Welcome! Need support, you got it. Or share your ideas and experiences.
Return to Planar Speaker Asylum
32.212.90.185
In Reply to: RE: Price for Sawafuji Drivers? posted by hahax@verizon.net on March 28, 2019 at 11:58:38
Here are some used ones -- not sure if they're still made.
Follow Ups:
Thanks, that helps. They are worth more than I thought. And I know they haven't been made for years.By the way the ad doesn't know a thing about them. They are mid ranges and go quite low and not high. They are not tweeters. The resonant frequency is even listed as 30 Hz and I can't believe they will go to 20kHz(the 1st prototype Pipedreams speakers used them as mids up to about 6 kHz). And they really aren't planars. They have multiple voice coils per driver that are elongated ovals.
Edits: 03/28/19 03/28/19
Yeah, I was reading about them. I'd never heard of them when they were out. As I recall, Infinity made similar drivers -- planar transducers with elongated voice coils.
Infinity made planars, voice coil glued on the diaphragm. The Sawafuji actually has multiple voice coil formers behind the diaphragm. Think of taking a voice coil, cutting it and straightening it out. The advantage is a narrow magnetic gap since you don't need the gap to be big to let the driver go back and forth as in a planar.
The originally infinity drivers were planars (EMIT, EMIM, etc.), but later on, they made drivers that work this way -- oval voice coil formers behind planar diaphgrams.
Kind of off-topic, but as long as we have mentioned non-standard planar drivers -look at the Bozhen tweeters - they look like ribbons but have a thin, flat "voice coil" - I have 2 pair I've used in some small 2-ways, they are great sounding drivers. Not QUITE the "air" of a ribbon, but very close, and they work quite a bit lower ( ~1.5 kHz) with lower distortion than any similarly-sized actual ribbon tweeters.
https://www.audioxpress.com/article/test-bench-bozhen-new-audio-lab-cq66-ribbon-tweeter
The graph shows THD and FR of a CQ6. The ordinate scale isn't properly calibrated- the actual peak SPL is 100 dB at 1 meter, not 117 dB.
Interesting! I'm looking at the diagram, and wondering what it's advantage is over a ribbon or quasi ribbon design.
it's motion is more linear. Since it's a variation on a regular voice coil the gap can be small unlike a planar where the gap has to be big enough for the diaphragm to move. Large gap reduces magnetic strength massively. Also the diaphragm probably has more linear travel since at 1st the diaphragm isn't instantly resisting motion like a planar(a ribbon is different) and greater excursion reducing the area needed to reach higher loudness. Because of the creases in the driver it should have different break up characteristics than a planar.
There are a few prototypes of the Pipe Dreams line source speaker using these drivers with Pioneer horn loaded ribbon(not planar) tweeters. But Sawafuji went out of business and the Pioneer tooling broke. Or else the Pipe Dreams would have used these drivers.
Interesting, I had no idea that Pipe Dreams had done that.
You could crease a conventional planar diaphgram to increase stiffness and reduce resonances, and IIRC someone has done that -- I forget who. I imagine it would lead to some issues at the top and bottom of the diaphragm, though.
It is a unique design. Kind of a complex thing, I wonder if these are hard to make.
I think the diaphragm acts more pistonically than other planar or ribbon tweeters- that flat diaphragm's motion seems likely to be more like a piston than a rippling ribbon. I think this is the reason for the lower distortion over similarly sized ribbon or planar type drivers.
I think there is also some advantage in damping, these drivers have various mechanical features that limit degrees of freedom.
By the same token, I think we have a slightly higher moving mass than a true ribbon or aluminum-on-kapton planar, so it's performance in the top octave - while very good - does not sound quite as "open" as a "true ribbon."
