My friend and I listened to music with a few beers in us.

The next thing we know, we cranked the volume from loud to very, very loud. (maybe 110 dB at the listening position)

Believe it or not, we were listening to choir music with some serious dynamic range.

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Track: Adolphe Adam’s O Helga Natt (O Holy Night)

Artist: Alf Linder, Marianne Mellnas, Oscar's Motet Choir, Torsten Nilsson

Album: CANTATE DOMINO

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The little 12cm Scan Speak midrange (12mu8731), was playing from 300 Hz to 3.8 kHz and was taking in way more wattage than it was designed to, while being driven by the big Class A, Krell 300CX.

With no option to move the surrounding air, the heat built up inside the 12MU8731 voice coil, giving it no chance of cooling.

I think that it moved less than 1mm total. (eye balling) so the voice coil air flow was nonexistent.

 

Then… the inevitable happened. The voice coil cooked and filled the room with that familiar lovely burning smell.

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Afterwards, I replayed the "guilty track" and had my Fluke 87iii true RMS multi-meter on recording mode to measure the peak RMS power the Scan Speak had to endure.

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Turns out I was pumping peaks of ~ 350 watts RMS!!! (yes, the Krell can push that with no distortion, which I had previously bench confirmed)

So much for an 80 watt rated driver... They failed at an average of ~2x the rated power, and included some nasty peaks of 4x the rated power.

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I have the surviving right channel left for sale :)

Center channel project anyone?

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As good sounding as the illuminators are, I'm not planning on buying a replacement unit and resume the playback.

As a result of this failure, I've reconnected my previous, trusty  98 dB/w, 2" voice coil, 6.5" cone Pro mid-range. 

They lose a tad of resolution, but the dynamics are better, and unlike the illuminators, they never run out of SPL capacity.

The amplifier runs a lot cooler as well, as I do not have to push 300 watt output.

 

So, if you want 100+ dB at 2 meters, the 12mu8731 won't cut it, unless MTM configuration, but still, you're at the limit and risk cooking a voice coil.

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I’m currently looking to get a Jean Michel LeCleach' horn as a mid-range for replacement.

I bought a very good quality compression driver set as well. (Radian 760NEOPB)

Not sure if this will pass my subjective assessment, but I know they’ll never run out of SPL capacity with those horns.

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Time will tell.

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The blown eminence PRO5w8 had a cone deformation on delivery. (factory defect)

I reported it to the distributor and got a free replacement at my door within three days! Eminence are really proud of their products and offers a real warranty.

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I actually had to destroy the "faulty unit" before they would send me a replacement.

Here’s the picture of the destroyed one.

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The pair of 5W8 will be for another project. (turns out that for HiFi, they aren't very good)