On high-sensitivity (super)tweeters, or, "I musta got lost"

mhardy6647

Señor Member
I’ve never played with super tweeters on my 604’s. I’ll have to give that shot one of these days and see what I think.

Looks like there are several options being discussed that would fit the bill.
The Altec cognoscenti will say "doesn't work; one cannot integrate supertweeters with the Altec drivers successfully". That is probably true -- but, empirically, to my ears, one may get close enough. ;)
 

mhardy6647

Señor Member
Yes, it is, but the cost of that last 5k may be excessive relative to the additional value it would bring.

If one wants to go the true "supertweeter" route, it can be done. The above mentioned R/S leaf tweeters, the venerable R/S/Fostex 40-1310 "bullet" tweeters and most of the modern Fostex supertweeters all have good response to 20k or more.

The response of the aforementioned T90A is good to ca. 25kHz, if memory serves.
https://www.madisoundspeakerstore.com/bullet-tweeters/fostex-t90a-top-mount-horn-super-tweeter/
 

David

Moderator
Yes, it is, but the cost of that last 5k may be excessive relative to the additional value it would bring.

If one wants to go the true "supertweeter" route, it can be done. The above mentioned R/S leaf tweeters, the venerable R/S/Fostex 40-1310 "bullet" tweeters and most of the modern Fostex supertweeters all have good response to 20k or more.

The response of the aforementioned T90A is good to ca. 25kHz, if memory serves.
https://www.madisoundspeakerstore.com/bullet-tweeters/fostex-t90a-top-mount-horn-super-tweeter/
so if i wanna go this route and get this fostex to take care of 15kHz onwards only, I just need to install a cap between the tweeter and my compression driver?
 

mhardy6647

Señor Member
so if i wanna go this route and get this fostex to take care of 15kHz onwards only, I just need to install a cap between the tweeter and my compression driver?
well -- I'd suggest also using a variable L-pad. Adjust to taste, measure Rparallel & Rseries and replace with good resistors for a fixed pad if you abhor the thought of a variable pad in circuit -- or calculate a fixed attenuation and install the appropriate Rseries & Rparallel.

Here's a calculator: http://www.sengpielaudio.com/calculator-Lpad.htm

EDIT: Of course, it could be possible to find a "super" tweeter with an output that matched one's "fullrange" loudspeaker -- but the L-pad's cheap insurance.
 

mhardy6647

Señor Member
For the information of anyone who might be interested, I just got a "back in stock" notice from good ol' Parts Express for the aforementioned B&C DE35 tweeter.

To quote PE's e-mail:
B&C DE35 Neodymium Mylar Bullet Tweeter
Part # 294-580

Due to demand, availability may be limited. To assure you can purchase what you need, please order at your earliest convenience.
:)
 

John Frum

Secret Society Member
My next build is likely going to be an extended midrange 3-way with a supertweeter, so this thread is relevant to my interests.

Hard to argue with the flat response DE35 and its Sino-Brazillian knockoff, especially for what the better Fostex tweeters cost these days. I'm also considering something along the lines of a vintage Pioneer HW-7 or Hitachi. Or maybe the Beyma CP21/F...
 

dowto1000

Junior Member
I am not so sure that a flat response to 20kHZ is necessary. Some professional sound people like a gradually declining response from 12 or 15K to 20K.

See the URL below, go about 40% down the page, commence your reading with " Sound Pressure Measurements ":

http://www.vtaf.com/id107.html

And not to confuse the matter, I have owned / used 7-way speaker systems that measured out to 110 kHZ ( Fulton's P-12 Premiers ), but now run A7-800s at home..

There is one thing I am very sure of, MOST SET amps do not play a good high end at all, in terms of energy with linearity. They almost all, mainly only play a nice midrange. Their high end playback capability is largely " MIA ".

The high end deficiencies we hear from, say, a typical two-way ALTEC speaker system, IMHO, is STARTING right at the audio amp!

Its an AMP problem..... to start with.

The amp is not engineered and designed to play back music wide-band and linearly, energy-wise, in the lows and in the highs.

The problem is compounded by subsequent choices made in amp to speaker wiring, botched crossover executions, and crossover-to-speaker wiring. This is all part of a un-thoughtfully executed audio chain. Amps are the biggest offender.

