# Help with SDX-15 Build



## jaysant1 (Feb 1, 2010)

Hi Guys. I know there are a thousand SDX-15 builds posted on here. I have probably read just about all of them. But now I'm building my own subs and need some guidance. I already have 6 SDX-15 sub sitting in my garage for a year that were supposed to be used for a project that never came to fruition. I'm really looking for guidance from some of the guys who have used this driver in the past. What I would like is to build a ported enclosure most likely with a slot port. I would like to sub to be extremely fast, accurate and tight. I would also like it to play low as possible without sacrificing the quality. If someone would be kind enough to give me an idea about size and tuning point for the sub to accomplish what I am trying to do I would be most appreciative. I have really no space requirements or limitations. I'm not trying to use all 6 Subs either probably 2 per enclosure at most. Thanks in advance for any input.


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## Mike P. (Apr 6, 2007)

Is this for HT? How big is the room? Is the room closed off or open to other areas?


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## jaysant1 (Feb 1, 2010)

Music and Movies 50/50. Room is 25 x 35 x 8 totally enclosed (dedicated theater / listening room)


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## jaysant1 (Feb 1, 2010)

PS Mike P. any experience with Velodyne plate amps with built in eq from their DD series subs? I have a couple of them lying around. Was thinking about using them. Thoughts?


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## Mike P. (Apr 6, 2007)

It will depend on how much power the amp produces and at what frequency the Hi-Pass filter is set at.


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## jaysant1 (Feb 1, 2010)

Supposedly they are rated at 1250 rms 3000 peak. Hi pass filter is variable via on screen menu. Any design ideas based on the info of the room and requirements you had asked for?


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## Mike P. (Apr 6, 2007)

The modeling below is a single sub in 10.cu.ft. tuned to 18 hz with a 1250 watts input and a Hi Pass filter set at 16 hz. A slot port 4" high x 12" wide and 34" long would keep the port air speed under 23 m/s. A pair of these would be impressive.

What is the model number of the plate amps you have? I've never heard of a plate amp with an on screen menu.


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## jaysant1 (Feb 1, 2010)

I don't know the model # of the actual amplifier. They were supposed to be replacementsfor a couple of velodyne DD-15 which fell victim to an electrical storm. They have composite outs for their on screen setup menu. They supply you with a fairly high quality microphone that also gets commected to the back of the unit. In your onscreen menu you can eq the room for the subs I think you get 6 or 10 points that can be moves across the frequency spectrum and adjusted up and down. These amps are not for sale seperately only for service (I'm a veoldyne dealer). I assume the 10 cu ft excludes the volume of the port? Thanks for all the help I was actually hoping you would chime in fromt he beginning you seem to really help a lot of the guys on the forum.


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## Mike P. (Apr 6, 2007)

I just looked up the specs on the amps and you are one lucky guy to have them. With the adjustable Hi-Pass frequency and slope you can easily get the most out your subs. Being a Veoldyne dealer definitely has its benefits!

The 10 cu.ft. is the net volume, to that you add the displacement of the sub, port and bracing to get the total internal volume needed.


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## jaysant1 (Feb 1, 2010)

I guess so! Thanks again for all the help I know your really one of the guys on the forum who knows his stuff. Thanks for taking the time to share with the rest of us. PS if you want one of those amp I willsee if I can finagle one out of them for you. I'm not sure what they cost but I know they are not as much as one would think.


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## Mike P. (Apr 6, 2007)

Thanks for the compliments and the offer. I'm hoping you will start a build thread with pics when you get started on your subs.


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## Binary (Nov 23, 2009)

I'd be interested in one of those amps!

Im using an SDX-15 in a 24x24x42 box Slot port. Nets roughly 16 cubes, add light stuffing to that, (10% apparent increase in volume) and im gettin roughly 18 cubes. tuned for 15~16 hz its pretty intense. If you do two of them you've got more sub than your theater should need. 4 would be absolutely NUTS!

the DD amp is a perfect match (almost) for the SDX. its got a little extra juice which is a good thing. The best part is the EQ built into those amps. Its basically an SMS-1 inside of your plate amp.


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## jaysant1 (Feb 1, 2010)

Lots of people are interested in these amps apparently. Unfortunately I can only replace as many as I have sold that are out of warranty. I have two that am personally using which means getting any more will be tough. Your right about the built in eq. It's a very powerfull room tuning utility. Even the Mic they supply with the unit is very high quality compared to the stuff that comes with a lot of other devices.


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## jaysant1 (Feb 1, 2010)

Mike P. WOuld the dimensions 5.125x27x12 give me the same tuning frequency as the 12 x 4 x 34 dimensions that you had given me? Just about the same volume.


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## Mike P. (Apr 6, 2007)

No, that won't work. Tuning is about the port surface area and length. Let me know what your cabinet internal width is and I'll figure out what you need for a 18 hz tuning frequency.


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## jaysant1 (Feb 1, 2010)

27 wide 17 deep height variable to compensate for port size.


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## Mike P. (Apr 6, 2007)

2" high x 27" wide x 38.75 long will tune the box to 18 hz.


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## jaysant1 (Feb 1, 2010)

Great thanks.


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