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Return to quoting peak wattages?

Apr 11, 2005
127,261
125,194
Plymouth NC
Disclosures
Endorsing: Yamaha, Ampeg, Line 6, EMG
When I first started playing, amp makers would give you the RMS rating and the peak rating of their amps. Maybe it didn't stop people from blowing their speakers, but it did inform newbies that there is a ton of power past the clean rating.

But people balked at the peak rating being quoted because it was often used to make amps sound like they were more powerful than they really were, so eventually the manufacturers dropped it in favor of quoting only RMS, and very few quote peak these days.

Cut to now, where distorted tones are a lot more acceptable, 1000w amps can be had for less than $300, and cabs are getting smaller and smaller. Blown speakers are at epidemic proportions with those rigs. I think a major reason is because newbies don't understand the whole RMS/peak thing. Just today, I saw someone on here say, "My amp puts out 200w, the speaker is rated for 175w, and I thought it was close enough to crank all the way up." Of course, that 200w RMS amp can put out over 400w peak and the 175w rating for the cab is its absolute maximum before the voice coil melts (that's a whole other rant), but how are they supposed to know that if they have no experience with amps and the makers don't inform them?

Therefore, I think the least they could do is educate the consumers a little more than they have been, and one thing that would help a lot is if manufacturers started quoting both RMS and peak wattages again, and explain in the manuals the difference.

Of course, until manufacturers start quoting REAL power handling specs for speakers and not these BS specs that tell only when the voice coil melts, it's still going to happen, but at least newbies would have half a chance to keep from blowing their stuff if they know that turning their amps up all the way can easily result in double or more the RMS wattage. I've brought this up before, and a couple people rejected it, but I don't see what it can hurt as long as they quote both RMS and peak. It would certainly keep some people from blowing their speakers, which in this day and age, should never ever happen.

What say you, the TB cogniscenti?
 
It's more important to talk about speaker ratings in the real sense, because probably 90% of those blown drivers are due to overexcursion. People need to forget those "RMS" themral ratings entirely because that's not what's usually pertinent. Unfortunately, the companies building cabs just aren't likely to come clean in any real way about excursion/xmax/xlim/xmech, and there are so many variables involved, like EQ habits, hidden default voicings of heads and preamps, etc.

But ever since I started playing in bands and doing sound a gazillion years ago bass players have been blowing drivers, so though power has come up, so has driver abilities. I'm not really seeing anything here I wasn't seeing in bands of down at the sound booth.

But the best thing we have now is forums like talkbass that can educate those who actually pay attention. That'll usually happen AFTER they blow some cabs, but that's human nature: to DRFTM*



* DON'T read the freekin' manual
 
It's more important to talk about speaker ratings in the real sense, because probably 90% of those blown drivers are due to overexcursion. People need to forget those "RMS" themral ratings entirely because that's not what's usually pertinent. Unfortunately, the companies building cabs just aren't likely to come clean in any real way about excursion/xmax/xlim/xmech, and there are so many variables involved, like EQ habits, hidden default voicings of heads and preamps, etc.

But ever since I started playing in bands and doing sound a gazillion years ago bass players have been blowing drivers, so though power has come up, so has driver abilities. I'm not really seeing anything here I wasn't seeing in bands of down at the sound booth.

But the best thing we have now is forums like talkbass that can educate those who actually pay attention. That'll usually happen AFTER they blow some cabs, but that's human nature: to DRFTM*

* DON'T read the freekin' manual
Agreed with everything, except for the bit about seeing as many blown bass cabs these days as before. Yes, we do see the same amount, but IMHO, there is absolutely no excuse for it. I could have understood it in the 60's and 70's when the whole monster amp thing was new and bassists used guitar speakers that were woefully inadequate, but now bass amplification has caught up and it's easy to put together a monster bass rig that'll rip your head off that doesn't blow speakers. Personally, I thought it was common sense that a tiny 300w combo couldn't put out the wall of sound an 810 cab can, but apparently it isn't.
 
It's unfortunate but I think it comes down to marketing. Manufacturers don't want to adhere to measurement standards. When you compare two amps with the same power output rating, the one with the more conservative rating might come out sounding a lot better because it is putting out more power. Back when they used to advertise both RMS and peak power, that was probably marketing as well. People would see the peak power rating and think that they were getting more for their investment. The problem is, unless you put the amp on the bench and take your own measurements, you will never know what you're getting.

In terms of blowing speakers, there are the issues that have been mentioned. But what about how the amp is designed? Some amps are well designed, others are marginal because corners are cut in the design and parts specification. The marginal ones can spit smoke and transient spikes which could lead to speaker failure. Maybe this type of failure is less common but you'll never see this sort of thing in a set of specs. Some people buy these amps because they like the sound of an amp that is on the verge of exploding. Case in point, some of the late 50's Fender Deluxe amps.

Here's an interesting tech note that discusses RMS and peak power ([Invalid or Expired Link Removed] ).
 
Since the amp manufacturers are not quoting peak power, is there a formula or something that can determine the peak power if the RMS rating is known?
There is, but if you read David's (beans on toast) linked PDF from Meyer Sound, it's got some complicating things. But generally, you can consider peak wattage to be at least twice that of the RMS wattage rating.
 
It's really not peak wattage that's blowing most drivers anyway - it's speaker overexcursion happening right within the amps' stated RMS spec, and USER ERROR which comes from not listening to how crappy it sounds as the drivers are complaining of their work load, and piling on low EQ that just makes things more likely to take the last train to Fartsville: the Final Version.

