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Exciting new line of fullrange drivers from Feastrex

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Three things seem to have conspired against Exact's future. Perhaps these are inter-related.

1) Mr. Sano is not in the best of physical health.

2) Mr. Sano is not in the best of spiritual health. I'm no expert, but I think he may be struggling with depression.

3) Mr. Sano has lost the support of the people he needs to make Exact a success -- his suppliers and his customers. He owes a lot of people a lot of money, and he has a lot of unkept promises hanging over his head.

He is not without personal culpability, in my opinion, in the loss of the last opportunity to make Exact a success. Poor health and even depression cannot completely mitigate one's liability for making promises that one cannot keep, and for then compounding the problem by not facing up to the truth. His customers and his suppliers gave him every opportunity, and showed him the patience of saints, but he blew it.

The best of the Exact fullranges remain pinnacles of fullrange performance, and nothing can change that. But only a tiny fraction of Exact's potential as an enterprise could be realized. Some of the best Exact speakers from the 1970s and early 1980s will likely never be resurrected. I would have loved to see the legendary 29cm PR-EX, an edgeless fullrange driver that weighed about 30kg (!) resurrected. But I doubt it will ever happen.

Everyone I know who has suffered loss due to Mr. Sano still wishes him well, and are grateful that through him the potential for a higher plane of fullrange performance could come into view. (And I am glad to report that others are now exploring that potential.) But there will be no "next chance" for Mr. Sano. I think it likely that the final sentence in Exact's story has been written.
 
Recent happenings at Feastrex: RMAF & beyond

(Disclaimer: I HAVE NO FINANCIAL INTEREST IN FEASTREX. The following has not been requested or approved by anyone.)

An externally hosted image should be here but it was not working when we last tested it.


Readers may remember that I have been posting off and on over the years about the progress of Feastrex, a new Japanese maker aspiring to make fullrange drivers in a league of their own. This post is just to bring people up to date on activities at Feastrex and their overseas business partners.

First, Feastrex has introduced a new line of 9-inch fullrange drivers that are amazingly good and competely redefine the state of the art. These follow the same basic concepts as the 5-inch drivers, so there are three types: a spherical "Naturflux" motor, a huge traditional motor, and a series of field coil drivers. The field coil drivers are: Type I, all-iron monocoque yoke and face plate; Type II, iron yoke with Permendur pole piece and face plate; and Type III, all-Permendur monocoque yoke and face plate. The naming of the drivers is D9nf, D9, D9e-I/-II/-III, respectively -- following the same pattern as their 5-inch counterparts. The one person outside of Japan who knows these new drivers best is Joe Cohen of The Lotus Group, Feastrex's representative in the USA. Feastrex's Mr. Teramoto carried a pair of D9e-II drivers to San Francisco and spent a few days with Joe Cohen; together they worked on setting up the drivers in the prototype 110-liter bass reflex enclosure that will be used to demonstrate the drivers at RMAF October 12-14. Here are some of the comments that I later received from Joe:

"Sheer heaven. Full powerful and highly detailed . . . Ultimate clarity and purity . . . Ultimate transparency . . . Tremendous and articulate bass . . . The most full wavefront I have ever experienced -- no holes or dropouts anywhere. Anywhere! This is the sound that so many have tried to extract from horns. Some may have come close but I have never before heard the total freedom of effort and lack of coloration evident here. One is able to relax totally into the event and experience the music on the deepest level. The Feastrex Dimension 9e speaker is a breakthrough product. There is no question in my mind that it is the answer to every audiophile's dream. One time, many years ago, I wished that I would one day own the very best stereo system. I now know that can only be possible with Feastrex . . . I intend to promote to the world that this way lies ecstasy." And a few days later he wrote: "The D9e is warming up, breaking in, whatever you want to say. I've never, ever heard anything like this. The D9e defines transparency, is the king of microdynamics and the emperor of inner detail. It operates at speeds not normally experienced by ordinary folk and deals in unlimited space as a sideline. It tickles and warms, but cracks like lightning. It says, 'I am what you didn't even know to ask for, but when I show up, you know what I am.'"

Okay, he's got an economic interest in the products, what else is he supposed to say, right? But there is an enthusiasm and genuine sense of enthrallment in those words that can't be faked, and he definitely speaks for me too. I have heard both the D9e and also the D9 here in Japan, and both drivers are simply amazing. I still have not yet heard the lower priced D9nf, but Mr. Teramoto assures me that it is very much up to par for a Feastrex driver, which means that it is "in a league of its own."

Meanwhile, the representative down in Oz has been making great strides with a loudspeaker they are developing around the D5 monster magnet alnico driver, which they plan to introduce at the Guangzhou AV Fair Nov 30-Dec 2. A rendering of the envisioned speaker can be seen here:
An externally hosted image should be here but it was not working when we last tested it.