The upper treble is better than domes ( IMHO ) but not quite as "open" as a real ribbon. However, the performance in the 1~4 kHz range is so wonderfully detailed and "fast" that the sound of a 2-way using one of these is kind of remarkable. Ribbons generally don't work crossed over below 2 kHz, they distort at the bottom of their ranges, I've found that ribbons work best above 3~4 kHz. Except, of course, for the really big ribbon in the MG 3.6 etc, that driver is so large that you can get good low distortion performance down to 1,200~1,500 Hz. With those little silicone dots anchoring the diaphragm along it's length, the Magneplanar ribbon tweeter acts kind of like a big vertical line array of ribbons. Not exactly like a line array of individual ribbons, but KIND OF like that. Anyway, the Magnepan ribbon tweeter is very good over it's entire range. Wonderful tweeter. Maybe the **BEST** tweeter. I've wondered if Magnepan could make a midrange driver using the same design- a wider ribbon? Might be too fragile, though.
Have we veered far enough off topic yet? :-)
Just for history Pipe Dreams speakers wanted to use the Maggie ribbon on the top end from about 6kHz on up. The designers considered it the best tweeter they knew of. But, of course and understandably, Magnaplaner wasn't interested in OEMing the ribbon.
That is interesting.
LOL, all really interesting stuff, though.
I was wondering the same thing that you were about whether they were hard to make. It looks like a lot of precision is involved, and some fairly complex manufacturing steps.
Aluminum ribbons have resonance problems -- someone told me recently that Jim Winey had complained to him in the early days that the resonances in the ribbon tweeters were worse than the resonances in the planar drivers -- but they have several big advantages, which is that since they're under negligible tension their fundamental resonance is so low. The also have excellent air damping since their mass is so low, and of course a more linear field.
OTOH, they are fragile. I asked Mark Winey once about a midrange ribbon and he said that the challenge is metal fatigue. Apparently, one of the reasons that Apogee failed was that they had too many returns on their aluminum-on-kapton (or was it aluminum-on-mylar?) ribbons.
I was wondering the same thing you were about Magnepan adapting this technology, but I was thinking of bass drivers. They can make a great midrange now -- the new midrange driver in the 30.7 is mind bogglingly good, it has an ESL 57-like purity -- but they still require huge bass panels. You can only do so much about dipole cancellation in a small baffle, so that leaves the driver's excursion as the limiting factor. Neo magnets would let you increase it, but they're expensive. So I wonder an approach like this one or the late infinity drivers (the oval voice coils).
Bozhen has some new type woofers too, but I have neither seen nor heard them
http://www.bzspeakers.com/woofer_en.html
Those look interesting. I gather that they're woofer cones in a v-configuration with a common voice coil, but beyond that it was kind of hard to make out the details . . .
there are multiple voice coils. The former is linear running almost the full length of the driver.
Interesting, thanks.
Yeah it's hard to visualize the physical form of their woofer, but they do make some finished speakers, the woofer is seen as a rectangular plate with a square opening covered by a grille of some sort, behind which is apparently the woofer diaphragm; seems the woofer diaphragm is a flat or corrugated plate, rather than a cone.
They make some pretty impressive claims for this driver's performance.
http://www.bzspeakers.com/images/bz7645/bz7645-1-large.jpg
Hard to know what to make of that! No way to sense the scale of what's behind -- corrugations are definitely a possibility . . .
The advantage is lower distortion just as you have with a BG Neo driver when loaded in its cup to create an air spring behind it. The voice coil with spider in a tight magnetic gap has fewer membrane effects and more damping. The downside is that the overall structure may turn out heavier than a plain planar or ribbon. You can see ribbon driver distortion rises with freq. Maggie ribbons have the little dots or flat elastomer segment suspensions to reduce twisting distortion, which is where I guess the bulk of distortion in a ribbon comes from, the rest from varied cavity issues.
Zaph has a collection of ribbon tweeter measurements as well as some speaker parts suppliers.
Trying the 5 inch version as a line source in a garage system. They are the thin towers in the back.I have not heard them yet, but tried just two of them built up on a board. They sounded pretty nice even then.Sorry for the sideways pic
I had a pair of Infinity RS-1b, and now have the ET LFT-8b. The EMIT and EMIM drivers are known to go bad after a number of years, are expensive to replace, and don't imo integrate as well as do the ET drivers (the LFT-8 has a pair of midrange drivers covering 180Hz to 10k, with no x/o in that range). The ET can be bi-amped, the RS-1b must be. And the external x/o that came with the RS-1b was not very well built. I would avoid them.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: