15" PA Subwoofer build

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15" PA Subwoofer build

Post by mattsk8 » Thu Apr 23, 2015 1:43 pm

I originally built the mains for our church a couple years ago, that thread is here. http://www.diyspeakerforum.com/viewtopic.php?f=2&t=26

I knew the mains would need a sub (or subs), and finally got around to building them. Working with Jerry McNutt (engineer at Eminence and all around great guy) we designed these. The cabinets are called "ABC boxes", and work similar to a bandpass box. Basically there's the main chamber where the woofer is mounted that is 2/3 of the cabinet, then there's a port connecting the main chamber to a side chamber (the other 1/3 of the cabinet), then the main and side chambers are front ported (all 3 ports are the same size).

The subwoofer used is the Eminence Definimax 4015ULF, which is a new driver offered by Eminence. http://www.eminence.com/speakers/speake ... _4015ULF_8

Test fitting the brace and the divider panel.

Front baffle is 1.25" thick.

Cut and boxed in handles to carry them, these suckers are heavy.

Test fit.

Glued up. I liked the looks of the triangle ports, so I did the conversion from round to triangle. Then to get the recessed front baffle look, the easiest way to pull that off was to simply glue the wood to front of the cabinet. The port depth was considered prior to doing this :D .

A good friend of mine owns a truck accessories shop, and he sprayed these for me with spray on bed liner. While a tad rougher than I would prefer, it's a great trade off because this finish is basically indestructible, I could've probably drug these to church behind my car and they wouldn't get scratched :lol: .

Made some grills as well.

And a picture of the sanctuary. Arrows pointing to the mains, and the subs except one of the subs you can't see because it's under the piano.

Going into this I was very nervous about filling this sanctuary with great sound, its a huge room and an acoustical disaster. In the end, I'm very happy with the way this system turned out, it's extremely LOUD, and these subs are more than enough to fill the room with plenty of thunder. I can turn this up as loud as anyone would ever want to listen to it (with plenty of room for more beyond that 8-) ), and we aren't close to it's limits. The amps we're using are one Crown XLS 2500 driving both mains; and 2 Crown XTI 1002 amps, one on each sub. In hind site, I would probably have gone bigger on the subwoofer amps, but these do a nice job. We also have a DBX Driverack PA+ to manage all of it.

In addition to all you guys on the forums and the boys at Meniscus for answering questions and helping me layout this sanctuary build over the years, I really need to thank Jerry McNutt at Eminence for your help designing this box, as well as answering all my questions through the process. Really glad I got to know you through this, and I'm looking forward to working with you on future builds as well!! Thank you!

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Re: 15" PA Subwoofer build

Post by stentorvox » Thu Jul 09, 2015 12:38 am

These look great, sturdy and well-designed.

What kind of instruments do you pop thru these?
Do you play recorded or MIDI accompaniment trax thru these as well?

I am working with some 15" Eminences into specifically designed speaker cabs with four-inch tube pipes (12 of them) mounted above each speaker (as Helmholtz resonators), to reproduce MIDI keyboards, but it will be awhile before I listen to the final outcome. You are an encouragement!


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