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Recently I updated my theater to a Dolby Atmos System. Adding this really made a huge difference in my system. For example, watching the opening scene of Ford vs. Ferrari will never be the same. The cars and announcers come overhead, sounds like you are right at the race.

But since I created my high efficiency Klipsch THX clones, normal in-celling speakers, just weren't going to to cut it anymore. Enter in the Eminence Beta 10cx. A 10" driver that allows you to add any TPI compression driver to turn it into a coaxial. Very similar to the driver used in the Volt 10's. But since the Volt 10's have been out of stock since...wel a while now, I thought I would design some myself.

I already had a few JBL D220ti's and Eminence sent me some F110m-4 drivers. So I decided to give them both a try. in the Atmos build.



Box Design


The box is a simple 14x14x7 box using 3/4" material. With the woofer cutout directly in the center. The coaxial driver just screws on to the back. One thing to keep in mind is where to put the terminal cup. If you plan to put it on the back, try offsetting it. I offset mine toward the bottom. If you do not do this, the compression driver could get in the way of the terminal cup.


Parts Used


10" woofer: "Eminence Beta-10CX 10" Coaxial Driver" from www.parts-express.com!


JBL Compression Tweeter: "Selenium D220Ti 1" Titanium Horn Driver 8 Ohm 1-3/8"-18" from www.parts-express.com! or


Eminence Compression Tweeter: "Eminence F110M-8 1" Mylar Compression Horn Driver 8 Ohm 1-3/8"-18 TPI" from www.parts-express.com!


Circle Terminal Cup: "Square Speaker Terminal Cup 4" Gold Binding Post Banana Jack" from www.parts-express.com!


Crossover Design


Both crossovers are fairly similar. The use a second order on the woofer and compression driver. The compression driver also has a notch filter to even out the on axis response. Also keep in mind that the tweeter does have reverse polarity.


Eminence


Eminence Final SImulated Response




JBL


JBL Final SImulated Response2

Results


Eminence


The Eminence is voiced more toward a natural roll-off. This gives it a nice easy to listen to speaker, but can lack some of the high frequencies that some really enjoy. However, this also makes the speaker easier to listen to for longer periods of time. I have found this especially enjoyable for home theater and listening to Jazz.


Eminence Final SImulated Response2

JBL


The JBL is voiced more toward a flat response. This gives it higher highs, but can also be a little less forgiving when listening to it. However, it does really well during music. So if you tend to listen to more music then movies, this might be the one you want to go with.


JBL Final SImulated Response2

Cut List


This box should be made from 3/4" material. You can cut these any way you want, but here is one way you could cut the pieces. If you do not have a table saw, your local big box store should be able to cut these for you.


Capture

1. (2) 14x14 pieces


2. (2) 14x5.5


3. (2) 12.5 x 5.5
 

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Good Job, Al!

Took a sniff at the "JBL" Selenium D220Ti and noted the specs changed over the years (I've use them to upgrade some PA speakers about 8 years ago) Very interesting, the are rated down to 1,000 Hz now and manufacturer ratd down to 1,500 Hz...sweet!

Soooo, I checked out your video and noted that the Emience drivers was crossed over at 2 KHz--wondered what the JBL was doing so compared the filters and I guess that the D220Ti was crossed over at 2 KHz also. Hmmmm, to me it would make sense to attempt to drive it down lower at 1.5 KHz to prevent beaming of the 10 incher. If it can do it, it is rated to do it and would suppress the breakup at 2.8KHz of the CX10---AND help with beaming I was thinking crossing that compression driver at 1.5KHz might be a good idea.

Just wonering if you tested the JBL/Selenium driver at 1.5KHz or did you match it to the Eminence XO point? If you did give it a shot at 1,500 Hz---were there any major issues with it so you pushd it to 2,000 Hz to avoid issues? Do you have any plans to screw around with the XO with that JBL driver and see what it will do? Maybe I''m nuts but it seems that the JBL/Selenium specs have changed over the years so I ponder if it can go lower without issues is all...any plans?

Thanks again for the information---that wee Emi might be perfect for the CX8...Christmas is cancelled except for me! ;)
 

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Discussion Starter #6
Good Job, Al!

