[chrisby]

For consideration...............

http://www.ejjordan.co.uk/basics.html

I am liking the questions so far.

Dave, don't doubt it a bit. So does a Bandor (which will play to a 100hz easily)...and a lot of others, now, name the 6 incher that "rivals a big buck tweeter"? Not a trick question, but rather "for real". I want opinions! It's "nice" we are in "agreeance" (I love that fake word).

Ed

well, if price can be ignored, then perhaps a Feastrex ?   

[floobydust]

well, if price can be ignored, then perhaps a Feastrex ?   

 Yes, I have to agree... a Feastrex is an excellent choice.

 Regards, KM

[Ed Schilling]

I have no response to using a Feastrex as a tweeter. It does not seem within the realm of practicality but if you guys say it will work I believe you.....now, exactly what is the mms of a Feastrex. I am betting its a LOT less than 10 grams and I never bet. I honestly don't know. Will try and find out after I post this.

Still on track.

Ed

[Ed Schilling]

Ok,
No info I could find quickly....except.......  35-23K (-10db for a 5nf

If that -10 is at 23k then it is no tweeter regardless how it "sounds", I think. But that is not the point. It has been "nominated" as "possible". Let's see if there is a reason why it may actually make a good 6 inch tweeter. OOPS.....how big is it? Were you guys talking about the 5 or 9 inch?

Still would like to see mms, just for curiosity sake. And I am NOT knocking the opinion of this driver or saying it isn't what it is said to be.

So far so good....

Ed

PS...please don't tell me the 126 is -10dB at 23k too.....this is not about "it"!

[DaveC113]

Feastrex have whizzers, thats a whole 'nother ball of wax I think (mechanical x-over)....

[Christopher Witmer]

FWIW the cone assembly (including voice coil and surround) of the Feastrex 5-inch drivers has a moving mass of under 3 grams . . . under 8 grams for the 9-inch drivers. It varies slightly from model to model, and since they are using natural materials (e.g. leather) there is some variance within any given model as well. (The effects of that latter aspect are minimized by always working with drivers in pairs, even, for example, in a reconing situation, despite the fact that overall consistency over time is actually quite good . . . )

As Dave pointed out in the post above mine, the whizzers do complicate matters . . . if their mass is considered separately then one is actually talking about a still much smaller mass.

And that's not all, because from the way the drivers function it seems reasonable to speak of them as having a mechanical crossover such that the highest frequencies are produced directly by the voice coil/voice coil former, with the whizzer cone contributing over a very broad range (although I'm not sure just where its contribution begins and ends) and the lowest frequencies by the main cone (again, with the main cone also reaching up pretty high).

Of course, what I just described is hardly unique to Feastrex and probably applies to all whizzer drivers to varying degrees . . . Feastrex's claim (which I'm prejudiced toward believing despite having limited experience with other brands) is that they do a better job of balancing all the elements into an organic system, and I think there is also a clear implication that the choice of materials somehow makes for inherently more pleasing sound reproduction . . .

Of course, even if it be accepted that the Feastrex drivers do a better job as fullrange drivers, the price is the price so it would be a serious problem if one wasn't getting some sort of a performance advantage for all that additional expense.

A Japanese gentleman posting under the name "Bunpei" over at DiyAudio recently reported about his experience with the top-of-the-line 9-inch field coil driver, with a motor milled entirely from a single piece of Permendur:

I could enjoy the 9" Exciter with Permendur motor (Type III) this afternoon. I'm neither a professional critic nor an industry observer. Even for a just an amateur like me, the breakthrough the product had established in the history of full range units was apparent. Superb resolution in the high range is far beyond the conventional standard level for full range. If you were exposed to the sound blindfolded, you might identify the sound as being generated by a tweeter or a super tweeter. However, actually there you find only a full range unit with paper cones of 9" diameter. I could perceive a lot of new detail in the musical performance. Especially the unit has an unbelievable capability of reproducing tones emitted by metal musical instruments such as cymbals as well as percussion instruments that contain highly transient components. The sound reminded me of the fact again that a piano or harpsichord sound is produced by steel wires. The units were set in the existing enclosures shown in the pictures posted by Chris. [An experimental enclosure -- Chris.] I felt the balancing of the low range against mid and high was not pursued far enough in the current enclosure setting. Obtaining an adequate low range performance from this unit might require the help of an enclosure designer rather than a unit designer.