But if it makes some of you happy just multiply an amp's honest RMS figure by 2 or 3* ; }



* I use the number 3 because a lot of drivers are running out of xmax by 1/3 their rating ; }
 
It's really not peak wattage that's blowing most drivers anyway - it's speaker overexcursion happening right within the amps' stated RMS spec, and USER ERROR which comes from not listening to how crappy it sounds as the drivers are complaining of their work load, and piling on low EQ that just makes things more likely to take the last train to Fartsville: the Final Version.

But if it makes some of you happy just multiply an amp's honest RMS figure by 2 or 3* ; }



* I use the number 3 because a lot of drivers are running out of xmax by 1/3 their rating ; }

So would it be fair to say that as a general rule speaker overexcursion will occur when you have a cab that is less than 3 times the amps RMS capability?
 
I agree with Jimmy on principle, but I think musicians, in general, owe it to themselves to at least somewhat educate themselves before diving into big complicated bass rigs. I mean, it's not rocket science, and the average joe, (myself included), can easily understand the basics on amp power, speaker handling power, and impedance. Far too many noobs dive in clueless, then come crying when it all blows up in their face. Yes, standardized ratings, and even comparison charts for speaker cabs would be helpful, but unlikely. It's up to the end user to get with the program.
 
i think alot of this was the wonderful information that was put out there about underpowering your speakers and how dangerous that is
or
you must break in your speakers/what?

i learned after using an svt with 4 x 12 sro's, or ever 2 x 12 sro's, and after melting many ev sro and evm's, altecs, and jbl's, and getting on a first name basis with the engineers at ev and jbl
that they recommended the following, that the speaker power rating at rms and the amplifier rating at 2 x rms, gave enough head room to reduce the number of recones on my speakers
so 300/350 Watts rms = 700 Watts, so, speakers = 700 Watts rms

since then, and following those rules, my speaker melting journey has ended
 
Greenboy, what happens when the excursion limited power handling rating is exceed for a sustained period?
You get a ton of posts on here with the title "I just blew my cab."

Ricken, the problem is not only the lack of education with the users, but it's also the fudging of stats, and a ton of really stupid misinformation being put out as fact such as the underpowering myth. I think I explained it really well in another thread last night...if you have 32 oz of water, does it really make sense if someone tells you that you need a 16 oz glass to hold it all? Think of your amp as the water and your cab as the glass, and the underpowering myth really looks ridiculous on its face. But when you have major manufacturers putting out that nonsense (just saw it on SWR's website last week as a matter of fact), people tend to believe it, even though it couldn't be farther from the truth.

So I can't hold the end user 100% responsible. However, I do hold the end user partially responsible for not exercising common sense and diming their amps way past what the cab can take despite signs of potential blowing. And I can hold them responsible for turning up to such ridiculous levels that even arena bands don't turn up to.

Still, it would help greatly if manufacturers would quit trying to paint rosy pictures of their gear that are inaccurate, and be honest about the limits of their gear, especially cabs.
 
"Blown speakers are at epidemic proportions with those rigs"

Really? Epidemic? I'd like to see the stats.
Dude, all you have to do is look at how many "I think I just blew my cab" threads there are in a given week. It's a ridiculous amount, and they're almost all the same thing...big head cranked into tiny cab.
 
So would it be fair to say that as a general rule speaker overexcursion will occur when you have a cab that is less than 3 times the amps RMS capability?

Not necessarily. It's so dependent on EQ habits, the bass's spectrum balance, and hidden default voicing that a lot of heads and preamps have (ie when set "flat" they actually have some EQ stuff goin' on). Some players can really push a cab because they don't have more low frequencies in the final signal than the drivers can actually deal with. But some are just murdering 'em. I see newbies who are into loud styles doing this a lot. They might as well be putting a full-strength sine wave to 'em below cab tuning. It only gets worse with a lot of filter effects, deep flanging, etc.

Then too, some drivers don't have much safe room between xmax, where driver distortion becomes more obvious, to xlim, where the mechanical system is fully to the end of possible travel. Others do though, which means there is a little extra margin for error. That's a know your drivers thing though...

Myself, with the typical bass guitar drivers/enclosure, I'm happy with 1:1 parity, because I won't ignore it the sounds of when the warning burritos are being fired. That parity gives some headroom to anyone who knows how to set their pre and post/final gain, and allows for a variety of EQ styles. But one can easily get all a driver is capable of delivering with less wattage in most cases, or have the potential of 2:1 if they really know what's going on.

...With my fEarful I can easily go twice RMS - even with hot gain upstream - since the drivers' useful excursions are way beyond the driver thermal rating... and even beyond that is a spacious distance to xlim/xmech. That's knowing the drivers, and the type of signal my bass and preamp and effects presents.

Biggest problem for drivers, now as always is User.
 
I'm old school, my ears are trained to RMS wattage. When an amp is 300 watts RMS I have a very good understanding of whereabouts that amp is going lie when it comes to it's output. I've never based any amp I've played thru on peak wattage, rms is what I hear. If I hear a speaker beginning to stress, I back off of the volume or frequency that may be causing the problem, it's that simple with me.
 
I'm old school, my ears are trained to RMS wattage. When an amp is 300 watts RMS I have a very good understanding of whereabouts that amp is going lie when it comes to it's output. I've never based any amp I've played thru on peak wattage, rms is what I hear. If I hear a speaker beginning to stress, I back off of the volume or frequency that may be causing the problem, it's that simple with me.
Agreed, but not everyone is as smart as you or I ;)