How much headroom is safe?

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T

The Wizard Of OZ

Well-Known DJ
Dec 13, 2007
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Tampa Bay Area
Hopothetical question. Can you blow a speaker just by connecting it to a powerful amp? Let's say you have an 8ohm speaker like a Yamaha S115V with 250/500/1,000 rating and you have an amp with 1,000 w per channel at 8ohms.

Do you have to crank it up loud before you cause damage or can you operate a speaker on an amp with way more power than the speaker is rated at and playing at moderate volume levels without causing damage?

Simplified question, if you have an amp with three or four times the rated RMS power of the speaker are you going to blow the drivers?
 
That's what I just asked. Using an amp with two or three times the power rating of a speaker. Will it damage the speaker? Will it only damage the speaker if I crank it up loud? Will running speakers on a high power amp at moderate levels damage the speaker? Does a speaker get massive amounts of power from a really powerful amp whether you crank it up loud or not?
 
There are 3 ways I know of to blow a speaker...
1. Over excursion - Happens when the coil forces the speaker in and out too fare, the speaker bottoms out or slides out of its "Tracks" and damages the speaker
2. Over Current - When the speaker has too much current going through it... If a coil is only made for 5A, and you put 10 though, you start to melt the insolation on the coil. This causes shorts between the windings, which changes your resistance and the dynamics of the speaker... and has a good chance of killing your amp...
3. Over compression... This is where you blow the surround off of your speaker, sometimes the dustcap...

I guess to answer your question, #1 and #2 apply, If you over power it, and you are dropping heavy base, you risk over extension... and if you are powering it with more power, you risk damaging the coil insulation. So now not only should you be worried about your speakers, you should worry about your amp...

I Hope that answered your question

EDIT: Re read your question, My answer is, Yes you can use a higher rated amp, but if you crank your gain, you do risk damaging your speakers... When I do sub installs in cars, I sit down with my multi meter to ensure that the gain is set so that I do not over load the speakers... You just go to be careful on how high you hit your gain knob...
 
Let me see if I can assist with this. :)

Using an amp with two or three times the power rating of a speaker. Will it damage the speaker?
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Not necessarily. You will need to be mindful of your levels.
Will it only damage the speaker if I crank it up loud?
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Yes. The amp will not likely be damaged.
Does a speaker get massive amounts of power from a really powerful amp whether you crank it up loud or not?
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No. It could do if you push the input too high.

To fill in a little, high amp headroom is necessary for live sound due to the kick drums and heavy bass. For a DJ company working with program material, it's not as critical. Frequency bands are to be mentioned as well ~ you don't need much if any headroom for the horns. You'll need some for the mids. I recommend double for the lows.

Please bear in mind that amp headroom is a cushion, not a practice. Short bursts of high power output (kick drum) shouldn't cause damage. If you have to push your cabinets past their input power ratings throughout, you need more cabinets. Or more efficient ones at least.

If a cabinet is rated at say 600 watts RMS and you feed it with 1200 WRMS, you could damage the drivers if the amp is fed a hot signal over a period of time. In order to reduce the risk of driver damage, the amp attenuators may be lowered to suit the cabinets you are using.
 
Ok, thank you. Here's why I asked. I got a pair of Bose 601 Series III speakers off ebay for very little money. They were local pick up only and that's why they were only $75 for the pair. I brought them home and I went into my son's bedroom to get his stereo tuner/amp and he had sold it to his buddy. I was going to hook them up to my Yamaha EMX512 powered mixer to make sure everything is OK, but it puts out like 350 WPC @ 8ohms in stereo. I'm not planning to crank them up loud, I just want to see if they work OK before I give the seller positive feedback. I would also like to use them for my singing practice at moderate sound levels, but I don't want to ruin them. I'm in the process of looking for a 100-150 WPC receiver, but until then . . .
 