WE hear the speaker, and our listening room, as the LAST part of the chain, but the deficiency we notice, say in harpsichord playback, is typically due to what is feeding the speaker, all those numerous botched / poor implementations that precede the speaker.

I think, in my own way of thinking, and just my personal opinion, adding a super tweeter is much like putting lipstick on a pig, the wrong place to go.

Thanks for listening to MY opinion. Have fun, I sure do !!

Dowto1000
 
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Punker X

Junior Member
I admit to using Fostex T-90A's, Got them cheap with a pair of DIY speakers. Kept the tweeters and sold the cabinets and other driver.

Did I need them... No was pretty happy without them, both running 604-K's and the GPA's. I do like the little bit of air they ad on the top end.

To each their own... Sure I will get a run down on the deficiencies of my system.
 

billfort

Administrator
Staff member
Sure I will get a run down on the deficiencies of my system.
Ah, no - don't think we will be seeing any more of that.

Super tweeters on 604s has been an interesting side-trip for me. I love 604s and one of the most appealing aspects of them for me is the way they combine the point-source imaging and cohesiveness of a full-ranger with the big dynamics and extension of an Altec 2-way; at least once you get the crossover right. They are like a big Altec 2-way in a better imaging, more cohesive package that actually works in real-world sized rooms.

So I was always resistant to trying add-on tweeters with mine as I felt they did just fine up top on their own and the point source thing...Then I heard a pair of 604E's with some add-on Altec 3000G tweeters on top brought in very high - I think 6db high-pass at 15k with a good cap. I quite liked them and thought I'd try it with a few things I had around like some leaf tweaters, EV TW-35, etc.

Getting the level right was a challenge (it was hard for me to get them to not 'draw attention' to themselves) but I think I got there with the EVs and kind of liked it. After a time though, I took them out and found that I just enjoyed music more without them - I was drawn in more, thought less about what the speakers were doing and more about what the musicians were playing. Kind of weird really, but I just found the 604s without them where more refined - had more 'whole-ocity' - even if they didn't sparkle quite the same.

Never tried something as nice as the Fostexs though, maybe I should someday. I believe my Gs go a little higher than the Es though, which might explain the more pleasant improvement I heard in the Es on super tweeters. I did notice that my friend removed the 3000Gs from his system eventually and said he ultimately preferred the Es straight-up, so maybe it isn't just me.

To each there own for sure, and a very worthwhile experiment.
 

dowto1000

Junior Member
Ah, no - don't think we will be seeing any more of that.

Super tweeters on 604s has been an interesting side-trip for me. I love 604s and one of the most appealing aspects of them for me is the way they combine the point-source imaging and cohesiveness of a full-ranger with the big dynamics and extension of an Altec 2-way; at least once you get the crossover right. They are like a big Altec 2-way in a better imaging, more cohesive package that actually works in real-world sized rooms.

So I was always resistant to trying add-on tweeters with mine as I felt they did just fine up top on their own and the point source thing...Then I heard a pair of 604E's with some add-on Altec 3000G tweeters on top brought in very high - I think 6db high-pass at 15k with a good cap. I quite liked them and thought I'd try it with a few things I had around like some leaf tweaters, EV TW-35, etc.

Getting the level right was a challenge (it was hard for me to get them to not 'draw attention' to themselves) but I think I got there with the EVs and kind of liked it. After a time though, I took them out and found that I just enjoyed music more without them - I was drawn in more, thought less about what the speakers were doing and more about what the musicians were playing. Kind of weird really, but I just found the 604s without them where more refined - had more 'whole-ocity' - even if they didn't sparkle quite the same.

Never tried something as nice as the Fostexs though, maybe I should someday. I believe my Gs go a little higher than the Es though, which might explain the more pleasant improvement I heard in the Es on super tweeters. I did notice that my friend removed the 3000Gs from his system eventually and said he ultimately preferred the Es straight-up, so maybe it isn't just me.

To each there own for sure, and a very worthwhile experiment.

Bill,

Having attended RMAF / Denver each of the last eleven years, I have heard, IMHO, FABULOUS highs from a GPA-604 / MLTL from time to time, certain years. No tweeters added. ( It varies some annually - typically due to a lack of room set-up time ).

It is possible to do, to the Queen's taste, and it was much much fun to experience. I personally have heard it . One big problem is its expensive to implement. The entire chain is part of the equation.

Ditto - last couple of years, on the low end.

