D-MAN Posted November 28, 2005 Share Posted November 28, 2005 Here is the 1974 Heil patent drawings. I remember these being real big back in the 70's, right along with Khorns... I guess they went extinct. DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 #2 Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 #3 Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 Interesting folded columnar bass bin... DM Quote Link to comment Share on other sites More sharing options...
boom3 Posted November 28, 2005 Share Posted November 28, 2005 Thanks for posting these, however...These aren't Heil patents, they are related to the Walsh (Ohm) reproducers. The Heil was the Air Motion Transformer (AMT) which was pretty good, although sheer economics finally doomed it. Compared to other transducers, it was just too expensive to build in a commercially viable manner. Ohm is still making a variation of the Walsh driver, although it has gotten very little critical attention lately. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 Indeed! I was confused - it was along time ago! Maybe I was thinking ESS Heil AMT-100 or something... The Walsh driver, yes, that sounds like it. Ohm- that rings a bell! How lame of me! DM Quote Link to comment Share on other sites More sharing options...
Coytee Posted November 28, 2005 Share Posted November 28, 2005 Brings back memories. I think it was the "F" model? I saw them & thought they looked VERY cool & came close to buying a pair just because of that. (this is where the memories come back) I also had some bookshelf sized speakers that sounded very nice as I recall, that had the Heil AMT tweeter. I think I used those Heil speakers in my car... [:$] Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 I think you're right - it was the "F". DM Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 28, 2005 Share Posted November 28, 2005 Yes, that does bring back memories of the Ohm F (walsh) drivers. As I remember, there was a big to-do over the sound field. Supposedly, the sweetspot was just about the entire room. They sounded pretty good when they were loud. At this time the Carver-designed Phase Linear amps were quite popular. That was the combination that I remember Ahh memories, -Tom Quote Link to comment Share on other sites More sharing options...
tofu Posted November 28, 2005 Share Posted November 28, 2005 i own a pair of ohm walsh speakers.. not sure which model Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 28, 2005 Author Share Posted November 28, 2005 Tom, you're right, they needed alot of power to get them off the ground and Phase Linear was there at the right time. The unique thing about the Walsh "F" is that the sound is in-phase with 360 deg. coverage, not to be confused with planars which are 180 out of phase and have at best 180 deg. coverage. Bose is still infatuated with the technique... they introduced a 180 degree semi-omni speaker for PA use. Don't ask me why. However, a friend of mine reports that it fills the rather large hall of their church very evenly, to my great dismay. Granted, it's crap, it has to be; it's Bose. Here is a pic of the dreaded Bose object of which I am speaking. DM Quote Link to comment Share on other sites More sharing options...
78Khorn Posted November 28, 2005 Share Posted November 28, 2005 Back in 1978 I traded in my ESS monitors (6 ohm speakers) for my K-horns. The ESS had a Heil Air-motion Transformer for the high and midrange sound and a 12" bass with a passive radiator for the low end. The highs that the HAT put out were excellent but the lower midrange and bass were a little week. The speakers were capable of biamplification but I never got that far. The dealer I dealt with had a policy that you could trade in your speakers in the first year you owned them and receive full value against a set of speakers costing at least twice as much. Bye bye ESS, hello K-horns. 78 Khorn Quote Link to comment Share on other sites More sharing options...
boom3 Posted November 29, 2005 Share Posted November 29, 2005 Heil also made a full-range AMT briefly. The regular AMT, when scaled up, had severe cavity resonances. The bass AMT was this weird contraption of clear plastic disks driven by carbon fibre rods. The reviews were not enthusiastic. A long-ago ish of Speaker Builder featured a homemade AMT coupled to a horn. An interesting and commendable project. Paul told me once that the AMT was a good transducer if operated in a unipolar manner (with the back enclosed) but he still felt traditional horn drivers were the way to go. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted November 29, 2005 Share Posted November 29, 2005 Back in 1978 I traded in my ESS monitors (6 ohm speakers) for my K-horns. The ESS had a Heil Air-motion Transformer for the high and midrange sound and a 12" bass with a passive radiator for the low end. The highs that the HAT put out were excellent but the lower midrange and bass were a little week. The speakers were capable of biamplification but I never got that far. The dealer I dealt with had a policy that you could trade in your speakers in the first year you owned them and receive full value against a set of speakers costing at least twice as much. Bye bye ESS, hello K-horns. 78 Khorn In 1978 I had a roomate with a pair of these and thought they sounded great. When he moved out I ended up with a pair of (Heritage clones) by North American Sound and never looked back. Quote Link to comment Share on other sites More sharing options...
