Clipping or Too Much Power?
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cgutz
AK Member
I bought my Jensen 24 speakers in 1977 from a guy who powered them with 250wpc. They are rated for 75watts. He never had any problem cranking them up. I only had 50wpc but you could hear them strain in clipping. I really think too little power was worse than too much power, as long as it is clean power.
Fyi - the speakers, refoamed and recapped are still in use on my tube amp.
Fyi - the speakers, refoamed and recapped are still in use on my tube amp.
This should be interesting.
I think my opinion on this topic is fairly well known, as I've been saying it since I joined the site. However, this is a topic that will never get resolved since many have certain opinions so ingrained in them that no amount of proof to the contrary will ever change their minds.
It seems prudent to assume both phenomena can kill your speakers.
I am learning that I'm not really pushing the higher wattage constantly...primarily it's on the transient highs and lows. Seems generally that decent speakers can handle clean transients..and that's the key...clean transients...dynamic headroom...from higher wattage amps where the peaks stay within their power zone. If the volume on a low wattage amp is turned up too high those same peaks exceed it's amplification capabilities, and the signal clips. What physically happens at the speaker, as a result of the clipping, is yet to be made clear to me.
Of course, everything in moderation as there's other forces in the universe that might melt your coil due to heat generated from too much current forced through it...or over excursion of the speaker.
I suggest both schools are right...and I've had too many shots of Jack Daniels to post about stuff I know little about so I gotta go before I say something really stupid....like...this is not a black and white world....oops, too late.
I am learning that I'm not really pushing the higher wattage constantly...primarily it's on the transient highs and lows. Seems generally that decent speakers can handle clean transients..and that's the key...clean transients...dynamic headroom...from higher wattage amps where the peaks stay within their power zone. If the volume on a low wattage amp is turned up too high those same peaks exceed it's amplification capabilities, and the signal clips. What physically happens at the speaker, as a result of the clipping, is yet to be made clear to me.
Of course, everything in moderation as there's other forces in the universe that might melt your coil due to heat generated from too much current forced through it...or over excursion of the speaker.
I suggest both schools are right...and I've had too many shots of Jack Daniels to post about stuff I know little about so I gotta go before I say something really stupid....like...this is not a black and white world....oops, too late.
Blue Shadow
Waiting for Vintage Gear from this century
This is AK, there is NO issues that will be settled once and for all.
In my experience, both.
Depends on how you define power -- too much clean power can overheat speakers and fry them, but I suspect that's a pretty rare occurrence. On the other hand, too much dirty power in the form of distortion can easily take out speakers. Of course that dirty power is a result of not enough clean power leading first to distortion, which lasts much longer than the transient that the distortion is an attempt at reproducing, and then to clipping and even dumping raw AC into the speaker.
But either way, it's power.
But either way, it's power.
ron-c
Addicted Member
Back in the early 1970s McIntosh was making both speakers and amplifiers. These came in a variety of sizes.
After a speaker was engineered and extensively tested it was ready to go to market. A funny thing happened though in that many tweeters and midranges were being replaced under warranty.
This was perplexing in that the speakers were paired with the appropriate amplifier models and some customers were having driver failures and some were not. After some study it was determined that the amplifiers were being overdriven into clipping which was destroying the speakers. When an amplifier is clipped it will be louder as the sound distorts and thickens and the sound frequencies will be harmonically multiplied so that they move up into the higher ranges. This can result in an increase of 40% or more over the amplifier's rated clean power. In one sense the speaker is damaged by to much power due to this increase.
So McIntosh developed the Power Guard circuit that limited the loudest peaks to 2% or so distortion. The result was the amplifiers with Power Guard dramatically reduced driver damage even though they were twice as powerful as the preceding model that could destroy speakers when clipped.
Sonic ally there was the secondary issue of a lack of clarity when playing complex music such as orchestra or large choral pieces. In this case the popular 70 watt amps were found to be clipping peaks at perceived lower volumes. Once again Power Guard would solve this problem and restore clarity.
If the audio signal is clean it may not sound as 'loud' as a distorted signal but a sound pressure reading may show the undistorted amplifier to actually be louder. The distorted signal will be denser as it is filled with side bands of distortion which is not a goal of a high quality system.
