Gilmore Audio planars revealed

i mentioned 18" jumpers between woofers but that would be based upon a series configuration which may well not be the case. perhaps sellerwith or gilmore himself will say how they are wired.

it's four days later and no response to questions and comments. it makes you wonder why, and how they're going to react when people ask the same things.

I really don't blame Sellerwith... for taking a break. I am beginning to feel sorry for him, like the poor bank loan officer in the Ditech TV ads.

if you want to feel sorry for sellerwith that's your choice but i don't, considering his self-assertiveness, his demeaning characterization of those who express doubts as "silly", and his lack of factual response to all technical questions and challenges. in my experience a customer is treated with kid gloves as a guest and is respected, and the seller is the one who has to earn respect. nobody "owes" the seller anything. quite to the contrary.

I've been out of town and/or very busy the past couple of weeks, so just now got back to this thread.

Sellerwithintegrity, I apologize for mistakenly typing "3 mil" as the thickness of the kapton diaphragms; of course it should have been ".3 mil".

Lugnut, just for the record, "Duke" and "Sellerwithintegrity" are different people - "Duke" posts under the Audiogon moniker "AudioKinesis", and over at the Asylum under "Duke". So please don't give me credit for "taking the heat" here - I wasn't even in the kitchen!

The reason for using a weak magnet/low Qts woofer in a dipole was well laid-out by Bob Carver years ago, and goes something like this: Dipole cancellation results in a 6 dB per octave rolloff in the bass region. This is in addition to the inherent shape of the woofer's response around resonance, as predicted by its Qts. If we use a woofer with a carefully chosen very high Qts (weak magnet) and appropriate resonant frequency, taking the baffle size and shape into account, then the natural response "hump" of the high-Qts woofer can compensate for that 6 dB per octave rolloff. The baffle shape and woofer parameters can be optimized together to approximate an ideal target response.

I would expect that at very low frequencies the output of the Gilmores is displacement-limited long before the approximately 2000 to 4000 watt peak thermal limit is reached, as predicted by the spreadsheet on Siegfried Linkwitz's site (mutual coupling between drivers and large vertical path length will give greater bass output than predicted by the driver area and baffle width alone, but by how much I cannot say). Most loudspeakers will displacement-limit at low frequencies well before their thermal limit is reached. For example, I've played around with JBL woofers that have a thermal power handling limit of 600 watts RMS, but are displacement-limited to less than 1/10th of that figure below 25 Hz in a vented enclosure. Nevertheless, JBL is in compliance with AES power rating conventions to claim a power handling capacity of 600 watts RMS (which would imply far greater power handling on peaks, though they don't specify the peak power figure).

The example given above of the "wave" in the football stadium is actually a transverse (or shear) wave, with particle motion perpendicular to the direction of wave propagation. Sound waves are pressure waves, and most importantly are set in motion by physical displacement of the air particles. The mass of the air displaced by the diaphragm movement can be calculated and compared to the mass of the diaphragm itself.

While I wasn't the one sitting in the hot seat this time around, I hope to be there one day. I've dreamed of bringing out my own loudspeaker for some time now, and will probably be disgustingly enthusiastic about it when that day finally comes. In the meantime, I'm looking forward to getting to know the Gilmores first-hand.

Best wishes,

Duke