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

mhardy6647

mhardy6647

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OK, so all who know me know that, when it comes to hifi, I tend to be -- shall we say -- parsimonius. Frugal. Cheap. Yeah. Cheap.

Always looking for bang for the buck.
And often looking for extended treble response for my now 59-year-old ears to top off the big(gish) horns and drivers much enamored by -- some of us.

Having mentioned (perhaps ad nauseum) the B&C neo tweeters here (and elsewhere), I was reflecting on a pair of those "nine dollar" (actually $9.88 apiece) Pyramid "bullet" tweeters that AK member LexDM3 brought up here one cold winter day to A/B with the Fostex T90As. The aforementioned Pyramids acquitted themselves rather nicely to both of our sets of ears (although neither of our sets of ears are what you'd consider reference quality any more!).

Perusal of (even) PartsExpress's "horn loaded tweeter & midrange" selection shows a plethora, nay, a bevy of candidate cheap, sensitive tweeter options :)

https://www.parts-express.com/cat/horn-loaded-tweeters-midranges/35?N=22405+4294967118&Ne=10166&No=0&Nrpp=16&Nrs=collection()/record[endeca:matches(.,"P_PortalID","1")+and+endeca:matches(.,"P_Searchable","1")]&PortalID=1

270-125_HR_0.jpg

270-125_ALT_0.jpg

https://www.parts-express.com/pyramid-tw44-heavy-duty-titanium-super-tweeter--270-125

http://audiokarma.org/forums/index....er-something-else.775780/page-2#post-10648972 (this thread contains a typo - other posts make it clear that the tweeters in question are indeed the TW-44). Needless to say, a higher XO with a better capacitor would be the audiophile-approved way to employ these Pyramids (i.e., capacitors that probably cost more than the tweeters themselves!).

Perusing that PE laundry list above turned up these from PRV, which appear suspiciously ;) evocative of the B&C bullet tweeters that (ahem) started this discussion.

https://www.parts-express.com/prv-a...gh-power-mylar-bullet-tweeter-8-ohm--294-2804

They're a bit cheaper than the B&C DE45 and they're in stock. Neodymium magnet and mylar diaphragm -- like the B&C. Zero experience with these, but they seemed worthy of mention.

upload_2017-10-30_9-25-36.png

So -- this is meant to be a discussion not a soliloquy, so thoughts, counterpoints, and other suggestions are more than welcome! :)
 
Not exactly cheap....my favorite tweeters are the Pyramid T1 by Richard Sequerra.

Also had pairs of the Decca Ribbon tweeters and the Heil AMT - both of which I foolishly sold.
 
The one problem I see is that while the PRV's are just bullet tweeters, the Pyramids are actually Super Bullets. Says so right on the front.
 
I would very humbly and kindly suggest, If SET amps used multiple film cap bypassing bundles, in ALL the SET amp's cap positions, as Marzio and Jelasi rudimentarily did in 1994, they would be able to play the high end more linearly, and the SETs you hear will not just be midrange - centric amplifiers.

It takes lotsa money and good taste, to implement this properly, and there are some people out there, in audio land, that do this.


Dowto1000
 
I’ve wondered about having a super tweet to cover 15k-20kHz region. Add a cap betwen the ST and the HF units of my horns is all it takes? Can the conbo be driven by 2W SET?
 
David said:
I’ve wondered about having a super tweet to cover 15k-20kHz region. Add a cap betwen the ST and the HF units of my horns is all it takes? Can the conbo be driven by 2W SET?
Click to expand...
It can with an appropriate tweeter (triple-digit sensitivity). Flat I don't know about -- although if I (ever) get suitably motivated, I may take some measurements... I (at least in principle, and at a rudimentary, hobbyist level) have the technology.
 
mhardy6647 said:
It can with an appropriate tweeter (triple-digit sensitivity). Flat I don't know about -- although if I (ever) get suitably motivated, I may take some measurements... I (at least in principle, and at a rudimentary, hobbyist level) have the technology.
Click to expand...

as long as it don't drop bad i could EQ the response close to flat.

but most compression HF units drop badly from 10k-15kHz.
 
David said:
I’ve wondered about having a super tweet to cover 15k-20kHz region. Add a cap betwen the ST and the HF units of my horns is all it takes? Can the conbo be driven by 2W SET?
Click to expand...

As @mhardy6647 states, if you want to add the super tweeter with just a cap to act as a high pass filter, you either have to match efficiencies or (if the tweeter is more efficient) add an L-pad of some sort to "tame the tweeter".

Probably better if the tweeter is slightly less efficient so you can keep the impact more "subtle".

Just the opinion of an inveterate tinkerer. ;)
 
TubeHiFiNut said:
As @mhardy6647 states, if you want to add the super tweeter with just a cap to act as a high pass filter, you either have to match efficiencies or (if the tweeter is more efficient) add an L-pad of some sort to "tame the tweeter".

Probably better if the tweeter is slightly less efficient so you can keep the impact more "subtle".

Just the opinion of an inveterate tinkerer. ;)
Click to expand...

that's actually a good idea Tubey
 
I did the 'slightly less sensitive' trick with the venerable (and very, very sweet sounding) Radio Shack 40-1375 "leaf" tweeters. Kinda worked for the "A" variant Valencias I had, but not enough oompf for the Duplexes.

40-1375 by Mark Hardy, on Flickr

upload_2017-10-30_18-31-30.png
(note the sophisticated time alignment of the supertweeter, imaginatively coupled to decidedly unsophisticated control of reflection ;))

These were replaced, ultimately, with a nice pair of Fostex T90A supertweeters sourced from Redboy Audio Supply in America's great Midwest -- and more recently with the aforementioned B&C not-so-super bullets.

My current supertweeter (so to speak) XO modules consist of a 1 uF (if memory serves!) Sprague Atom capacitor & an 8-ohm variable L-pad, installed in a meticulously crafted box; the box having been precision moulded from space-age polymeric material carefully chosen for its optimal resonance properties in the audio passband. ahem.

075 by Mark Hardy, on Flickr

;)

a peek behind the curtain :)

IMG_0341 by Mark Hardy, on Flickr
 
TubeHiFiNut said:
@mhardy6647 - I see you still have the "audiophile approved" clip leads in there. ;)
Click to expand...
No, actually, that particular XO was boxed up and is shown in the photo above the 'clip lead' pic. It's the one in the space age polymer casing ;)

When the weather turns bad here for good I am gonna finalize the Frankenaltec XOs and reclaim some clipleads for other tasks! The one wrinkle with the Franken-XOs is that the inductors on 'em are -- umm -- sorta -- not mine, technically speaking :P

DSC_9642.JPG
 
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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.
 
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