Dowto1000
 
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mhardy6647

Señor Member
I admit to using Fostex T-90A's, Got them cheap with a pair of DIY speakers. Kept the tweeters and sold the cabinets and other driver.

Did I need them... No was pretty happy without them, both running 604-K's and the GPA's. I do like the little bit of air they ad on the top end.

To each their own... Sure I will get a run down on the deficiencies of my system.
There are some strong opinions floating around about how hard to impossible it is to add 'supertweetage' atop 604s (or Altec treble horns in general) but I, too, thought that the T90As, crossed in very high & suitably padded, added value rather than subtracting it on my 604Es/Mastering Labs XOs (FWIW).

I am using the aforementioned B&C bullet horns with the current 'Frankenaltec' and I like them. They're less polite than the T90As (and very sensitive, perhaps even moreso than the T90As) -- again FWIW.
 

dowto1000

Junior Member
Mark,

From the photos you have posted for us all, I would say your conclusions make a great deal of sense, that a tweeter is a positive for you. No doubt.

Audio-wise, we need to consider these three following things :

Can any single 20 uF film cap play a top-end adequately, all by its lonesome self??

Can the wire comprising a clip lead, and a clip lead's unsoldered connections, play a top-end ??

Can a crossover's pad-down POT require some sort of small value film bypass, to restore energy lost across it, to the tweeter section??

Dowto1000
 
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TubeHiFiNut

Administrator
There are some strong opinions floating around about how hard to impossible it is to add 'supertweetage' atop 604s (or Altec treble horns in general) but I, too, thought that the T90As, crossed in very high & suitably padded, added value rather than subtracting it on my 604Es/Mastering Labs XOs (FWIW).

I am using the aforementioned B&C bullet horns with the current 'Frankenaltec' and I like them. They're less polite than the T90As (and very sensitive, perhaps even moreso than the T90As) -- again FWIW.
I have been reading your "Frankenaltec" journey with great interest and enjoyment. It has inspired me to experement with a variety of 500hz and 800hz horns (still gathering the drivers so no results yet) and now your super tweeter writings prompted me to dig out the Pyramid T1 ribbons and start gathering additional tweeters (Calrad horns, for starters) to see what kind of fun I can have.

That really is the key, IMHO.....having fun while we partake in our hobby.

Thank you, Mark, for sharing this journey. :)
 

Punker X

Junior Member
Always one to subscribe to "KISS".. So disconnected for the Fostex for a while. I'll get used to it for a few days then hook them back up and see what my ever evolving thoughts are
 

mhardy6647

Señor Member
recent chatter re: the Altec 3000 (which Altec said, sans horn, was "only -25 dB at 100,000 Hz"! :biggrin:) reminded me of some discussion, years ago, at AA on the venerable Radio Shack 40-1310 (Fostex) bullet "super tweeter". Unlike some (most) drivers that ol' Marky's nigh-on sixty year old ears would consider supertweeters ;) the R/S drivers really were -- that claimed "ultrasonic response" in the R/S catalogs was legit!

Here's the story, from Bottlehead's Paul Joppa, posted @ AA and reproduced here for posterity :)

https://www.audioasylum.com/forums/hug/messages/9/98637.html

Posted by Paul Joppa (P) on December 16, 2005 at 10:34:2
In Reply to: Re: Connecting a supertweeter posted by Godzilla. on December 15, 2005 at 11:54:36:

Just a note to confirm that the published response is in fact accurate. Back in my former life, we used them to generate high frequencies (up to 40-50kHz) in a traveling wave tube. A colleague told me about them. We had been using the small Altec coaxial - the 1" dameter voice coil dome with attached fake-sectoral horn. The Altec had less extension, was prone to burnout - it was also used as a dynamic mic diaphragm - and replacement parts were hard to find, so we switched to the RS. I've measured them in the large anechoic chamber with calibrated 1/4" instrumentation mics, and the gentle smooth rolloff to beyond 40kHz is real even with an unsmoothed FFT.
At least when we got them, there was a built-in 6kHz second order crossover with a ferrite core inductor and a cheesy NP electrolytic cap.

Incidentally, we also checked out the EV DH3. It's much more rugged than either of the others, but drops fast above 20-22kHz - there's really nobody home at 30kHz.


source: http://diyaudioprojects.com/Drivers/40-1310/40-1310.htm
 
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