The guy trying to sell me a pair of them in the late 80s told me they were 450/side and there is no info to refute that claim on the net that I have found....Of course there is no info to prove that claim either. Thats one of the issues I have always had with Bose is the whole specs don't matter thing

Regardless of that it dosen't matter how much headroom you have as long as you are careful you should have no problem. One thing to remember is underpowering a speaker can be as dangerous as overpowering it in the wrong hands
 
For awhile there I thought you were asking about prosound. ;)
 
Well, I was asking from both perspectives. I also have my eye on a very powerful pro amp for my DJ gear. The 601s are for my house, I have 2 EV mains and 2 EV subs for doing events.
 
I hooked up the 601s to my mixer and they didn't blow up. They sound great. Now I need to buy a receiver for them. I was surprised that they could take quite a bit of power.
 
Well let me step in here for just a moment.

I am a big fan of high power.

Speaker ratings at 350/700/1400, is it safe to give this speaker 700 watts? You bet it is that is the least amount of power you want to give it? should you use an amp capable of 1400 watts? This is where it becomes sticky, the answer is yes and you should if you know what you are doing, the problem is too many people DJing don't have a clue as to what they are doing when it comes to sound. The biggest problem here is most will be running the same speaker with 350 watts or less which has a much greater potential to destroy the speaker than an amp capable of 2000 watts.

Yes over excrusion can be a problem at higher powers but it really takes a deaf man not to hear that. But many more speakers are destroyed by people under powering them and then pushing the amps into distortion trying to achieve a higher DB level. Once that amp starts clipping you are producing a square wave frequency signal and your voice coils can actually catch fire with just a few seconds of this.

So is it safe to use more power? The answer is indeed YES, the advantages to this is that the full potential of the speaker can be acheived and still leave you amp headroom for those millisecond peak burst without distortion. The trick is knowing what those levels are!
 
Just to add something to Steve's (Thunder post. For people buying a new amp, don't believe the hype some of them print (2000-5000 watts) the cheap amps use the PMPO rating which is basically BS and end up actually putting 50 watts per channel ;). Stay with a reputable brand that shows the RMS power ratings as well as their bridge output capabilities.
 
I think I may have found the amp I want

That way I can run my mains and subs from one amp. I have total confidence in Yamaha gear as far as quality and reasonably good value. I'm not buying right now, just looking and drooling. If I get that amp, I'll get a Yamaha non powered 12-16 channel mixer too.

With that amp I can run 2 bad ass speakers per side and crank out some serious SPLs. I may not know a lot as far as technical knowledge(I'm learning), but I have a good ear and I know how to operate a mixer. I've helped out on some live sound events with some friends of mine and hope to do more of that kind of thing.
 
Yamaha's are great amps I have a P7000 and I'm very happy with it. Jeff Romard pointed me in that direction and I'll always be grateful. I'm also using the S115V (2 pairs) when I run a single pair I power them with an RMX2450 (500 watts/ch 8 Ohms) when I run both pairs I the use a QSC PLX3102 (1000 watts/Ch 4 Ohms). No complaints, I believe the P3500 will under power the S115V's, for those I'd use the P5000.
 
DJ SVO said:
I believe the P3500 will under power the S115V's, for those I'd use the P5000.
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Jacob beat me to it :sqbiggrin:....Honestly Wiz for the extra hundred bucks the 5000 is well worth the money
 
I hate to burst your bubble but the amp you want doesn't even give a decent amount of power to two of your speakers much less four of them. Using the Yam 3500 for a single Yam 115 per side you would be giving them just 390 watts each, nothing to write home about! using two speakers per side they would be getting less than 300 watts each.

If you are going with the yamaha get the 7000, while it just barely makes the grade for program power on your speakers it will at least allow enough power to hear the music in stereo, and you will need another for the second pair of speakers or subs.

However, the damping factors on these amps don't really impress me at all, while I wouldn't be afraid to use them on the mid-hi in a two or three way setup, I wouldn't like them on the subs.

Look at some other amps such as Crown, Peavey and QSC!

Note: Sorry I didn't even think about the Carvin but I would look at the 2570 instead of the 2000 or Crest (although Crest is now Peavey)

If you really want to get serious with power
 
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