As a fullrange purist, the looks don't appeal to me, but I can appreciate the concept behind the speaker, and I suppose if one takes the approach that form follows function, this is what you come up with. I expect there are many people who will be fully comfortable with the non-traditional looks of the loudspeaker, especially if it lives up to the sort of expectations conveyed in this description:

"To say we were impressed is an understatement. I had to practically peel Aaron off the ceiling . . . Perched on top of the bass module and using a less than optimal crossover setting we heard a sound that blew us away. We heard coherency and precision of imaging like vintage Corals, but a much lower resonant signature and a much higher level of clarity. In addition the bass module provided a foundation to the music which was entirely in keeping with the fast, agile Feastrex drivers. Since the Feastrex is providing a point source for the majority of the frequency range the soundstage is amazing. Compression is virtually non-existent since the active crossover Stuart has designed relieves the Feastrex of having to reproduce the lowest frequencies. The bass module is capable of playing 'Woofer Cooker' without any problem at all." And another person at that early session echoed those sentiments: "I was truly blown away by what I heard and that was with a budget CD player as source no less. The sound was so natural and effortless, it instantly reminded me of the first time I heard a live symphony orchestra where the sound doesn't just get louder during crescendos, it also gets bigger to fill the entire acoustic space without a hint of fatigue. This is a loudspeaker that I could live with for the rest of my life and that Feastrex driver is truly a work of art both sonically and visually. It appeals to the perfectionist in me on every level but equally it just makes me forget about hi-fi and fall helplessly into the music."

The entry-level D5nf drivers are also getting some serious accolades. Just a few days ago I read this from a fellow who heard the D5nf drivers that had been unceremoniously stuffed, using adapters, into Hedlund Horn enclosures, which is of course designed for a completely different, larger fullrange driver:

"The D5nf units were just set into a makeshift baffle adapter plate, not fully sealed to the horn. But the bass was still actually OK. I could hear the notes of jazz bass down to about 50Hz, but the body and correct volume was missing at those low levels. [<i>I know from experience that a different enclosure could produce deeper bass. - Chris</i>] Hard to believe they could play so low with such detail and be so small. But then it was even harder to believe the sound of the ride cymbal was coming from a 5" paper cone. Scary real, unbelievable. The driver is fast enough to get the meaty heart of the chaotic harmony of a cymbal more correct than any speaker I have ever heard, including recording studio monitors. I've played trumpet for many years, so I know what it sounds like. Miles Davis' trumpet coming out of these speakers was as real as if he was standing there. The microdynamics revealed every quiver of his lip, he actually sounded nervous, timid, a slow start to his famous So What solo. I know the feeling, and I hate when my own recordings sound that way, although my nerves show much less subtle than his. Hearing so deeply into his psyche and style is a beautiful experience for me. This is a CD of a 1959 3 channel recording, not close to modern digital recordings for detail, and yet there was so much more on there to hear than I knew. I have many such records that need to be revisited with Feastrex. Sarah Vaughn, Julia Fisher, Bill Evans, Trane - it will be a lot of fun!"

Anyway, you get the idea. Feastrex has come a long way in the nearly two years since its debut at CES2006. In fact, the builder, Mr. Teramoto, now looks back on that with considerable embarrassment, because it is now clear that the drivers were far from ready for prime time. But that was then, and this is now. If you heard Feastrex at CES2006 and liked them, you will be amazed by how much they have matured in two years. And if you heard them then and didn't like them, you really owe it to yourself to hear them at RMAF if at all possible, because they are now a much different breed of animal. The Lotus Group will also be demonstrating them at The Show running concurrently with CES2008, so if you aren't going to RMAF, try to catch them in January.

In addition to the D9e in 110-liter bass reflex enclosure, the D5 will be demonstrated in a 50-liter enclosure with passive radiator, also made by Feastrex.

Horn lovers may be interested to know that the representative for France, Madotec, is working on sophisticated, uncompromising horn enclosures for some of the Feastrex drivers. I don't have any more details beyond that.

While continuing to support DIYers, Feastrex is going to start emphasizing complete finished loudspeakers in the future. The entry-level drivers are the only ones that DIYers can afford, and even that is the extreme upper end of the market. The more expensive drivers are unavoidably out of the range of more than 99% of DIYers and the only logical thing is to provide them as finished loudspeakers. The prototype enclosures are nothing exotic, but the loudspeakers that will be introduced commercially in the near future will definitely be aimed at people with very deep pockets, but they will have both the good looks and also the performance content to justify their high prices. This is a business decision that, in my view, makes a lot of sense, even if it means that Feastrex's target market will become more exclusive.

Feastrex's website is better than it had been previously, as far as content is concerned. At least it has been brought more or less up to date. The looks still leave a lot to be desired, but among Feastrex's users is a web designer who has agreed to create a more respectable website for them in the near future.

Okay, that's it for now . . . if anyone hears Feastrex at RMAF, please let me know your thoughts!

-- Chris Witmer
 
No performance measurement data until after RMAF, for the simple reason that Mr. Teramoto bought a speaker measurement system but can't read the English instructions on how to use it. So he and his interpreter will be be meeting with the maker of the speaker measurement system at RMAF and they'll teach him how to use it.

-- Chris
 
frugal-phile™
Joined 2001
Paid Member
Re: Recent happenings at Feastrex: RMAF & beyond

cdwitmer said:
Horn lovers may be interested to know that the representative for France, Madotec, is working on sophisticated, uncompromising horn enclosures for some of the Feastrex drivers. I don't have any more details beyond that.