Thanks,
Ron-C
After a speaker was engineered and extensively tested it was ready to go to market. A funny thing happened though in that many tweeters and midranges were being replaced under warranty.
This was perplexing in that the speakers were paired with the appropriate amplifier models and some customers were having driver failures and some were not. After some study it was determined that the amplifiers were being overdriven into clipping which was destroying the speakers. When an amplifier is clipped it will be louder as the sound distorts and thickens and the sound frequencies will be harmonically multiplied so that they move up into the higher ranges. This can result in an increase of 40% or more over the amplifier's rated clean power. In one sense the speaker is damaged by to much power due to this increase.
So McIntosh developed the Power Guard circuit that limited the loudest peaks to 2% or so distortion. The result was the amplifiers with Power Guard dramatically reduced driver damage even though they were twice as powerful as the preceding model that could destroy speakers when clipped.
Sonic ally there was the secondary issue of a lack of clarity when playing complex music such as orchestra or large choral pieces. In this case the popular 70 watt amps were found to be clipping peaks at perceived lower volumes. Once again Power Guard would solve this problem and restore clarity.
If the audio signal is clean it may not sound as 'loud' as a distorted signal but a sound pressure reading may show the undistorted amplifier to actually be louder. The distorted signal will be denser as it is filled with side bands of distortion which is not a goal of a high quality system.
Thanks,
Ron-C
davidro
Lunatic Member
Well unlike some other subjects which inherently involve subjective views (e.g. cables etc) I would have thought this topic should be straight forward - which really blows speakers?
My layman's understanding:
When an amplifier is Underpowering (clipping) it means the transistors are flat out open and pumping out DC voltage to the speakers constantly. In normal regime they open and close but if the amp clips they stay open. If the constant DC voltage is high and lasts long enough it will cook the voice coils.
Overpowering speakers with too powerful amplifier means the amp is sending short but too large bursts of DC voltage (normal regime, opening/closing) to the speakers and eventually the voice coil overheats, cooks and speakers die.
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noogies
My Favorite Woofers.
I would posit that it's perfectly okay to power speakers rated for 75 WPC with 250 watts, as long as you don't twist off to the point of feeding those speakers significantly more than 75 of the available 250 watts. If you exceed the rated power input you can reduce the speakers to smoking ruins pretty quick.
Conversely, if you run a pair of speakers whose minimum power requirement is, say 50 WPC with an amp whose output is perhaps 15 WPC, clipping (or square-waving) can turn your tweeters into raspberry jam if you crank it up.
An oversimplification, I know, but speaker manufacturers put power requirements/limits on their products for a reason -- the speakers are sold with warranties. If you couldn't blow up a speaker by either over- or underdriving it, the manufacturer wouldn't bother putting a minimum AND maximum power rating on it.
Oh, and by the bye, I've personally seen speakers blown up both ways.
Conversely, if you run a pair of speakers whose minimum power requirement is, say 50 WPC with an amp whose output is perhaps 15 WPC, clipping (or square-waving) can turn your tweeters into raspberry jam if you crank it up.
An oversimplification, I know, but speaker manufacturers put power requirements/limits on their products for a reason -- the speakers are sold with warranties. If you couldn't blow up a speaker by either over- or underdriving it, the manufacturer wouldn't bother putting a minimum AND maximum power rating on it.
Oh, and by the bye, I've personally seen speakers blown up both ways.
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Audio signals are AC , not DC brother.:nono:
I know. I was being explained trannies chuck out DC when they choke. Wrong?
No, that's a myth. If an amplifier has not failed, it will not send DC no matter how much it's being clipped.
How does overpowering and underpowering kill speakers? In laymans terms for us noobs.
Well, I don't believe it's possible to damage a speaker from under powering it, but as far as over powering a speaker, either excursion limits are exceeded or thermal limits are. Speaker can only move so far and can only dissipate so much heat. Over powering a speaker to the point of damage exceeded one or both of those. It's not DC and it's not clipping, it's a thermal or excursion issue.
I have a theory as to why smaller amps seem to be responsible for more tweeter deaths, but it still ends up being an over powering problem, and not related to clipping, although clipping is probably present when it happens. I do not have the test equipment to prove my theory, but I believe it's likely to be the case of damage.
I thought he meant output transistors.:scratch2:
Whats the theory? We are eager minds willing to learn in this thread.
You are both wrong.