaker combination should work and Peavey make speakers that can be work horses but never sound great.

I'm HALF with ecc83 on the "double the power, no square waves" thing. I stand by my "double the power" advice and, although avoiding clipping is a small part of it, I have other reasons for advocating that.

There are a lot of people who will tell you to always run you amp flat out and control levels on the mixer. I don't like this. Turn your amp up all the way and even on an expensive system you will start to get a bit of hiss. Turning the amp down and the hiss magically disappears. Also, I much prefer to operate with a gain structure such that the input pots, faders, meters, and master aren't at two high or low a level. Mixing is much easier if your faders are up near zero rather than trying to make fine adjustments in the bottom half inch of travel. What I tend to do is set up the mixer with the amp turned all the way down, then gradually turn up the amp while play something that has my faders where I want them and the meters bouncing into the yellow occasionally. So long as you're not in a venue that needs a bigger system than you have, you shouldn't have to turn up the amp much beyond half way or so to get the levels you need, especially if the amp is around double the rated power of the speakers.

It's worth remembering that the level control on an amp does nothing to the output power--you're attenuating the input so if you have a single loud transient it'll still get the amplification you need.

Of course I'm not talking about heavy metal type stuff where distortion is part of the sound. That's not part of my game.
 
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