Crutchfield has the audio expertise of the 20 year old kid with a nose ring selling speakers at best buy. I wouldn't call them a reliable source.
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does an amp can be damaged for playing it at the max volume and master?
- Thread starter LeonardoGarza
- Start date
Underpowering myths show up on an almost daily basis. There should be a required reading stickie for everyone, before they're allowed to post. Or something.
Exactly! I like it when the snotty guy who says it quotes big box electronics stores as a way of proving it. But I especially love it when they quote car audio websites as a way of proving it! That's when you get the REAL fun!
BTW, though it IS true that you can blow tweeters by an underpowered clipping amp, cab design has come a very long way, and it's rare that you'll even blow a tweeter in a bass cab these days with mere clipping, since the vast majority of cab designs over the last 20-25 years have addressed that problem. Not saying it can't happen, but it's a lot rarer now than it used to be.
BTW, though it IS true that you can blow tweeters by an underpowered clipping amp, cab design has come a very long way, and it's rare that you'll even blow a tweeter in a bass cab these days with mere clipping, since the vast majority of cab designs over the last 20-25 years have addressed that problem. Not saying it can't happen, but it's a lot rarer now than it used to be.
If I'm not mistaken (and I admit I might be), when using a two way cabinet with a 2nd order hi-pass crossover on the tweeter, if the voice coil in the tweeter melts from thermal overload then the current that would normally be traveling through it will short across the inductor instead, thus greatly lowering the resistance in the circuit (ie. the speaker cabinet). Suddenly, a cabinet which was 8 ohms is now very much less than this and the amplifier which is powering it may be damaged (assuming it doesn't have circuit protection). Is this correct or am I off with this scenario?
So I read this:
[Invalid or Expired Link Removed]
and it says (and billfitzmaurice also posted the same thing) that there is a potential for clipped waveforms to damage High Frequency Drivers
The information from JBL makes sense, but I don't know enough about high frequency drivers to tell: Is this damage thermal or is it mechanical? And in either case is this damage that would result in the type of failure I described above (assuming that scenario is possible, of course)?
So I read this:
[Invalid or Expired Link Removed]
and it says (and billfitzmaurice also posted the same thing) that there is a potential for clipped waveforms to damage High Frequency Drivers
The information from JBL makes sense, but I don't know enough about high frequency drivers to tell: Is this damage thermal or is it mechanical? And in either case is this damage that would result in the type of failure I described above (assuming that scenario is possible, of course)?
billfitzmaurice
Commercial User
- Sep 15, 2004
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- Owner, Bill Fitzmaurice Loudspeaker Design
It is correct, with anything higher than 1st order filtering, although the danger is greatest with 2nd order.
Thermal. A clipped signal has increased high frequency power density, so a tweeter that normally sees x watts with a clean signal may see 10x watts with a clipped signal, toasting it. And yes.
It must be said though that the myth has (or might have) some basis. If clipping itself doesn't damage the speaker, it is also true that, as everyone already said, clipping an amplifier means pushing its power beyond is RMS rating (considering its THD rating as well). It's common to buy amplifiers with a power rating similar to the amplifier's. Although clipping once in a while isn't harmful, constant clipping will mean that the average power is higher than its RMS rating. And I don't really know, now, but common sense would say that in combo amps drivers are chosen with a power rating as close as the amplifier's (since cost is one the main factors, and most people really wouldn't want to distort a SS amp), so clipping a combo might probably mean damaging the speaker. Of course, I'm not saying that the myth is justified, but it's kind of "demonstrated", for the wrong reasons, of course.
Although I can't understand the guitar world, since guitar amps are often overdriven (so, pushed beyond their RMS power rating, I suppose), and by what I remember speakers aren't generally that much more powerful than the amp's RMS power rating. Maybe the standard for tube amps is to declare an RMS power rating with a high THD?
Although I can't understand the guitar world, since guitar amps are often overdriven (so, pushed beyond their RMS power rating, I suppose), and by what I remember speakers aren't generally that much more powerful than the amp's RMS power rating. Maybe the standard for tube amps is to declare an RMS power rating with a high THD?
