Eighteen Sound XT1464

[BHTX]

Been looking at this waveguide for a little while now. Who all has used it, how did you use it, etc?

I saw that Lynn Olson bought a pair a while ago, but couldn't find any posts in regards to using it.

Also, I found plans for a fairly simple project using the XT1464 with the ND1460 and 15W700/15ND830. With several modifications/improvements, I'm thinking a project using these drivers might actually be pretty decent, with several key benefits and interesting characteristics.

Upon closer inspection, the dispersion of the 60 x 50 degree XT1464 does indeed appear to match best with a 15" woofer crossed at roughly 1.5 KHz. I know some people (most?) are against the thought of using a 15" driver that high, but I've honestly never tried it. I think it's often a matter of taste/opinion/religion/whatever, just like anything else, since it can obviously be done quite successfully. My main concern with such a design is the response of a 1.4" CD above 10 KHz. Attempting to integrate any kind of super tweeter into something like this might turn out to be a real pain. I believe this has also been discussed in Lynn Olson's (long and still growing) thread.

Anyway, either of these previously mentioned Eighteen Sound woofers (15W700 and 15ND830) would work well in 5-6 cubic feet tuned around Fs, and perfect for the usual 2nd order highpass at 50 Hz from a receiver/processor for integrating with subwoofers (btw, this system would be used for both music and theater, if that's not already obvious). And, they appear to do fairly well with the XT1464 at the 1.5 KHz xo point. I am a bit concerned though about the use of a narrower coverage horn and the effects it might have on the sound..

http://www.speakerstore.nl/index.php?pg=11&c=57
http://www.speakerstore.nl/construct.../18s_kit15.pdf

http://www.eighteensound.com/index.a...roduct&pid=177


Also, this larger 1" horn from SUPRAVOX with a B&C DE250 looks rather interesting as well. Very narrow vertical coverage though. I'd be interested in hearing from anyone who's had experience with this horn as well..

http://www.supravox.fr/anglais/haut_...av_1_pouce.htm

[tinitus]

I will use a 1" CD with an 8" mid and an 15" AE woofer and fore this the small 18sound 1086 waveguide may do ok

I am not sure this 2way 18Sound "kit" will be very pleasent to listen to, but more like a party speaker

[BHTX]

The XT1086 appears to start losing directivity pretty quickly below 2 KHz. It also doesn't look near as smooth. The profile doesn't look so great either. It appears to have a diffraction device at the throat. I don't see how that could be acceptable.

As for that Eighteen Sound design being limited to an unpleasant "party speaker", my build would likely be much different.. An active floorstander, and perhaps a different compression driver as well. Nonetheless, I disagree with your unsupported statement, and I really don't see what leads you to that conclusion. What constitutes a "party speaker"? A 15" 2-way? Go tell Summa owners that their speakers are unpleasant party speakers, and see what kind of response you get.

[tinitus]

Originally posted by BHTX
15" 2-way? Go tell Summa owners that their speakers are unpleasant party speakers, and see what kind of response you get.

Summa appears to be a bit more intelligent design ... bigger waveguide with lower xo point
My point was that with a smaller mid like 8" you could get away with higher xo point ... and a smaller waveguide, but you are right, the diffraction device in 1086 is a problem, but I hope something could be done about it
Hell, are there only no-good waveguides out there
The Supravox waveguide could be interesting, but in the same price range as Gedlee/Summa

[BHTX]

Agreed. However, directivity is something I have yet to fool around with, and this project would hopefully change that. That said, I'm hoping to accomplish good directivity from around 1 KHz up. Since I can't do my own waveguides, the XT1464 seemed like a good compromise to toy around with. Maybe you're right though. I guess I won't know for sure until I try it. On another note, I'm not so sure how easy it'd be to get this particular waveguide, as it only appears for sale on websites overseas. I wonder where Lynn Olson got his.

I wasn't even aware of how to go about getting my hands on a Supravox product, much less the price of that horn. Thanks for the heads up.

[tinitus]

Some Supravox prices

http://www.audiokit.it/ITAENG/Altopa...x/SupraVox.htm

My status at the moment is a 3way with AE TD15S woofer, B&C 8PE21, CD tweeter either B&C DE500 or maybe Beyma CP380M, hard to decide

Woofers will be driven by Reckhorn 2 x A-401
8" mid will be run almost "loose", with very little xo components, time will show
Design makes a relative small waveguide possible, still looking fore one
When I get the time I will make my own elliptical
Sure, I may experiment with foamplugs or stuffing ala Gedllee

Its a tricky experiment with several possible flaws
One is the lower woofer SPL, but I only expect it to result in very tight yet deeper bass, one has to remember these are big woofers fore hifi

But I think a 2way with a 15" is even more tricky
Though Gedlee has shown the way, I dont see why others cant do the same
But if I were to do a 15" 2way I would look at AE TD15M

another one http://www.humblehomemadehifi.com/PAB-415.html

[-CGL-]

Tested XT1464 with BMS 4554.
Not nearly as nice as XT1086 and 4552.

[Saurav]

I'm no expert and this is an uncalibrated ECM8000 (and I was eyeballing the rotation angles), so take this with a grain of salt, but this is a BMS 4538 on an XT1086. The lower plot is of my midrange. The last curve is roughly at 45 degrees.



So... don't put too much stock in the actual response or the diffraction ripples, but you can compare the relative differences between the curves, since they all had the same mic setup. This should give you some idea of its pattern control. It does have a 'diffraction device', if I understand that right - the horizontal direction has a sharp change in flare.

[fivestring]

I have heard this is an excellent horn, but check this:
18sound compression driver

[tomcat9]

It has been over a year, has anyone had any more experience with the XT1464 horn? 18Sound says this horn is "constant coverage", is that the same as constant directivety?

Thanks.