miltaryman
Active Member
Made this, because I needed it to understand it: 
Blowing for Dummies
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As far as I know, it always boils down to overpower. Even when the amp is weak and clips, it's still an excess of power that blows the speakers, not the distorted signal itself.
Lower frequencies require more power than higher ones. Consequently, it's in the lower and medium frequencies that clipping occurs first. This causes us to turn up the volume, but since the amp is already out of breath, turning it up has no discernible effect, so we turn it up even more. But although the amp doesn't have enough power to amplify the low and mid frequencies anymore, and it seems to us the volume knob isn't doing much, it can still drive the high frequencies to unsafe levels (unsafe for the speakers, that is). Because most of the musical content is in the middle of the range, and that range isn't increasing in volume, we don't realize that the treble has got to an unsafe level until it's too late and the tweeters let the magic smoke escape.
That's why it's always the tweeters that are killed by clipping, not the woofers.
At least that's how I understand it.
Lower frequencies require more power than higher ones. Consequently, it's in the lower and medium frequencies that clipping occurs first. This causes us to turn up the volume, but since the amp is already out of breath, turning it up has no discernible effect, so we turn it up even more. But although the amp doesn't have enough power to amplify the low and mid frequencies anymore, and it seems to us the volume knob isn't doing much, it can still drive the high frequencies to unsafe levels (unsafe for the speakers, that is). Because most of the musical content is in the middle of the range, and that range isn't increasing in volume, we don't realize that the treble has got to an unsafe level until it's too late and the tweeters let the magic smoke escape.
That's why it's always the tweeters that are killed by clipping, not the woofers.
At least that's how I understand it.
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whoaru99
Epic Member
Your point being "LOUD" generically speaking, as in unquantified in any way?
restorer-john
Addicted Member
As always in these discussions, the big contributor not mentioned, in many of these tweeter destruction events is instability or oscillation in the amplifier itself, caused by transients. Particularly amplifiers made during the DC-Daylight wars in the late 70s and into the 80s.
An amplifier oscillating above the audible bandwidth, even for a few mS can take out a pair of tweeters in the blink of an eye- leading to a "what just happened?"event.
An amplifier oscillating above the audible bandwidth, even for a few mS can take out a pair of tweeters in the blink of an eye- leading to a "what just happened?"event.
I can personally vouch for this. Yes, I'm the operator.
Okke 70s
Super Member
Ah... was that part of the oil-crisis?
I have pushed them like crazy in the teenage years, but don't think I ever blew a speaker (only an amp or two). The speakers that where basically guaranteed to blow a tweeter where those of the horrible mini-midi sets all my friends had in the 90's. It didn't matter though, "Nevermind" sounded just right in total clipping mode with one blown tweeter!
But basically I was just wondering about those DC-Daylight wars..
restorer-john
Addicted Member
It's my name for it. Manufacturers were extending the power bandwidth and overall bandwidth in competition with each other. Advances in semiconductors enabled amps to extend their -3dB points out to 600kHz or more. Some brands even specified unity gain numbers into the MHz region.
Those amplifiers were often on the edge of stability with anything other than resistive loads. Throw difficult speakers on, wind up the wick and throw a few transient events into the mix and they became high frequency oscillators with hundred of watts behind them.
Sansui, Kenwood, Pioneer, Denon all did it and as they aged, many of the caps used to keep the amps stable, aged badly.
Many of these kept (still keep) techs busy at the bench.
Gigantic
A big, big love
I was expecting a blonde joke...Whew!
From the thread title, I was worried it might get ash-canned.
Well... I have a super old one... Let's see if it survives...
____________________
Two “Leisure Suit Larry-type” traveling salesmen were on a road trip to a convention. They stop at one of those dusty old cafe/market/gas stations on the highway.
They sat at a table.
The older guy says to his young protegee, “Hey, these country girls are super easy! And it won’t cost anything. Watch!”
The waitress came by to take their order. She was this bleeding-through, dyed-blonde, middle-aged woman. Chewing gum.
“Two SPECIALS!” The older guy left a $20 bill on the table and winked.
Ten minutes later, the waitress returned with two brown paper bags, blew into them, then twisted the tops.
She winked. “Here you are boys! Two blow jobs to go!”
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I run duel Yamaha MX-1000's (260 watts 8 ohm) on a bi-amped system. Over kill on the tweeters and Midranges to be sure, however, I love the amps and I drink responsibly (as they say). I share the opinion that It's not the amp it's the owner (as pointed out above).
Garry
Garry