*Edited very slightly to improve readability.

One person's entirely subjective opinion, to be sure, but that's awfully high praise for the treble performance of a 9-inch driver. On the other hand, what else could we expect given that even today one can probably purchase a nice home in some communities in the USA for what one might pay for a pair of these drivers? Be that as it may, when the 5-inch version of any driver is compared side-by-side with the 9-inch version of the same driver, one can hear that the 5-inch drivers do have a slight advantage over their big brothers in reproducing the highest frequencies.

-- Chris

[Ed Schilling]

Thanks Chris,
Soooooo........under 3 grams for the 5" and 8 for the 9". That is what I thought. the Feastrex is NOT a 10 gram, 6 inch tweeter.

Fostex 166E.....6 inch....6.8 grams
Feastrex    5 inch..........under 3 grams

Fostex 208 E Sigma.....13 grams (no whizzer)
other 8 inch fostex......~15 grams
Feastrex...................~8
Hmmmmmm..........I bet the high end on either Feastrex is "better" than any of these Fostex which have comparable cone sizes.

I sure hope no one thinks that I think that this (low mms) is "all there is to it".

Now, how many times have we heard....."the 208 Sigma sounds better when used with a "super tweeter"?" Got news for you,
it is the response above 8k that needs help, not above 20K (real super tweeter territory in my book) since there is no program material above that possible on CD.   But that is another whole discussion. Been there, proved that.

So here we are...Feastrex nominated and coincidentally it has a VERY low moving mass. How about that, who would have thought? Me.

And the 5's are a little "better" than the 9. I wonder if it is the lower mms and smaller cone diameter? I wonder if somehow you could get  similar efficiency without increasing excursion of the driver and similar bass response from the 5 that it would not better the 9 in all respects? How could that be done? Is it possible?

Questions, questions, questions, the kind that might make a guy spend years fooling with single driver speakers.............thanks for playing guys....but we got a long way to go.....

Feastrex is done.....are there others?

Ed

[Graham Maynard]

So Ed -

Re: "the case against a 10 gram, 6 inch tweeter...."

- the case against has not been established, this as way of proving its usefulness.

6" cone or 6" chassis ?

My suggestion is that the cone must be 6" in order to encompass the human voice range without too much cone excursion or the passing of male chestiness over to another driver.

Whizzer cones will prevent the acoustic centre from retracting as much at HF (phase lag), but ultimately they can introduce reflective cavity shapes.  (Phase lag also being what a supertweeter can help correct.)

Cheers ......... Graham.

[Christopher Witmer]

By the way,thanks for starting this very interesting thread.

Definitely, at least when a shallow crossover slope is used, any super tweeter is going to be making its presence felt down pretty low . . . I think my ears are pretty much shot over 16kHz but I can hear a supertweeter that is crossed around 16kHz . . . I bet I'm hearing it down between 8kHz and 4kHz (the latter being the very top end of the piano . . . it's funny how to my mind the very top end of the piano conveys the impression of a fairly high pitched sound but actually it is "only" 4k).

-- Chris

[miklorsmith]

I wonder if somehow you could get  similar efficiency without increasing excursion of the driver and similar bass response from the 5 that it would not better the 9 in all respects? How could that be done? Is it possible?

Questions, questions, questions, the kind that might make a guy spend years fooling with single driver speakers.............thanks for playing guys....but we got a long way to go.....

Let me shorten the trip.  Treble is better with a small driver, let's just close the loop on that.  So, how to fill in the bass with less inherent driver energy?  Put the 5 in a REAL BLH, not the fake-o ones everyone seems to be selling these days.  Then put it in a corner, a REAL corner to fill out the bass response and "complete" the horn mouth.  Lots of designs have been built over practically millennia and this design unequivocally is the best in all situations to the point where trying anything else is folly.

[Ed Schilling]

Graham,
The subject can just as easily be "disproved" if that is where we are led. Your opinion on a 6 inch cone needed for human voice is interesting. B&W uses a large midrange driver......a light midrange driver. And a tweeter in every case.

Chris,
Yep, that is what happens when most add a "super tweeter".

