# 3.75 cu.ft. sealed sdx15 w/ oaudio 500w plate amp



## RodK

Well I finally got all my pieces and started building this week. I had a stroke of luck at a local specialty lumber store near me and found 3/4" mdf with fir veneer on one side and cherry veneer on the other. I am using the cherry side for my box. It was just over 4 cu.ft. to start , but with the driver and bracing it is about 3 3/4 cu.ft. now. the 1/4 round is maple. here are a few pics to start.


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## RodK

I want to stuff the box to make up for lost space. Is it safe to use loose polyfill with the plate amp, or am I better off using pillows with polyfill?


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## Mike P.

Nice box. Pillows would be easier since the plate amp is an open back design.


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## RodK

Thanks Mike. Couldn't have done it without your help. Hopefully I can finish staining and varnishing this weekend and get this sucker assembled. hopefully have some more pics soon.


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## RodK

stain and 3 coats of varnish just finished. more pics to come tomorrow.


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## RodK

here's a few pics to show what I am replacing.


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## ironglen

Looks like early Halloween...sweet!


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## RodK

I used polyfill pillows to stuff the box. One pillow is close to the plate amp. Is that going to be an issue , or should it be ok. I left the pillows loose in the box, should I staple them down?


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## StereoClarity

I wouldnt worry to much about affixing the stuffing. The plate amp has it's heat sink on the outside so most of it's heat will travel that way. 

I ran one of those plate amps powering a shiva-x and a pair of Peerless xxls 12's (not at the same time) and it never really got that hot. 

I do recall that amp having some built in low end boost. Try and remember that when tuning. It would be smart to look into it. If I remembered how much and at what frequency I'd tell you bit I honestly can't remember. I think it is really low around 20hz or something.


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## RodK

I won't get a chance to play around with tuning until the weekend. It has selectable boost at 12, 16, 20 and 25 hz. Modelling in winisd shows going over xmax at the 16 hz setting but it won't hit xmech. I have it at 20 hz right now.


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## tcarcio

Looks great. I think you will be very happy with it. :T


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## RodK

Here's some pics of it all finished. I am into this for under $500 total and this is my first build. So far so good.


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## dboff01

RodK said:


> Here's some pics of it all finished. I am into this for under $500 total and this is my first build. So far so good.


Beautiful cabinet. Surely some great work for a 1st build.

Any details on the stain/sealant used to finish the box?


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## Jstslamd

What kind of wood did you use ?


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## RodK

the wood is 3/4" mdf with cherry veneer on one side and douglas fir on the other ( I used the cherry side). The 1/4 round is maple. The stain is Minwax Gunstock. I used Minwax semi gloss varathane.


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## dboff01

RodK said:


> the wood is 3/4" mdf with cherry veneer on one side and douglas fir on the other ( I used the cherry side). The 1/4 round is maple. The stain is Minwax Gunstock. I used Minwax semi gloss varathane.


Did you use edge band veneer for the end cuts or is that exposed MDF?


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## RodK

I used veneer on the top, but just left the back and bottom edges raw mdf.


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## Binary

Looks great!

How's it sound?

I love the SDX 15 driver.


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## RodK

I had some problems with the Oaudio plate amp and had to send it back yesterday. But from what I did hear, it sounded very good. Much more musical than my last sub.


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## Mike P.

Just curious, what was the issue with the amp?


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## RodK

It would just stop putting out sound , but the light would stay green. If I turned the main power switch off and back on it would work for a bit and then stop again. As per Eric at Oaudio, I tried upping the sub volume in my receiver and also pulled the amp out and checked all the circuit board connections. Everything checked ok, so I sent the amp back to them yesterday.


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## Binary

LOL> The SDX beat the amp up so bad it failed.


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## RodK

I wish I at least had a chance to crank it........lol!!


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## Binary

Didn't i warn you that this thing will wake the dead and make basement dwelling mother-in-laws heads explode?

LOL.

It looks great, i just really really can't wait to see your reaction to the gobs of output that this driver is capable of.


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## RodK

thanks, I'm looking foreward to it myself

It hurts to put in all that work and then have a problem.
I hope I get the new amp soon.


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## Binary

Im just sticking my finger in the wound here... but if you went with a pro-sound amp, you wouldnt be without a subwoofer right now...:whistling:


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## RodK

Thanks:boxer:


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## RodK

Finally got the new amp today and so far so good. I will set it up properly on the weekend. Hope to get some measurements soon as I am on holidays next week.


