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Too good to be true with basically no inductance or capacitance in the audible frequency range? Hard to say. Makes one wonder what the folks at PSA have to say based on recent updates to the IRS V addressing low frequency Emit break-up mode. This video got me to wondering if all said is true could these new planar magnetic drivers be a part of the new PSA FRS series speaker? Time will tell, and hopefully here is some truth to all that was presented.
Also, an interesting connected, moving the bass towers to the rear of the room and connecting them out of phase. Room dependent to be sure.
You had to be with me in the room that day. He showed me the original EMIT driver versus what he built which drops like a rock below 60Hz but extends beyond 20kHz.
Here are his measurements. Corydon along with his Son Bob & myself will be at RMAF in October with his finished prototypes.
With a REL Subwoofer to augment the Bass (he’ll be using two at RMAF).
Should be interesting, can you share additional details regarding availability and pricing?
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Hi weedeewop,
You can email Corydon Johnson (cmj480@gmail.com) for pricing and lead times.
All the Best,
Joe Goswami
Hey Joe!
Any idea if Bob picked up the project for the EMIMs?
Cheers! Juan
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The family is looking for someone/Company who might be interested because they won’t be able to it this time. They have all of Cory’s tooling, material, and notes.
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I found parts of this fascinating, like the use of parylene conformal coating as the diaphragm material. It looks like it’s glass transition temperature is high enough (though lower than the teonex we use by about 40 C) and he’s getting good results.
Also, the way that he’s doing multiple thickness of aluminum through multiple masks of caustic etching is cool. There’s an application where I’d like to do this (for a different reason.
However, it’s clear that he has some large gaps in his speaker design knowledge. For instance, the design above shows a 6 dB baffle step loss at 3-400 Hz and this needs to be corrected or the speaker will sound very thin and forward.
Also, I wouldn’t say that speaker that is 24+ dB dB down at 20 kHz “extends to 20 kHz”.
Additional, stacking a pair vertically like that and running them full range as he does (without a crossover) will further limit the HF dispersion and make it a “head in the vice” situation where you lose all highs standing up. The line either needs to be ~4ft tall and minimizing the gaps between the driver apertures to minimize combing or there needs to be some frequency tapering between the drivers, like making it a 1.5 way, with the second driver operating below 400 Hz.
Also, the system at 250 Hz and below will be VERY displacement limited and there will be no impact without more diaphragm area (more drivers) or a hybrid system or something.
Still extremely cool and thanks for sharing.
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The problem is now that Corydon has passed. There’s really no way of reproducing or improving what he did.
Paul’s IRS V’s EMIT’s & EMIM’s were rebuilt using Paralene and I think he told me some of the magnets were oxidized severely and had to be replaced (check with Paul…he probably knows better).
One thing Corydon did tell me and you’ve hit on it as well. To make a “full range” Planar would literally be 8 ft. tall or higher and probably wider as well. I think the 20kHz remark may have been an error. The Video was a 2nd take because Stupid me forgot the plug the mic in 
It’s a design that was still WIP. I can get you in touch with the Family if you are interested in what he did (notes & so forth).
Thx for Watching Chris,
Joe Goswami
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I’m sorry, I didn’t know that he had passed. Quite a heroic amount of effort on his part. What a cool project do do in retirement!
Our mids are pretty different in that they are about 10 dB more sensitive and have higher power handling but don’t play as low. They are tensioned around 150 Hz and have acoustically resistive screens that damp the output around resonance quite a bit.
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