Msmith,
Nice try, but that is NOT where I am going. And it may take weeks to get there....after all, how long have single driver speakers been used and what makes them "special"? When did "improved drivers" emerge and what makes them fundamentally different enough to justify their existence? The cone driver has not changed too awful much in the way it works.....glue is better, but other than that, most of the technology is "old". Why until the last few years did people decide that "bigger is better" for single drivers when speakers in general all started as single driver systems? . Have they increased cone size at the expense of high mass and therefore caused a loss of "something"? Is it possible this "something" is what makes single drivers so attractive in the first place?

Maybe the loss of this "something" pushes them toward conventional sound and away from what makes a single driver "special"?

Is that the "goal" of a single driver system, to sound like a full range pair of Advents? To image like a pair of Webcors?

I wonder, since a single driver is such a good thing, how come multi way speakers came to dominate?

I wonder what makes the "really good ones".....into really good ones.

So far, it seems the lowest mass coupled with the most surface area is desirable, and this applies to "the best sounding" that we have hit on......does anyone disagree?

MSmith, don't be so cynical.......if I was going to push a design or something I wouldn't be asking, Id be telling! You know that, you have read my posts and are well aware of my bias!

I have NEVER, I repeat, never said......"Lots of designs have been built over practically millennia and this design unequivocally is the best in all situations to the point where trying anything else is folly."

Mainly because it's not true in every case.....it's just "one way". One of my favorite drivers, the Bandor, will only work in a small sealed box, for instance.
 
 But again that is not the point of this post. I am not concerned how people load the driver.

Ed
*edit*...crap, I hit "post" by mistake!

[miklorsmith]

I think large multi-ways and their resulting inefficiencies became vogue when SS power became cheap and designers realized that true full-range performance was possible in a WAF-sized box.

I think the basic question of "how good a tweeter is a single driver" is a bit misdirected.  Music isn't built on the high frequencies.  There's little doubt that just about ANY dedicated tweeter will kill just about ANY single-driver speaker in the treble.  That's missing the point of a SD in the first place - build from the mids and work your way out from there.  I absolutely LOVE the guitar tone from my 8" hemps in a BR box and they're pretty balanced speaks that can crank.  My Zu Def. 2s have their dual 10" sealed widebanders augmented below 100 hz and above 12 khz but they still sound like single drivers, with 7 drivers per side.

To me the better question would be "what sized driver offers the fewest compromises, what are they, and what cabinet emphasizes their strengths".

[Ed Schilling]

Msmith,
Close but NO! Multiways came along WAY before SS became common.....KHorn, for instance. And most console stereos.

You are correct about the size of early speakers in general....that was the first slip on the slope.....trying to get big box performance from a small box. I wonder how that turned out?

A large multi way BTW will/can be a very efficient device....provided low mass (oops) high efficiency drivers are used. Cone area vs. excursion. My vote is for ALWAYS lowering excursion. There are only two ways to do it.....increase area or, hmmmmm, I am NOT going to say it!

Early systems had little excursion and lots of area....contrast that to today. The exact opposite is the norm.
What else was "the norm" with early drivers? Hint....small VC's, paper cone, rigid paper or cloth surround?

Ed
*edit*...it's raining today......

[Ed Schilling]

Msmith,
We can go that route too............

I agree, I bet guitar does sound sound through a 8 inch single driver.....it should and if it didn't that would be a very serious problem! The Zu are not even close to a single driver the extra drivers free the 10 inch from every major drawback in a true single driver system....the region below 100 and above 12 (wanna bet a LOT of output is being generated at 6-8K?).

I do not doubt they can sound like a single driver.....the critical midrange is responsible for that......sound begins to lose directionality below 100 hz and the tweeter is needed to eliminate beaming of the 10. Good sound design. A "widrange, large midrange" is not uncommon. But again, look at mms of that 10 inch....anyone care to guess what it might weigh? I have no idea. My guess is, "not a lot for it's size". Again think B&W 803.

Zu Makes perfect sense and I agree with the Zu concept......more so than a heavy 8 in a BR box. Which system does the most things the best? Output, extension and efficiency.......the Zu should rule.

Hey, I like multi way too!

Ed
BTW.....a cap or a coil either alone or used together is a crossover.......any idea the slope on the Zu tweeter? Unless it is very steep there will be considerable output of the tweeter into the midrange.

