Good tweeters to cross low, at most 1500 Hz

otto88

Member
2007-12-05 10:39 am
Hi,

To cross to a Seas Excel mag cone midwoofer, whose performance should be great up to 1000 - 1200 Hz, when cone effects start to become evident, I'm looking for tweeters to cross low, at 1500 Hz or maybe less.

Options to cross low, from http://ldsg.snippets.org/sect-7-tweets.php#TWEETS-3/4

Hiquphon OW1 Fs 850 (or 650?), Xmax a big 0.9 mm c $110 each

Seas 27TDFC Fs 550, Xmax only 0.25 mm. only $30

Morel ferrofluid MDT20, or 22: Fs 650, Xmax 0.5 mm. only $33 (eg from Zalytron)
http://ldsg.snippets.org/vendors/morel.php

Human 002M: Fs 1300, but Xmax a whopping 1.5 mm. only $48

Scan Speaks seem pricey, Usher wont cross that low.

Another Seas or a Vifa??

What do you recommend?

Thanks
 

BHTX

Member
2006-02-16 10:49 am
otto88 said:
I'm looking for tweeters to cross low, at 1500 Hz or maybe less.

For crossing that low, horn loading or waveguides are probably the only real possible option, and even then, I think that's still probably pushing it a bit. Regardless, these designs of course create another whole set of obsticles, adding difficulty to the design. Other than that, you're looking at compression drivers, or some other entirely different technology all together, which would obviously change the whole project and design goals (i've never heard of pairing a pro compression driver with a Seas Excel midwoofer, lol). On the other hand, I'd be looking at widerange planar transducers if I were you. BG Neo8 or Neo8 PDR comes to mind. Highpass it as low or high as you want, run it dipole if you want, lowpass it to your tweeter of choice at 7-10 KHz, or whatever you want. You might already be aware of all this though. I just don't think you'll ever find what you're looking for in any small soft dome tweeter for hi-fi. Sure, there's quite a few that CAN do it, but I'm sure it'd definitely require some effort no matter what, and even then, I don't think any results obtained would be considered anywhere near optimal. Distortion sets in, limited SPL, dip in freq response at the xo point, etc etc.
 

BHTX

Member
2006-02-16 10:49 am
Ed LaFontaine said:
Seas TBFC/G H1212 (metal dome)
Seas also has "waveguide" tweeter that Madisound will be stocking shortly...

This one, right?
http://www.seas.no/images/stories/prestige/pdfdatasheet/h1499_27tbcd_gb-dxt_datasheet.pdf

..I agree. It does look very doable with a steep slope.
I guess it's just a personal thing that 1.5 KHz from a 1" dome tweeter just doesn't seem right to me. I've never tried it myself tho, so I can't really say. I'd definitely be interested to hear about it when it's finished, regardless of which tweeter you end up using. Goodluck. :)
 

otto88

Member
2007-12-05 10:39 am
Thanks for all the suggestions

I had in mind a 4th order crossover, but might do a 6th order an/ or cauer-elliptic. .

Seas seem to have most of the running for this .
I’ll look further into their H1212 (specs sound very promising), the T29MF I haven’t found yet . .

For this application, I didn’t want to go to the cost & complexity of compression drivers. (I’ll try one in another room system, when the slow boat arrives).
I know Linkwitz’s Orion, but the Millennium is way above budget. I’d go to $100/ driver, but prefer less.

The Neo8 will go nice and low, but I want something that doesn’t need a super tweeter. Hmm, though I do have some small ribbon super tweeters of similar sensitivity (somewhere) . .

North Creek I think is a good brand (who sells North Creek D25s?)

The midwoofers I have are W17 E002's (though I might use some Focal 6W 4311B's I have).

At least as important a reason for crossing low (as operating the stiff cone materials as far as possible in the piston range) is to maximise dispersion in the upper mids, in a wide open area.

Have searched but can’t yet see anything on the upcoming Seas waveguide tweeter Madisound. But generally Seas are very good, and two of recommended it (wins by one!).
I know some things about waveguides, but how can they assist a drivers low end usability? And where did you hear about it, a Madisound flyer?

Thanks
 

otto88

Member
2007-12-05 10:39 am
> 1.5 KHz from a 1" dome tweeter just doesn't seem right to me

Linkwitz has said that he
“always crosses his tweeters around 1.5 KHz with 4th orders(both the Orion and the Phoenix do) . . with more expensive drivers .

The Seas 27TBFCG:
John at http://www.zaphaudio.com/tweetermishmash/ is very keen, but the FR begins to decrease at 2 kHz, higher than i'd prefer.

In Zaph’s Battle of the Non-Domes, the Neo8’s little brother Neo3 was the best, if not liked as much as the cones . .
 

otto88

Member
2007-12-05 10:39 am
Found the Seas specs page. http://www.seas.no/index.php?option=com_content&task=view&id=90&Itemid=114


The 27TBFCG wrap from John is great for a $30 driver
"Very smooth response, down a few dB at 20 kHz.
Very low distortion of all types, particularly the near non-existent high order harmonics.
No notable energy storage problems." . .


The Fs of the 29TFFW at 950 Hz appears too high for this. Though
Seas state "Flexible lead out wires allow this driver to be used with low crossover frequencies"; and its flat a few 00 Hz below the 27TBFCG

:xeye:
 

otto88

Member
2007-12-05 10:39 am
Mmm, the 27TFFNC while Fs is 1170, only drops below 90 dB at about 1100 Hz, and has Xmax of 0.9 mm . .

but "The voice coil is immersed in magnetic fl uid" - is that basically ferrofluid? aka loss of detail, ie the trade-off . .

I think I'd rather a higher Xo than ferrofluid
 

peter_m

Member
2007-05-14 7:33 am
Well, zaph has useed the 27TBFCG as low as 1450hz and he was happy with the results. Since the 27TDFC is the same construction, just different dome material, should also do the same. Keep in mind that you will not be able to drive it as loud as if you used a higher x-over frequency but it is possible. http://zaphaudio.com/BAMTM.html

Other then that the Seas 29TFFW looks like a better option since it has lower distortion, flatter response and a lower Fs then the 27TFFNC.
http://zaphaudio.com/tweetermishmash/

Ferrofluid or not, I would not worry about it. If it's designed properly, it will sound good. Ferrofluid also is used to increass power handing.
 

otto88

Member
2007-12-05 10:39 am
Though it’s close, I probably do agree with Zaph’s interpretation that overall the 27TBFCG has better test results.
at thsi stage, mixing and matching components is beyond my modest skills & time.

I can wait a month or two - where was the source on the upcoming Seas waveguide tweeter?

Thanks