three out of four tweets blown!!!!

[SRim23]

ive got two sets of polk momo components one set rear one set front.... they are hooked up to a planet audio big bang 300.4 amp.. all of a sudden three of the four tweeters are blown and the fourth one is crackling but all four mids are fine. they are all properly hooked into the passive crossovers and the amp is set to high pass filter on. how could all the tweeters be damaged and the mids are ok and could the amp getting hot frequently caused these to blow?


background on the amp= this amp i was told my a local dealer was only produced my planet audio for a few weeks because it runs at such a high temp hence why i mentioned that it runs hot...


please help soon

[squeak9798]

It has nothing to do with the amplifier's operating temperature.

My guess would be that the gain was set incorrectly, which caused clipping.

[SRim23]

if it were the amp gains the mids wouldnt of been damaged as well. thanks for the reply any other theories?

[95stroked1500]

no, the coil in the tweet has much smaller wire than the mids. it's the easiest and first to take damage.

[Frankensuby]

Which Polk series was it? The DB or MMC series?

[squeak9798]

if it were the amp gains the mids wouldnt of been damaged as well. thanks for the reply any other theories?

As was mentioned....tweeters are far more sensitive to clipping than mids. The mids typically will survive longer than the tweeters in most situations, which obviously means the tweeters would fail first.

Sounds strikingly similar to your situation, eh?

Given the quantity of failure (all 4 tweeters at the same time), about the only other explainations would be simply too much power (regardless of gain setting) and overboosting of high frequencies via an equalizer (which, again, would have resulted in either severe clipping or simply much power).

[GordonW]

Clipping an amp will almost always take out the tweeter... and it's not ONLY because the tweeter is smaller and has a smaller coil.

In a clipping situation, what happens is that you LOSE low frequency energy (the "fundamental", or base tone of a sound), and GAIN higher frequency harmonics.

Harmonics, upon clipping, occur at MULTPLES of the original frequency... if the original frequency the amp was putting out, was, say, 1000 Hz, then the harmonics would be 2000Hz, 3000Hz, 4000Hz, 5000Hz... 10000Hz, 11000Hz, etc. So, actually, there winds up being LESS signal at the ORIGINAL lower frequency, and all of these harmonics wind up sending out power to the speakers at HIGHER frequencies... and guess what, the TWEETER gets them. The midrange and woofer have LOW PASS crossovers on them, that LIMIT how high the frequency they can get, but the tweeter goes UNLIMITED high in frequency from its crossover!

So, even if you were to plug a midrange into the crossover for the tweeter, you, in theory, could probably blow it up too, if you clipped the amp hard enough!

There's a general rule of thumb I use: Too much power blows up woofers (over excursion, plain old overload, etc). Too LITTLE power blows up tweeters (clipping!). However, clipping doesn't ALWAYS come from an amp... if the PREAMP or ELECTRONIC CROSSOVER or HEAD UNIT is clipping, the tweeters will wind up just as dead. Make sure ALL the gains are set properly, NOT JUST the amps!

Regards,
Gordon.

[SRim23]

it was the mmc series all the speakers came in the car when i bought it so i thought i was screwed cause all warranty information on polk audio site says it only is valid for the first owner. well i took them up to the shop i know the guy bought them from and they said they could warranty them for me so im waiting for polk to send the new ones.

thanks for the help i think i might of overpowered them. my amp is rated exactly what the sets are rated but alot of the planet audio amps are underrated anyway so im thinkin that maybe i overpowered them think im going to sell the 150.4 and go with planet audios 75.4 instead just to be safe

[zachzchw]

it was the mmc series all the speakers came in the car when i bought it so i thought i was screwed cause all warranty information on polk audio site says it only is valid for the first owner. well i took them up to the shop i know the guy bought them from and they said they could warranty them for me so im waiting for polk to send the new ones.

thanks for the help i think i might of overpowered them. my amp is rated exactly what the sets are rated but alot of the planet audio amps are underrated anyway so im thinkin that maybe i overpowered them think im going to sell the 150.4 and go with planet audios 75.4 instead just to be safe

Keep the better amp, set it correctly this time.