He also contacted me for Frugel-Horn information wrt the 5" drivers.

dave
 
T/S parameters for the D5nf & D9nf

Well, I'll tell you that I don't really know what I'm doing when I use it, but I do have a simple Woofer Tester Two that I have used to take basic measurements of some of the drivers.

An externally hosted image should be here but it was not working when we last tested it.


Here is what I have for the D9nf:
Revc = 15.0239 ohms
Fs = 63.7892 Hz
Zmax = 242.4445 ohms
Qes = 0.4280
Qms = 6.4784
Qts = 0.4015
Le = 0.8499 mH (at 1 kHz)
Diam = 180.0000 mm ( 7.0866 in )
ConeArea =25446.9030 mm2( 39.4428 in2)
Vas = 22.8764 L ( 0.8079 ft3)
BL = 18.6603 N/A
Mms = 24.7485 g
Cms = 251.5342 uM/N
Kms = 3975.6030 N/M
Rms = 1.5311 R mechanical

(For what it's worth, the D9x series seems to be extremely easy to work with in bass reflex boxes. They have sounded good in a number of boxes that they have been tested in, ranging from 70 liters to 110 liters in volume. Joe Cohen, who is preparing to demo them in 110 liter enclosurres at RMAF, just called me on the phone a few hours ago and told me that the bass he's getting out of those cabinets is "astoundingly deep -- 'right through the floor' -- and incredibly beautiful." Mr. Teramoto and his enclosure maker arrived at the port dimensions by a very scientific method -- they just guessed: "That ought to be about right." It's just a square hole cut in the baffle. When Mr. Teramoto told me, I said to him, "You're going to RMAF and you just guessed at the parameters for the box? You like to live dangerously, don't you." To which he replied that these drivers will produce great bass in just about any box and there's no need to worry about it . . . which appears to be the case.)

An externally hosted image should be here but it was not working when we last tested it.


Here's the same Woofer Tester Two data, this time for the smaller D5nf driver:
Revc = 14.5706 ohms
Fs = 107.8037 Hz
Zmax = 159.5979 ohms
Qes = 0.6515
Qms = 6.4850
Qts = 0.5920
Le = 0.4430 mH (at 1 kHz)
Diam = 105.0000 mm ( 4.1339 in )
ConeArea = 8659.0145 mm2( 13.4215 in2)
Vas = 5.4951 L ( 0.1941 ft3)
BL = 7.9544 N/A
Mms = 4.1769 g
Cms = 521.8188 uM/N
Kms = 1916.3741 N/M
Rms = 0.4363 R mechanical

The D5nf seems to be a bit harder to design an optimum box for, but it has been around longer and there are a few decent designs. Here is a diy rendition of Feastrex's original enclosure, about 33 liters, which is very good when properly set up but not always the easiest to use on account of its dimensions:

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Here is a protoype 50-liter enclosure from Feastrex that looks like it would be easier to use:

An externally hosted image should be here but it was not working when we last tested it.


The passive radiator could easily be replaced by a port, either on the front or the rear of the enclosure. You can note in the photo that the protruding base on the enclosure is removable. I believe it bolts onto the bottom of the enclosure. Of course, it is just a prototype, but probably any box of about 50 liters capacity would work. If I was to do it, I would cut a hole in the baffle that would accept a PVC pipe with a tight force fit, and cut and try different lengths of pipe to find the length that worked best.

I'm certainly no expert, but when I look at the Feastrex enclosures for the smaller drivers, I think they are best described as "4th Order Large Vented Enclosure with Low Tuning" ("Extended Bass Shelf" or EBS). Scroll down this link for an explanation

In any case, assuming Mr. Teramoto is in fact able to learn how to use is speaker measurement system at RMAF, more substantial measurements should not be long in coming.

-- Chris
 
OK here's one idea for the D9nf based on the specs. you gave above. I'm increasingly a believer in the KISS approach, given that I've need numerous complicated cabinets give no better (frequently worse) results than something stupidly simple.

Like this Shadow style box.

Cabinet is 260mm wide x 300mm deep. Upper chamber is 450mm tall (for 35 litres) driver mounted 150mm down from the internal top. Downward firing slot 18mm deep at the rear of the bottom panel, full width of the cabinet, 18mm long (thickness of the build material), feeding a rapidly flared vent 381mm tall at the front. Strike-plate starts 25mm down from the slot. Similar layout to the attached, though the slot doesn't need the extra panel, as it's only the length of the material-thickness, & the flare won't look as skinny.
 

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The doubled box is tuned ~10Hz lower as shown above. As you can see, excursion is no higher than for the single version.

I normally try not to overload threads up with multiple posts of graphs but I wanted to make an exception in this case for several reasons. a) because they're unusual drivers clearly showing a lot of personal effort / artistry involved in their design, and b) as my quiet response to some remarks elsewhere.

I'll look into the smaller unit next. I'd love to do something for the Alnico & field-coil units too at some point. :nod:
 

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