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## nc535

Binary said:


> Im just sticking my finger in the wound here... but if you went with a pro-sound amp, you wouldnt be without a subwoofer right now...:whistling:


What prosound amp would you go with for SDX10s, which max 250W RMS sealed? I picked up a Crown xti 2000 for its built in DSP, which is great, but it apparently has weakness below 20 hz. I reasoned that wouldn't matter because I only needed half of its max power. But the DSP won't do any filtering below 20 hz. So maybe a non-DSP AMP plus MiniDSP would have been better.

JackNC


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## RodK

Well it's been a few days and the sub is pounding along nicely ( I guess the first amp was definitely a dud). I couldn't seem to get rew working properly and will have to do some more reading to find out what I was doing wrong. If I can figure it out , I will post my measurements here. The sub is especially great for music.


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## robbo266317

I'm glad your enjoying it. I still get a smile everytime I hear nice clean bass in music and think "that wouldn't be there without the sub
If you post your setup and problem in the REW forum they will be able to sort it out.

Cheers,
Bill.


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## RodK

Thanks, Bill. It is quite "ear" opening to hear songs all over again and what I have been missing.

I have already left a post in the rew thread, hope to get help soon.


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## Binary

The crown XTI series are not known for having very good output in the bottom most octave, that is just a design weakness of that series. I'd recommend a Behringer EP2000, or the newer iNuke series if you want to try something with DSP built in. Personally, i use a DCX 2496 for my DSP, and a QSX RMX2450 For the SDX15 in a 14~ cube internal LLT tuned for 15hz.

http://www.behringer.com/EN/Products/NU1000DSP.aspx

The iNuke1000DSP fits what you're looking for.

Remember, you can always turn the gains down to limit the output. But you can't EASILY make a weak amp stronger.


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## nc535

I would buy that in a minute if I didn't already have the Crown, which by the way seems to have all the power it needs to drive my subs, which only need about 1/3 of its maximum rated output


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## Ejorne

Is this oaudio 500W plate-amp enough for the SDX15?

I have also a sdx15 fed by a Hypex DS4.0 plate-amp. This amp rated at 400W rms. 
(see this topic at a dutch forum... Oh, i cannot make a link? )
Anyway, It goes as louder than i can handle but i hope with more power (for example the Hypex DS8.0) to get more controll en detail. Is it so?

I have looked at those Behringer amps. With build-in dsp it looks to me a great amp. BUT, the power from those Behringer amps is rated at max-power. So, the 1000DSP will give 1000 watt at 4 Ohm bridged at maximum. So, maybe this Behringer iNuke 1000DSP is weaker than mine Hypex DS4.0? Which means i probbably better go for the iNuke 3000 or 6000?

And what about de damping factor? Is 140 high enough? Mine hypex DS4.0 has a factor of 1000. I'm looking for more detail in bass and someone did tell me that this damping factor is important and must be as high as possible...

So, should i stick by mine Hypex DS4.0, go for the DS8.0 or pick a Behringer 3(6)000DSP?

/edit;
Btw, i did test with placement around my room. First my sdx was placed as downfire but now it has become front fire. Much better now with ff and righg place. But want those last improvements too if possible


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## RodK

I haven't been around here too much lately, but wanted you all to know that I am still thrilled with this sub. It has been the best addition to my system and still puts a smile on my face. Thanks to all that helped along the way. :bigsmile:


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## Mike P.

Good to hear you are enjoying your sub. We're still waiting to see if there will be a SDX15 MK II.


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## RodK

I know. I was SO lucky to find a good used sdx15. I can't believe the bad luck Bob and CSS are having with that driver. I couldn't have waited this long.


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## RodK

I haven't been around here much lately. Too busy enjoying my clean tight bass!!! I truly feel sorry for those that were waiting for the sdx15mkII. This sub build was the best upgrade to my system. Thanks again to all that helped along the way. 

On a side note, also sorry to see that oaudio is no longer out there. I feel so lucky to have gotten what I got when I got it.


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## steve nn

I feel fortunate to have mine also. It’s a great driver imo and sims really well for a 15”


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## RodK

It has been forever but I am back here. 

So sorry to see that the Mark II will never happen. 

The sub is still making me smile, and now with no Mark II coming and Oaudio no longer around, I feel so lucky to have gotten what I did when I did.

Mike, nice to see that you are still as helpful as ever. I could not have done all this without your valuable help. Keep it up.

Long live DIY!!


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