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Has anyone ever heard of installing a Bozak mid range and a pair of Bozak tweeters Into a KLH ONE ( the klh one is a cabnet with two 12" acoustic suspension woofers with a mechanical rolloff of freq.around 1200 htz.) The cabnet was made to accept a Janszen electrostatic speaker which I no longer have, so I thought that would be a good place to install a Bozak mid & 2 tweeters,or two mids and mount the bozak array of tweeters on top of the cabnet. The KLH is 16 ohms but I understand it has about the same efficiency as the Bozak speakers.If Pat Tobin is out there, maybe You could give some of your expertise on this esp. concerning the cross over configuration etc.Thank You all in advance for your input. Bob audiotube
Follow Ups:
a pair of small Magnepans? The new CC3, which was designed to be a center channel speaker, has a similar configuration to the vacated Janszens and certainly will handle the frequency range. Nice speakers on their own, too.
Thanks for the tip on the magnepans. It seams the electrostats and planars just don't have the tonal quality that I like,although their great speakers and very clean. However, I'd still like to audition them. If anyone knows where I can hear them in the Atlanta area please give a holler.
Well, I thought that they might be a closer replacement of the Janszens than anything else in terms of sound and form-factor.
Hi Bob - I know a little about Bozak, but nothing about KLH. So I can't even begin to guess about the relative efficiencies. Except for one observation - "in the early days" Bozak was considered a system of low reference efficiency when compared with other large systems - Altec, JBL and others, especially Klipsh. But when the acoustic suspension systems came out with very low reference efficiency, suddenly the Bozaks were at least medium efficiency, and I haven't heard anyone call them low efficiency since! So it's possible that the Bozak mid and tweeter pair might even be higher reference efficiency than the KLH woofers. If that is the case, you could lose an easy 6 dB by using the 16 ohm version of the Bozak midrange. But if the 8 ohm version is closer in efficiency, there is nothing wrong with using a mix of 16 and 8 ohm drivers, so long as the xover is optimized for the individual driver.I think that likely no better midrange has ever been made than the Bozak B-209B/C, so it's a worthy project. But there is the danger that the superb transient response of the midrange might contrast audibly if the KLH woofers aren't as good in that respect; it is discomforting to hear a clear difference in any parameter of audio response from one frequency range to another. The Bozak woofs are damned good in transient response. If you use the recommended first order xovers, you would want to cross over at about 400; stay at least an octave away from where the KLH woofers roll off naturally.
There are two ways to go with the tweets. I don't suggest the 4-pair array; that was great for the mono concert grands, but the very wide dispersion, great for a single mono system at the center of a wall, is not as effective for stereo. Furthermore, that array was brought out to handle (with 8 individual tweeter units) the 100 watts that the Concert Grands could eat, using the early B-200X tweeters. With their paper cones, they couldn't handle the power of the later B-200Y and B-200Z, whose aluminum cones offer the world's best heat sink for the VC.
Depending on the power the KLH woofs will handle, I would suggest either a single tweeter pair, or an array of four (two pairs). Yes, I know the Bozak Symphonies and stereo Concert Grands used a row of 8. That's convenient for impedance matching, but not otherwise necessary except in a 100 watt four-woofer system such as the CGs; certainly not necessary for power handling in the Symphonies. If you are going to run more power than 30 watts, I suggest an array of four. I can make suggestions for impedence matching off line; this is getting too long already.
For tweeters, definitely not the paper-coned B-200X, the ones with the bright center caps. By far the best are the B-200Z, but they were introduced only in 1977 and are relatively scarce. But they are flat to 20kHz and cleaner than the law allows.
Far more plentiful is the B-200Y, made for about 15 years. There's good news and bad news about the Y. The bad news is that, like the B-200X, the Y's roll off softly in the top octave. The good news is that the Y's are 9 dB hotter than the Bozak B-199A woofer and B-209B/C midrange, so unless you want to run them that hot, there is level to play with. I use a T pad to drop the excess 9 dB, bypassed by a 2.0 uF cap to tilt the highs back up above 10 kHz. Works like a charm; with that setup it's hard to hear the difference between them and the Z's.
Bob, while an exhaustive treatment would be far too lengthy for this forum, and I don't know anything about the KLH woofs anyhow, I hope this will give you some starting pointers. Feel free to rattle my cage for further discussion.
With best holiday wishes,
Pat, Thanks for your quick answer to My post. Concerning the efficency question, Janszen electrostatic speakers were rcomended for two Bozak woofs or the KLH woofs, so therefor I assumed the efficency would be about the same. The KLH one woofs are excellent speakers, go down to about 27 htz and are tight,fast and well controlled. They were excellent with the electrostatics (fast) and were almost seamless. the only reason I sold the Janszens was because of the High humidity on Long Island where I lived at the time.(only bedroom A/C at the time)The Janszens never sounded good during high humidity, but when it dried out for a few days they were very good. However I always missed the great tonal quality of the BOZAKS that I almost bought but didn't because of size (room & speaker). I'll contact you when I'm ready to go ahead with this project so you can give me some advise onthe crossover config.,if thats ok with you. Have a great hoiday season! Bob
Bob, All Bozak systems prior to the very late '70s were the same efficiency, whether single, two or four woofer. When two woofers were used, they were in series, with a single 16 ohm midrange and tweeter pairs in series, driven from 16 ohms (B-305 systems) or, in the case of the Symphonies, two 16 ohm woofers in parallel and everything else was 8 ohms, driven from 8 ohms. So it all came out in the wash to the same SPL/watt.I look forward to hearing more from you on this interesting project.
Happy New Year to all,
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