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Discussion Starter · #1 ·
I just fried the tweeters out of a pair of Polk R50's, they're rated for 150 watts. was using a new receiver, Pio 1015tx, rated at 120 watts. Volume all the way up (+12) and some rage against the machine and it fried both of them. Any thoughts as to why, just had it up to test what they could do and see how loud it was outside, basically? did I just push them to hard?
 

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Many amplifiers distort heavily when turned up all the way. I believe this called "clipping". You fed this distorted, clipped signal to your speakers and cooked them.
 

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Quote:
Originally Posted by BrownRB
Many amplifiers distort heavily when turned up all the way. I believe this called "clipping". You fed this distorted, clipped signal to your speakers and cooked them.


I thought about giving the (almost certainly correct) clipping/distortion explanation, but then I thought "this guy must be trolling". The question seemed like "I was driving 95 mph in a 55 zone and I got a ticket, any thoughts on why?"


Thank you for being less jaded than me.
 

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Discussion Starter · #5 ·
Well, wasn't ear bleedingly loud though it was fairly damn loud, speakers didn't sound like they were clipping though
 

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Discussion Starter · #6 ·
also didn't seem like I was driving 95 in a 55 if the speakers were rated to handle a higher wattage and it's being fed by a pretty good receiver I was, yes, surprised they blew, and no, I wasn't trolling.
 

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Stick the negative in one side and the positive on the other side of a live electrical socket.


Oh what?


I thought this was how to destroy a speaker. Sorry. :)
 

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Discussion Starter · #8 ·
I'm quickly getting the feeling that I shouldn't have asked and just wandered on in my ignorance.
 

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I won't comment on the intelligence of what you did... Would you try to drive a car rated as capable of 160 mph at 160 mph on the street? I bet you would. Come to think of it, I would have too when I was younger. Live and learn. Best way to learn is by trial and error, if you can afford it.


I don't see anywhere in the Polk literature where the R50 is rated at 150 watts. It just has recommended amplifier power 20 to 150 watts.


Tweeters are generally the first thing to go when a speaker is overpowered with clean power. If the amplifier is driven to clipping you can be pretty sure that the tweeter will go. Tweeters generally can handle less power than the other components of the speaker. For example, the tweeter used in the Klipsch Heritage line speakers is only rated at something on the order of 5W continuous power even though the rated power handling ability of the speakers is much higher.


DC is not generally a problem for tweeters in speakers. There is usually a capacitor in series with the tweeter in the high pass section of the crossover network. In the cheapest speakers, this may even be the entire crossover network.
 

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Discussion Starter · #10 ·
well I would probably drive a car rated at 150 at 120 on the highway, yes, at max volume the speakers still sounded clean not like they were distorting, if I had noticed clipping/distorting I would have turned it right down. Since the receiver was rated at 120 and the speaker specs remmond 20 to 150 I figured it would take 120 okay, obviously I was wrong, I'm curious as to why I was wrong and preferably without the sarcasm, I'm the one paying the price for what I did.
 

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This is not about them being fed to many watts. Its about your reciever not putting out clean watts, clipping and tearing them up.
 

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So. If you want to play your *new* speakers that loud, use the preouts of the receiver to a real amp that can provide adequate clean power to the speakers.


The "rated at" numbers you cite are often unreliable.
 

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Simply put, when you drive an amplifier beyond it's comfortable limits, it actually "squares off" the nice round sine wave that should be the signal to your speakers. This square wave is deadly to tweeters in particular. Chances are if you had a quality 200 watt/channel amp driving your speakers your speakers would have been fine at the same volume.

Overpowering speakers is much healthier for them than underpowering them. And max watt ratings on speakers are generally worthless.
 

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Quote:
Originally Posted by Heck
also didn't seem like I was driving 95 in a 55 if the speakers were rated to handle a higher wattage and it's being fed by a pretty good receiver I was, yes, surprised they blew, and no, I wasn't trolling.
You're more likely to blow speakers with an underpowered amp than an overpower amp. Although this assume you don't just turn the volume all the way up. That's risky no matter what the size of the amp.
 

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Contact Polk, they'll probably send you new tweets. The Rs really aren't meant to be driven that hard. Feeding them more gain won't likely play them louder, just fry them. The 1015 has more than enough power to make the speakers sing as well as they can. If they could benefit from more power, Polk would have rated them up to 200 or 250, like the Rtis and Lsis.
 

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You take an average,at best, receiver and turn the volume all the way up and wonder why speakers get blown? First,with most receivers turning the volume up to the max will send a clipped/distorted signal to the speakers.Never do that.You learned a valuable but expensive lesson.
 

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I just read this thread and developed a question of my own. Is there any way to know how high is too high to turn up any given receiver? At what point does the signal "square off" or at what point do you lose the clean power? I have a Denon 1804 and I think it is rated to 90w per channel in surround mode. My speakers are rated to 100w. Assuming my volume goes from -60 to +12 what should be my cutoff point if the speakers still sound good?
 

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Quote:
Originally Posted by Megalith
I think anything over 0, or close to it, may be asking for trouble.
its about clean power verses reciever distorted power. i have kef q5/q3/q9c rated at only 120 watts and each pair running on its own adcom 200w channel amp and many times i have run over 0db...from +5 to + 15 or so..never any distortion..never any problem. the pioneer's chip amps rated 120 are probably really only 60-70 watts of clean power and may peak at 120 for a second or two. distortion fries speakers.
 
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