"1) The Hill Plasmatronics Type 1 was an (almost) full range plasma loudspeaker -- Hill used helium rather than air to generate the plasma, thus eliminating (or minimizing) the ozone issue. " Yeah, but everyone talked funny who listened to them.EV also sold the duKane Ionovac as the EV T3500. The big problem with these (besides the ozone, of course) was (is) very low sensitivity, even with horn loading. I believe (??) that the horn on the Ionovacs (duKane or EV-branded) is a diffraction horn not unlike that used on the EV T35 family.
EV, bless their hearts, still has the docs for the T3500 on their website
That part of the EV website is down as I type this but here's an archive copy, if anyone's interested.
I will also mention in the context of plasma drivers/tweeters.
1) The Hill Plasmatronics Type 1 was an (almost) full range plasma loudspeaker -- Hill used helium rather than air to generate the plasma, thus eliminating (or minimizing) the ozone issue.
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2) Nelson Pass, famously, injured himself via ozone exposure/inhalation working on an extended range plasma loudspeaker.
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The speaker of my dreams is Passive, 3-way and with a minimum woofer of 15 inches.
It was actually already built and it's called JBL Everest DD67000
A CBT shaded, curved array with 4" coaxials with KEF design (minimises disadvantages of configuration) and HF performance, but Purifi 4"-level performance in LF/MF. Minimal lobing, wide but controlled directivity in both horizontal and vertical directions, no floor bounce and reduced ceiling bounce. DSP linearisation of phase and FR to +/-0.5dB target curve in the listening window and linear phase (down to 20Hz if possible, given the extreme extension and linearity afforded). Crossed to a single-bass array with state-of-the-art large sub drivers (eg. Adire Audio).
For narrower directivity, a lower-diffraction Synergy horn, adapting JBL M2/Geddes OS/SEOS techniques for multiple-entry, using a coincident beryllium compression driver and SOTA mids (maybe Purifi 4"), Purifi 6.5" and SOTA woofers (think JBL 2216ND). Single bass array subs. Again DSP linearised in both time and frequency domain, plus crosstalk cancellation with individualised HRTF (think BACCH). State-of-the-art room treatment (think Blackbird Studio C).
THX power amps and maybe the Okto DAC8 as preamp + digital XO on a silent PC/music server.
Either way, max SPL >120dB across the entire band. Distortion at Revel M106 tweeter levels (-70dB at 96dB/1m), except throughout almost the entire band bar low bass.
Sounds like what you're wanting is more likely be achieved with a headphone than a speaker.My dream achievable speaker would:
1. Increase direct/reflected sound power (near field speaker).
2. Employ sealed cabinet design that minimizes both diffraction and resonance.
3. Be an actual point source (single driver) with deviation from target curve of +/- 1.5 dB from 40 Hz to 18-20 kHz.
4. Be able to provide an average 85 dB A- weighted SPL.
Non achievable:
1. Completely eliminate room contribution at the listening position.
2. Be able to extract only the front wave out of the driver membrane and present it at the listening position without contributions from the back wave.
3. No diffraction and no resonance added to front wave.
4. Be a point source with less than -60 dB distortion throughout the entire audio range.
5. 0.5 dB or less measured deviation from target curve
Sounds like what you're wanting is more likely be achieved with a headphone than a speaker.
I was really just joking. I really don't like headphone listening myself and do it as little as possible.Not the same acoustical load {headphones vs. speaker} to the eardrum. They just don't sound the same. Also, the HRTF of a source that is straight to the side and very close to the head is very different than that of a farther and at standard stereo triangle configuration angle one.
I have only heard the Parts Express Epique speakers at Cedia. They were impressive. I believe Rick Craig has built some CBTs with better drivers. I would like to hear a pair.
These were a project with Rick Craig and Kevin Kendrick. Really great looking and good sounding speakers.
Absolutely no disrespect, but what's the logic behind 20 dome tweeters in a vertical line?
(p.s. - love your site!)
These were a project with Rick Craig and Kevin Kendrick. Really great looking and good sounding speakers.