Guest BobG Posted December 1, 2005 Share Posted December 1, 2005 In 1971 or so, I had large Advents and was hot to get something better. My local dealer showed me Quad electrostats and KLH Nines (also estats but huge) but neither would work in my college room. The only workable option was B**e 901s so I ordered a pair. Fortunately, before they came in, my dealer got his first two pair of the ESS Heil AMT-1 speakers. These were the first AMTs on the US market. 10" woofer and big AMT. They were much better than the 901s in my opinion so I bought his "extra" pair which turned out to be intended as demos for their other store. I never looked back and never owned any B**e. A friend in Switzerland builds speakers commercially using a newer version of the AMT. The driver has its charms. Quote Link to comment Share on other sites More sharing options...
JBryan Posted December 1, 2005 Share Posted December 1, 2005 "Bose is still infatuated with the technique... they introduced a 180 degree semi-omni speaker for PA use. Don't ask me why. However, a friend of mine reports that it fills the rather large hall of their church very evenly, to my great dismay. Granted, it's crap, it has to be; it's Bose." I heard these in a PA application a few months ago. Mike Keneally was demonstrating Taylor guitars and he had 2 of these and a small processor/amp instead of the usual PA setup. They sounded clear and clean but his bass player needed a sub to play his acoustic bass through. Have fun, Bryan Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted December 1, 2005 Share Posted December 1, 2005 Speakers using the Walsh driver are still in production, still made by Ohm. The logo is still the same, but I'm guessing the company has probably changed hands a couple times since back in the Tech HiFi days of the Ohm F. http://www.ohmspeakers.com/styles_walsh.cfm Quote Link to comment Share on other sites More sharing options...
lost_at_c Posted December 3, 2005 Share Posted December 3, 2005 I, too, remember the Ohm F. In '74 or so I took a pair home to demo. Through the mist of time, they had a wonderful, even soundstage. Nice frequency balance, too. Sounded good from everywhere in the room. And $600 a pair. They also red-lined the living daylights out of the Marantz 32 I was running at the time. 60 wpc was not nearly enough. But I was young and stupid and instead of upgrading my amplification, I stayed with my Rectilinear mini-IIIs. Things worked out though. Shortly thereafter I encountered my Klipschorns and never really looked back. Jim Quote Link to comment Share on other sites More sharing options...
Marvel Posted December 3, 2005 Share Posted December 3, 2005 I think you should try this ion tweeter on one of your systems. No moving parts, other than the arc, and that isn't really a 'part'. ACAPELLA ION TW 1S (Ionic Tweeter) The Acapella ion tweeter Ion TW 1 S is a perfected and sophisticated loudspeaker chassis, whose exceptional performance and qualities can only be enjoyed completely if used properly. It was designed to reproduce the harmonics of the music as detailed as possible. To reach this goal, a design with the smallest possible mass had to be developed. Relative to its function the Acapella ion tweeter has no mass! To carry out this project, a very unusual kind of design had to be created. High voltage within the unit produces a constant arc. This arc is modulated with the musical signal (flame oscillates with the time of the music). This is the reason why the number of electrons within the arc varies. A larger or smaller amount of electrons requires similar space. Due to this variable need of space the surrounding air molecules have to dodge the more or less quickly. This evasive action or bumping of the air molecules generates over-, resp. underpressure and, therefore, sound. In this way, the Acapella ion tweeter is able to reproduce sound without membrane and without mass Regarding transient capabilities and phase stiffness, the obtained sound quality cannot be realised by using conventional tweeters. Comparing the ion tweeter with other tweeter systems, its unobstrusive sound image will attract you. This kind of reproduction is to be attributed to the lack of harmonic and transient distortions. Technical data Sensitivity (aktive Tweeter): 1,5Volt / 0 dB Impedance: 600 Ohm Sound pressure level: max. 110 dB - 1 m / 1ms Slope Input filter: approx. 12dB/octave Frequency response: 5kHz - >50kHz (variable crossover frequencies ) Mains voltage: 234 Volt / 50 Hz Standard Optional 110 -, 117 -, 227 Volt / 50 - 60 Hz Dimensions H x W x D: 150 x 300 x 260 mm Weight: 15 kg Quote Link to comment Share on other sites More sharing options...
Marvel Posted December 3, 2005 Share Posted December 3, 2005 Actually, since you were talking about Heil, here is a shot of the Who at Madison Square Garden in June of '74, with Bob Heil speakers on the left side (white horns): Quote Link to comment Share on other sites More sharing options...
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