US3983337A - Broad-band acoustic speaker
- Google Patents. Nothing but cubic money now to keep us from having a true 20-20 kHz point source driver. 😉
GM
- Google Patents. Nothing but cubic money now to keep us from having a true 20-20 kHz point source driver. 😉
GM
I was 16 and didnt even know what soundstage or point source was, when that guy filed the application. I was thinking "All I know is the tweeter needs a 4uf NP cap" while this guy "Each subsection of the coil is centered on the boundary of the magnetic flux field so that as one subsection moves into the flux field, the other subsection moves out of the flux field at the same rate".
I didnt even know anyone who set their speakers 8 - 10 ft apart at one end of the room back then. I remember one guy hung his Bose 501s from the ceiling - and I thought that was just so cool.
I didnt even know anyone who set their speakers 8 - 10 ft apart at one end of the room back then. I remember one guy hung his Bose 501s from the ceiling - and I thought that was just so cool.
Seen/auditioned 901s in various layouts including suspended, but can't recall ever noticing any of the other product line except the original Acoustic Wave Music System that quite a few folks found $800 [IIRC] [~$2033 today] a fair price/performance ratio.
Anyway, the Lorelei Babb prototype that interests some of us is for lack of a better description, a true compact 'full-range' 4th order compression driven point source horn with an ultra high, spiderless 1" [1.2"?] Xmax combined with at least a 400 W peak power handling to offset its abysmal efficiency, controlled directivity out to ~140 deg [IIRC] and like all Babbs, a waterproof design for marine apps.
GM
Anyway, the Lorelei Babb prototype that interests some of us is for lack of a better description, a true compact 'full-range' 4th order compression driven point source horn with an ultra high, spiderless 1" [1.2"?] Xmax combined with at least a 400 W peak power handling to offset its abysmal efficiency, controlled directivity out to ~140 deg [IIRC] and like all Babbs, a waterproof design for marine apps.
GM
I see a frictional o-ring there. That’s going to have a hard time moving at 20kHz without a lot of heat friction. Also, a large stroke piston air pump to a horn is what this is. I am not sure the sound is going to be very hi-fi. Also, 1inch stroke at 20kHz is 504m/sec that’s above the speed of sound. About Mach 1.5. Compressible flow regime.
Has this ever been made into a good sounding driver for hifi audio?
Has this ever been made into a good sounding driver for hifi audio?
GM was able to bring a pair to the Atlanta Diy Audio show back in 2002 ?
They were good, very good. I was interested in buying a pair but was a
little turned off by the price and the low efficiency.
They were good, very good. I was interested in buying a pair but was a
little turned off by the price and the low efficiency.
Oh yes indeed: as GM noted, the Lorelei is rightly regarded as one of the finest wideband drivers ever built. Arguably 'the', with the partial exception of some of Olson's big [partial coax] units, which were functionally an inverse approach & significantly larger. Alas, the company as-was couldn't survive the financial crash and very few were made to the original / prototype spec. As a result, not many people have even heard about them.
Hmm. I'm going to have (another) chat with the guys at Markaudio -see if they can do something about bringing this back in some variation with the patent having expired. Be a shame if the Lorelei design (or the key aspects anyway) were simply lost. Pricey on the tooling, but it'd be worth it.
Give GM & myself chance 😉 -I know he's got 'a bit on' (chronic understatement of the decade) at present, & I'm currently up to my ears with work, a funeral for one of my closest friends, my mother's birthday and a dose of autumn 'flu, so time is limited. As advance though -no 'secret sauce' (ensure your alarm bells ring if anybody ever claims anything like that), just damn good engineering.
Okay, I need a break, so:
Yes, it's spiderless, but not in the same sense as most (any) other. The Lorelei had a number of features Alan worked on from the '70s, including a split coil (sort-of dual gap) motor a little like the later XBL, which allowed both a very linear B*L(x) curve, with reduced HD and FMD, at the price of fairly miserable efficiency -that's just nature of the beast for that sort of motor topology & a fairly small cone. Coil centring, rather than relying on a spider and / (or) conventional surround was done by a varied-rate surround and effectively a form of low-friction bearing-race between the former & pole-piece. The cone had some interesting features too -dissimilar materials part-direct coupled with different transmission speeds & very shallow hyperbolic (IIRC) profile, so the polar behaviour was unusually wide / consistent for a single unit.
Yes, it's spiderless, but not in the same sense as most (any) other. The Lorelei had a number of features Alan worked on from the '70s, including a split coil (sort-of dual gap) motor a little like the later XBL, which allowed both a very linear B*L(x) curve, with reduced HD and FMD, at the price of fairly miserable efficiency -that's just nature of the beast for that sort of motor topology & a fairly small cone. Coil centring, rather than relying on a spider and / (or) conventional surround was done by a varied-rate surround and effectively a form of low-friction bearing-race between the former & pole-piece. The cone had some interesting features too -dissimilar materials part-direct coupled with different transmission speeds & very shallow hyperbolic (IIRC) profile, so the polar behaviour was unusually wide / consistent for a single unit.
Ah, I remember reading about these over at the old fullrange driver forum. That dual voice coil layout is interesting.
It is indeed. 🙂 The cones were pretty special as well, although as GM said, extremely wide polars can be too much of a good thing if the room / positioning isn't optimal.
Easier to dampen HF than to create out of nothing. It's almost a luxury problem. 😉 Anyway, Markaudio "is good with cones and dispersion" so with my limited insight, I'd guess that would not be the part of the driver to replicate.