Took a sniff at the "JBL" Selenium D220Ti and noted the specs changed over the years (I've use them to upgrade some PA speakers about 8 years ago) Very interesting, the are rated down to 1,000 Hz now and manufacturer ratd down to 1,500 Hz...sweet!

Soooo, I checked out your video and noted that the Emience drivers was crossed over at 2 KHz--wondered what the JBL was doing so compared the filters and I guess that the D220Ti was crossed over at 2 KHz also. Hmmmm, to me it would make sense to attempt to drive it down lower at 1.5 KHz to prevent beaming of the 10 incher. If it can do it, it is rated to do it and would suppress the breakup at 2.8KHz of the CX10---AND help with beaming I was thinking crossing that compression driver at 1.5KHz might be a good idea.

Just wonering if you tested the JBL/Selenium driver at 1.5KHz or did you match it to the Eminence XO point? If you did give it a shot at 1,500 Hz---were there any major issues with it so you pushd it to 2,000 Hz to avoid issues? Do you have any plans to screw around with the XO with that JBL driver and see what it will do? Maybe I''m nuts but it seems that the JBL/Selenium specs have changed over the years so I ponder if it can go lower without issues is all...any plans?

Thanks again for the information---that wee Emi might be perfect for the CX8...Christmas is cancelled except for me! ;)
When I get home later tonight I'll post the crossover slopes for you. And give you some more thoughts on what I did and why.
 

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Discussion Starter #7
Good Job, Al!

Took a sniff at the "JBL" Selenium D220Ti and noted the specs changed over the years (I've use them to upgrade some PA speakers about 8 years ago) Very interesting, the are rated down to 1,000 Hz now and manufacturer ratd down to 1,500 Hz...sweet!

Soooo, I checked out your video and noted that the Emience drivers was crossed over at 2 KHz--wondered what the JBL was doing so compared the filters and I guess that the D220Ti was crossed over at 2 KHz also. Hmmmm, to me it would make sense to attempt to drive it down lower at 1.5 KHz to prevent beaming of the 10 incher. If it can do it, it is rated to do it and would suppress the breakup at 2.8KHz of the CX10---AND help with beaming I was thinking crossing that compression driver at 1.5KHz might be a good idea.

Just wonering if you tested the JBL/Selenium driver at 1.5KHz or did you match it to the Eminence XO point? If you did give it a shot at 1,500 Hz---were there any major issues with it so you pushd it to 2,000 Hz to avoid issues? Do you have any plans to screw around with the XO with that JBL driver and see what it will do? Maybe I''m nuts but it seems that the JBL/Selenium specs have changed over the years so I ponder if it can go lower without issues is all...any plans?

Thanks again for the information---that wee Emi might be perfect for the CX8...Christmas is cancelled except for me! ;)
Typically I would want to crossover closer to 1500hz with a 10 inch woofer and the JBL can handle a crossover in that region. The issue comes more from the Beta 10CX. Even if a compression driver can crossover low, the waveguide itself also helps determine the crossover point. Some waveguides are very generous and allow you to crossover as low as 500hz (assuming your compression driver can handle that). While others...not so much. I don't have any good pictures of it, but if you look inside the acoustically transparent dust cap of the Beta 10cx, you will see a very small 60 degree conical waveguide. Which really hinders how low you can crossover a compression driver. In this case, it really naturally allowed both drivers to crossover close to the same place (around 1880hz). It might have been possible to work on it some more to get it closer to 1500hz (I'm not sure it is in this waveguide), but it would have taken more components or added distortion. And with such a small cabinet you also want to keep the crossover as simple as possible. At least that was my thinking about it. Interestingly enough it crossed over a little lower than the Volt 10 (2Khz), but not by much. It would be my assumption that was the same issues they were dealing with as well.

Now for the really cool fun graph 🤣

3065070
 

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This is awesome, yes I agree I too have been waiting for the Volt10 to come in stock as well. This seems like a decent alternative.
 

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Would you also recommend this in-ceiling for atmos or does it need a box and baffle? This could be my solution for the other 14 speakers I need in my theater.
 

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I am interested in doing this with eminence parts.

I dont understand the parts need for the cross over

Can someone put together a parts list
 

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I want to build one with the eminence for in ceiling atoms and surrounds in wall. can you help me with the xover and what parts I need for it.. Thanks
 

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