Not sure, I'll probably be corrected by someone, but I would think that they'd do RMS power for tube amps at full volume, since even in the bass world, that's a sound people sometimes like a lot.
The power rating of an amp is done to some standard (EIA or other). It is to give an idea of the power available from the amp and only to give an idea. Exceeding the "clean RMS" from the amp means very little to the amp. Speaker power ratings are supposed to be thermal power maximums and can mean very little about what the speaker will mechaniclly handle at lower (bass guitar) frequencies. Confused? Most speaker ratings are worthless to bass players. Amp ratings are subject to many variables as well. They are rough guides not absolutes. STOP playing numbers, play music.
They're very very ballpark figures. Generally one shouldn't put a 1500 watt amp through a 200 watt cab, though.
billfitzmaurice
Commercial User
- Sep 15, 2004
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- Owner, Bill Fitzmaurice Loudspeaker Design
In general you're fine if the amp to speaker power ratings are anywhere between 1:2 to 2:1. That's about as good a guestimate possible without knowing engineering details about the speaker that more often than not manufacturers don't make available.
You're right...you will be corrected by someone
RMS refers to clean volume (yes, I know many engineers consider it inaccurate, but it's what we use so what can I tell ya?). When you crank a tube amp into distortion, say an SVT, you go beyond its clean volume and you're going beyond RMS wattage rating as well. Believe it or not, there was a time when the SVT was praised for its enormous amounts of clean headroom. It wasn't till the 90's that tube amps got the reputation for being only for distortion.
Is this to say the ratio shouldn't go lower than 1:2? I regularly run a 5w head into a 240w cab. It seems you just said you shouldn't underpower a speaker
You're right...you will be corrected by someone
RMS refers to clean volume (yes, I know many engineers consider it inaccurate, but it's what we use so what can I tell ya?). When you crank a tube amp into distortion, say an SVT, you go beyond its clean volume and you're going beyond RMS wattage rating as well. Believe it or not, there was a time when the SVT was praised for its enormous amounts of clean headroom. It wasn't till the 90's that tube amps got the reputation for being only for distortion.
I (predictably) stand corrected. So, an SVT's 300 watts RMS rating is at a volume where it's still clean sounding? What would it be if they rated it when it was cranked up all the way?
The SVT came out when most other amps weren't nearly as powerful, right? So, since most amps were tube, and less powerful, they'd break up when not nearly as loud. So that makes sense.
Is this to say the ratio shouldn't go lower than 1:2? I regularly run a 5w head into a 240w cab. It seems you just said you shouldn't underpower a speaker
Why would that be a problem? The speakers don't blow up when the amp is off, do they?
Now you're just being difficult.Is this to say the ratio shouldn't go lower than 1:2? I regularly run a 5w head into a 240w cab. It seems you just said you shouldn't underpower a speaker
Sartori, generally peak power is twice the RMS power, so it would be in the ballpark of 600w, though a spike might even make it higher than that. Wattage is a dynamic thing, not a constant thing. It varies with every note.
Now you're just being difficult.
Sartori, generally peak power is twice the RMS power, so it would be in the ballpark of 600w, though a spike might even make it higher than that. Wattage is a dynamic thing, not a constant thing. It varies with every note.
That's a lot of wattage. Yes, I know it varies with each note played (it would be weird if it was putting out hundreds of watts when you weren't playing anything), but it's still kinda interesting to estimate the total watts.
Because on a tube amp, running out of clean headroom doesn't mean you can't sound good turning up further, just different and maybe not suitable to some kinds of music. I find that my Mesa sounds really cool turned up all the way (but for the sake of my band's ears, not something I'm going to get to do often). It's somewhere between 150-200 watts I think, so turned up full it would be then about 300-400 with peaks higher? Interesting.
Yes, and that's why I am so glad Sansamp invented the VT pedal. Run that thru an SVT and throw some drive on it and it sounds like a cranked SVT at low volumes...pedal of the future!
