Eminence Coaxial Towers

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Parts have arrived for the next project! I am VERY happy with the Markaudio Alpair 12.2 Pensils, but there are times when I want to put in some Zeppelin and just JAM! Unfortunately, the Alpairs don't do that well.

Enter the WLM DIVA/Zu Union clones. These utilize the Eminence Beta-10CX with some Selenium D220Ti drivers in a bass reflex tower (39Hx12Wx13D) tuned to 35Hz. They should be a great rock-n-roll point source speaker. Crossover is 2nd-order at 2500Hz with Audyn premium caps and Erse 14ga air-core inductors.

More pics forthcoming as I start building the cabinets tomorrow from my stock of 3/4" 11-ply Baltic Birch ply.

Parts for 2 sets ... a buddy bought the swag shown if I build him a set as well. Not sure how he will finish his, but I think I may paint mine with a Union Jack since they are my Zeppelin speakers. :D

Has anyone removed the screen from the D220Ti's? I am guessing it is there to prevent prodding fingers when mounted to a horn, but behind the dustcap, they should be safe. It is pretty thick wire, so I am concerned with dispersion.
 

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I have been thinking about an upgrade from the current full range + subs (2 way) to coax and subs (3 way) for a long time. I am particularly interested in polar response of the compression driver your using in the Eminence coax.

To eliminate the harshness you hear when you crank it you want to minimise the velocity of the driver producing upper midrange/trebbel. One way of doing is this is to make the driver very large (like a Gedlee speaker) or to use a separate driver for the lower bass, I would recommend going 3 way if the budget allows, however the coax should be a lot better than the full range due to the greater surface area.

The other driver that has interested me is the Beyma 8XC20:
http://profesional.beyma.com/ingles/pdf/8XC20.pdf
Although from the graphs the polar response is all over the place!
 
Has anyone removed the screen from the D220Ti's? I am guessing it is there to prevent prodding fingers when mounted to a horn, but behind the dustcap, they should be safe. It is pretty thick wire, so I am concerned with dispersion.

I removed screens from D2500Tis, I assume the 220 is mounted similarly. Removing it will leave a lip which you'll want to smooth out, you can just use any filler you want that'll stick in place. You may wish to get some reticulated foam, sold for aquarium filters, and make a little insert for the throat, as this helps SQ.

I also coated my phragms with a thinned combo of tacky glue (foam glue, but aleene's tacky glue would work here too) and talc. Lots of thin coatings, and this made for a much nicer top end.

Coating Phragms 1.jpg

Coating Phragms 3.jpg
 
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So funny story ... I kluged them together the other day to listen and the bass was unbearable! I was worried I'd have to do extensive mods to the cabinets to keep the resonance down.

Today I finished the crossovers (pic attached) and wired them back up. They sound GREAT! The bass was not at all overpowering and they were very neutral.

I can only assume that last time I had the woofer polarity reversed?

Anyway, long story short ... they sound GREAT! Next step is damping the cabinets and adding the terminals and L-pad.
 

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Oh yeah, I see it now. Really I was just prodding you to give more details about how you came up with the crossover ;).

Gotcha ... well I had designed one with the Excel spreadsheet and then I contacted Eminence. They forwarded my e-mail to a tech that built a "bookshelf" version of the 10" BETA 10CX with the Eminence ASD-1001. They hand tuned it on a spectrum analyzer for 2 weeks. He sent me the schematic and it is basically what they are selling as PXB2-2K5CX except that I left out the protection bulbs and am using an L-Pad instead of the fixed resistors.

Basically, it is a 2-way, 12dB/octave, 2500Hz crossover. I am not sure which slope they are using as the component values don't match what I get using the Excel sheet for any slope. BUT, when I plug their values in, I get a perfectly flat response!

I then took their values and using only air core, low DCR inductors and quality film caps ... Viola!

I listened for a few hours yesterday and am quite impressed with the sound. They are "loud" but not aggressive. The L-pad can be a bit touchy to get the level dialed in right, but once it is set, the imaging and balance was much better than I expected. I have heard people refer to the Tekton speakers as sounding "close to live" and I have to agree with that statement on the Eminence drivers. My MarkAudio's are the most neutral speaker I have ever heard but vocals are behind the drivers which makes it sound like they are beyond the front wall of my listening room whereas the Eminence put the vocalist right between the 2 drivers in the same room.

I use Norah Jones' - Come Away With Me - LP to detect aggressiveness and resonance and I am not detecting any with this setup. I don't know if it is just me, but does anyone else think that LP is not mastered properly? The CD sounds fine, but the LP can be VERY aggressive with the wrong speakers!
 
Craigtone,

How you connected Selenium driver with Eminence Beta? You probably needed some kind of adapter? And why you decided not to use some of Eminence HF compression drivers?

The BETA series Eminence drivers have a 1-3/8"x18 thread on the back, so no adapter required.

I chose the Selenium based on a recommendation from a friend that uses them to update drivers in the Classic Klipsch speakers. Being a big Klipsch fan myself, I took his advice. That and the response curve seemed a bit "flatter" both on and off axis than the selections Eminence had to offer.
 
craigtone,

I am not sure that using low loss inductors and caps will result in either better sound or lab specs. If Eminence tuned xover for standard quality components and you use, for instance, coils with lower DC resistence, you can easily get worse performance. It actually could spoil response curve (a little).
 
craigtone,

I am not sure that using low loss inductors and caps will result in either better sound or lab specs. If Eminence tuned xover for standard quality components and you use, for instance, coils with lower DC resistence, you can easily get worse performance. It actually could spoil response curve (a little).

FWIW, I did plug my DCR numbers into the spreadsheet and all appeared fine.
 
The CD sounds fine, but the LP can be VERY aggressive with the wrong speakers!

The CD sounds fine?! All hers, and most other CDs I've auditioned in the last decade are too forward/harsh, apparently being mixed more for the confines of a moving vehicle than a typical home room, so have to use 'smiley face' EQ to tonally balance them out in room.

Interesting that modern vinyl would be even worse unless it's for DJ apps where it has to 'cut through' the ambient noise, high damping of all those absorbent bodies.

GM
 
The CD sounds fine?!

LOL ... Let me re-phrase ... "The CD sounded less harsh than the LP"

For me, it is the upper midrange that makes a sound that makes me cringe akin to scratching nails on a chalkboard. With my old Klipsch RF-7's, the LP was un-listenable until I did the DeanG crossover mods and damped the plastic horns ... then it was "bearable" with just the occasional wince.
 
Craigtone,

I´m also planing to build a speaker with the Eminence Beta 10CX. First I wanted to use the APT 50 driver after reading quite a lot of positive comments on a german build project (CT235 from Klang&Ton). But looking at the specs I´m not sure. The ASD 1001looks a lot better and the Selenium you used even more so.

You said you got a flat response with the original Eminence values for the crossover. Was this calculated or measured?

William
 
wuffwaff,

I have all parts ready to build CT235 and I think that with Beta 10CX, APT50 is optimal. You shall have better integration and better HF extension with APT50 than with other compression drivers. If you decide to use bigger cone like Beta 12CX than, probably, you could consider bigger diaphragm drivers. Also I think that the charm of phenolic drivers sound like APT50 is unsurpassed. You should not go to disproportionally big HF drivers with Beta 10CX unless you intend to misuse loudspeakers a lot.

I think that you should stick with Klang and Ton project because you have completely predictable results (measurements, etc). My room is not too big and CT235 bass loading is particularly well suited for smaller rooms (not too much low end).
 
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