[Graham Maynard]

Increasing the area - 10" - 12" etc. normally leads to increasing the voice coil diameter.

One of the best sounding drivers I burnt out was 12" with circular ribs, a 1" voice coil and a 2.5" whizzer.

Inceasing the voice coil diameter impairs dome radiated HF and radiation pattern.

Also a voice coil which is underhung can reproduce more HF detail(>10kHz) than one which is overhung.

I still have a single old salvaged 10" and 1" voice coil which sounds good but still needs tweeter for real highs, this because of the increased HF phase change and roll-off with increased curvilinear depth.

The Bandor has less acoustic centre shift.  The Jordan 92 does very well too, though maybe the centre of his cone could be slightly more convex ?
I don't like the inefficiency of these types though.

My Eminence/Fane type 10"ers have typical mms of 20g.
Cap + coil for Zu, above 12kHz if memory not failed.

Cheers ........ Graham.

[miklorsmith]

I actually have a number of in-room measurements.  They don't separate the supertweeter but they show a very smooth response in the 6 khz+ area.  Zu lists the XO point as 12 khz, no slope specified.  6 khz is only one octave below that so it's reasonable to think there's overlap there.

With 7 drivers per side, they clearly aren't SDs.  But, the mains have NO FILTER in them from the amp.  The bass circuit is wholly separate all the way from the preamp and the supertweeter is on a hi-pass filter off the main.  Despite the outward complexity, at the heart they deliver the SD sound and add to it.  Honestly this philosophy is what drew me to them and they have executed the idea incredibly well.

The point I'm making is there are many ways to skin the cat, and focusing on one element of a SD like treble only misses the forest for the trees methinks.

[Ed Schilling]

Graham, MSmith,
Agreed. For the most part.

If there is no filter on the main drivers and the ST has a 12k point there is a crossover on the ST but not the mains......
This is still a 2 way and many systems are built this way. We would call that a "mechanical crossover" on the mains or at least that is what some call a woofer "running free" to it's upper limit.
 
This is a 2 way with a 12k HP of unknown slope with a powered built in sub system. I can't see how it could be called anything else.
Which is fine by me.

Ed
PS.....gotta leave for a while..........

[miklorsmith]

This is a 2 way with a 12k HP of unknown slope with a powered built in sub system. I can't see how it could be called anything else.

I'm not one for titles.  The simple fact is they deliver the single driver ideal in spades.  How?  By embracing what SD does well (high efficiency, coherence, tone, dynamics), implementing that, then utilizing minimally invasive strategies to supplement the ends.  They are still single drivers at heart and sound more like my actual SD hemp 8"ers than different.

If we're counting mechanical crossovers, you could say they're 4-ways - bass bins, mains, WHIZZERS, and supertweets.  By this definition even a whizzered driver is a 2-way.

[sts9fan]

The Zu is a simple high pass

[DaveC113]

A large multi way BTW will/can be a very efficient device....provided low mass (oops) high efficiency drivers are used. Cone area vs. excursion. My vote is for ALWAYS lowering excursion. There are only two ways to do it.....increase area or, hmmmmm, I am NOT going to say it!

Early systems had little excursion and lots of area....contrast that to today. The exact opposite is the norm.
What else was "the norm" with early drivers? Hint....small VC's, paper cone, rigid paper or cloth surround?

Ed
*edit*...it's raining today......

I'd throw in the fact that the best SD drivers available right now, IMO (Feastrex and Omega Hemp Drivers) actually have quite a bit of excursion. Another guy who lives close to me has the Feastrex d5nf, and the excursion capabilities of that driver would be considered extreme... I'm guessing well over 20mm peak to peak. My jaw dropped when I saw them playing a drum track at higher volumes. My Omega XRS also move quite a bit, but probably about 1/2 of what I saw the Feastrex do. Again, IMO, these drivers are a pretty big step beyond the Lowther and Fostex drivers I've heard (which are limited, I haven't heard everything under the sun) that feature much lower excursion limits. And they work just fine in a big vented box, horn loading a driver with that much excursion would require a redesign of typical compression chamber so it doesn't stifle the driver. An example is the Maxxhorns, which were re-designed specifically for the d5 monster alnicos. Can't wait to hear those at RMAF this year...

Dave