ok, i am on my 2nd set of components, i had BA pro60's up front but my driver side mid blew out. I recently installed the sr6500's and when i turn up the volume the driver's side mid starts to crackle....what can i attribute this to? i am running a jl 300/2 to push the components.

edit:
also, since my driver's side midbass begins to crack when turned up to high volumes...is it damaged Irreparably? if so, i'll be moving on to my 3rd set of components but i want to nip this problem in the bud now....thanks guys.

 

I don't know the wattage ratings on your speakers but will assume that it's higher than your amplifier's output. Otherwise the solution is simple.

You're likely over driving the amplifier or your headend. A clipped input from the headend or an over driven pre-amp stage is going to send out a signal just designed to eat speakers. Back in the day when I did custom car stereo installations we replaced more 100W speakers blown with 40W POS amplifers than we did 100W speakers blown by 250W amplifiers.

I've come to the conclusion that males under the age of 30 do not have the ability to hear clipping at levels even up to 10-20%

The safest way to set your system gain up is with a 0 dB test tone and an oscilloscope. You play the test tone CD back while watching the output on the o'scope. When the nice smooth sine waves start to square off - even a little bit - that's the clipping point and the volume should never be advanced beyond that point. No matter what the volume output is that's "10". Don't go to "11"! About half the head-ends I've tested clip before reaching "11" (maximum volume **** rotation).

My Pioneer AVIC N2 clips before "11".

Once you've got that maximum capable output from the headend you then put the hearing protection on and start with the amplifier's gains. Start with them down to the minimum. Connect the o'scope to the speaker outputs now. Start the test CD, put the volume to "10" and start advancing the gains while looking at the o'scope for those clipping indications again. Some good amplifiers will have clipping detectors with LEDs that flash, those are better than nothing but I'd rather see it on my o'scope.

Finally you'll need a microphone and pre-amp to test the speakers to see if they're being over driven. When a speaker drives to its physical limit it will stretch beyond what it was designed to do. Most good speakers have a whole lot of headroom - range to be driven hard. A microphone will also help you find speaker cabinets resonating, loose and buzzing interior parts.

Normally when you smoke a speaker causing it to crackle its gone forever. Sometimes you can heat the coils up so hot that the glue breaks down and the bobbin that the coil is wound on breaks loose from the cone.

 

great write up, i appreciate it....but why is my driver's side mid the one that is suffering?? the passenger side is always in perfect condition...

 

There have been other reports of this problem (like yours). It must have something to do with the door and its internal structure. Dunno know though what it is.
--Spike