Speakers for leading edge, transients, speed and big sound

For some ionic tweeters, like the Hill Plasmatronic, a chemically inert gas was injected around the electrode to prevent it from corroding in the highly reactive environment of an ionized plasma.  Even with such gas protecting the electrode, it would get eaten up by that harsh environment.

@devinplombier:

Example of a short excursion woofer that @larryi is referencing see here.

The JBL 2220 is a 15'' woofer with a short excursion and has a frequency range of 40 Hz-2 KHz while the JBL 2235 is a 15'' woofer with a long excursion and has a frequency range of 20 Hz-2 KHz. The 2235 woofer will reach two octaves lower in the bass than the 2220 woofer see here. 

Almost all HiFi woofers suffer from this problem (woofer dynamic offset) see below:

''Woofer dynamic offset is a problem long known about but seldom discussed or treated. With high input power at low frequencies, many woofers tend to shift their mean displacement forward or backward until the coil is nearly out of the gap. This is most likely to happen just above each low frequency impedance peak of a system. The result is a high level of second harmonic distortion and subjectively a bass character that loses its tightness at high acoustical output levels [4]. The cure for offset, as shown by T, H. Wiik [6], is a restoring spring force that increases in stiffness at high displacement in an amount that counterbalances the reduced B field at the extremes of voice coil travel. Such a nonlinear spider will in fact reduce distortion and eliminate the tendency to offset.'' See full article here.

Mike

@simonmoon Thanks, I very much appreciate your retort.

"They use a pulsating plasma flame to excite the air itself. No need for an external gas supply.

They're lifespan is extremely long, since there are no moving parts. 

Another company that uses ION tweeters, which I like even better than Acapelle, is Lansche audio. I heard their speakers at T.H.E. SHow last year. 

Their ION tweeter, if it needs to be replaced, is less expensive than other high end speaker's tweeters."

 

@ditusa Bill Woodman who founded ATC in 1974 solved this problem by using "underslung" edge wound voice coils in a longer and tighter gap which eliminated the "offset" issue while reducing distortion up to 20dB throughout the driver's frequency range. In addition, this reduces the usual swings in impedance as well as radical changes in phase angels resulting in flat impedance response without resonances. The caveat being the need for enormous magnet structures along with considerable reduction in efficiency. Essentially though, you could use any type of amplifier typology to drive their speakers without harm to the amplifier but to get the speaker system to come alive you need minimally a hundred watts high current solid-state power.

"Example of a short excursion woofer that @larryi is referencing see here.

The JBL 2220 is a 15'' woofer with a short excursion and has a frequency range of 40 Hz-2 KHz while the JBL 2235 is a 15'' woofer with a long excursion and has a frequency range of 20 Hz-2 KHz. The 2235 woofer will reach two octaves lower in the bass than the 2220 woofer see here. 

Almost all HiFi woofers suffer from this problem (woofer dynamic offset) see below:

''Woofer dynamic offset is a problem long known about but seldom discussed or treated. With high input power at low frequencies, many woofers tend to shift their mean displacement forward or backward until the coil is nearly out of the gap. This is most likely to happen just above each low frequency impedance peak of a system. The result is a high level of second harmonic distortion and subjectively a bass character that loses its tightness at high acoustical output levels [4]. The cure for offset, as shown by T, H. Wiik [6], is a restoring spring force that increases in stiffness at high displacement in an amount that counterbalances the reduced B field at the extremes of voice coil travel. Such a nonlinear spider will in fact reduce distortion and eliminate the tendency to offset.'' See full article here."

 

Reading about the Meyer Sound Bluehorn in the MIX magazine article  (installation at the Fox soundstage for film soundtrack mixing) made me think of the original early efforts to bring sound to film using large horns, eventually augmented by woofers since the "snail" shaped horns did not deliver much bass. The Bluehorn seems to be a modern answer to large scale reproduction, taking advantage of current technology--active speakers with dedicated amps, using DSP to correct time and phase differences, etc. If you consider how well regarded some of the antiquarian theater reproduction systems are today (WE, Klangfilm, JBL), these may be their more modern incarnation. 

I did achieve a piece of this by combining the Avantgarde Duo with 15" subwoofers that use a relatively inexpensive outboard DSP system to flatten the response and got everything to gel the old fashioned way, through tuning by ear. But it's an unpredictable way to set up a system and it is obviously "tuned" to my preference in the room- not for perfectly flat response. And of course, much relies on the upstream equipment, all entirely tube based, utilizing expensive, hard to find old stock tubes. 

I'm not suggesting one go this route. (I gather the Avantgarde Trio has the option of utilizing their built-in electronics and crossovers to accomplish room integration at a price). 

There is something magical about the sound of a good horn system with SETs, though....