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Discussion Starter #1
Hey ppls, a while ago i came here in search of answers to which i did find a few (thanks to those ppl who offered help). That said after further research and lots of simulated modeling, i was ready to begin.

My project a Vented 283L subwoofer for HT use.
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DRIVER - Exodus Audio Tempest-X (15" driver)
AMP - Oaudio 500W plate amp
PORT - 155mm ID with custom made 50mm flare both ends
ENCLOSURE - 25mm MDF throughout, outer dimensions 1050x550x675mm.

1 - Puts my car subs to shame. No frills, but it does look well constructed.
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2 - Amps naughty bits. Was much smaller than I expected, and not very heavy BUT it has more power than I need, runs very cool, lots of tweaking available, and uses BASH Technology** - and its cheap!
** BASH® is a patented High Efficiency Power Amplifier circuit topology that has taken the best of Class D and Class AB and created a new class of its own.
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3 - Making a coffee table. Decided on screw over clamping method. Worked great!
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4 - Thats alot of routing. The flare was probably the most time consuming aspect of the whole job.
design - I used sketchup to fully model that construction process to ensure what was in my head actually worked!
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5 - Test fitting the driver. Router bit wasn't able to penetrate all the way through the front baffle (50mm). So the last bit was tackled with a jigsaw. Was a little rough on the inside so a used a 1/2" round over bit to neaten up (not seen in this photo).
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6 - Both flares test fitting onto pvc pipe. Cheers to 'Collo's DIY Subwoofer Enclosure' website for guidance on constructing this.
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7 -
Test fitting the amp, rebate depth was spot on.
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8 -
Lots & lots of builders filler. This stuff worked great, and set very fast! Dont mix to much at once as its working time is pretty short. Used this to mold both flares and as a general filler. Nice and easy to sand.
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9 - Wasnt sure if there was enough bracing, but once it was in i knew that it was fine. Box is solid as a rock.
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10 -
I used a PVA glue wash to seal the flare inside. Decided to do this to help reinforce the filler since it wasnt going to get a coat of paint.
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11 - Loading all the polyester fill. Box is designed for heavy(100%) fill, as per the instructions in the application guide available for the sub. Im not sure if I have enough in there to be honest (can someone advise if i need to add more). I used a product by Quitestuff, an R1.5 insulation batt with acoustic deadening properties. Just got it from bunnings.
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12 -
Day 1, 4 coats of auto based primer/filler, then lots of sanding. Day 2, 4 coats of satin black on the port/flare and feet. Day 3, 2 coats of tinted Hammered Metal finish (gunmetal+black tint). Day 4, drying. Day 5, another 2 coats of the hammered metal finish then 3 days drying.
*also you may notice the LED bezel mounted just above the port.
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ALL DONE!!


13,14 - Driver installed using 1-1/4 bolts.
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15 -
Now you all can appreciate the size of this monster. Way too heavy for even 2 ppl to lift. I use a trolley to move it around. btw this isnt the theatre, just its testing ground.
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16 - Im pretty pleased with the end result!
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Spent a number of weeks constructing this. Firing it up for the 1st time, my very first thought was, oh , i hope this doesn't crack the ceiling. Having little chances to audition decent dedicated subs I dont have much to compare by. I have heard the S350 by LSK and own logitech Z680 speakers (which sound pretty awful). My new sub is nothing like anything I have heard before. It goes far deeper than I expected, but still has some musical quality about it. Its hard to describe but different sources do sound different, unlike the logitech's where all the bass sounds the same (except for the peaks).
Anyways its still early days, and its not calibrated or plugged into a
AVR.

Act 2 is to build some floor standing speakers and a center channel.
Then get myself a projector, in ceiling rear speakers, AVR and im set for some serious movie/game time.


3 weeks later

Ive had a chance to start to get to know this sub. Its still not calibrated or plugged into an avr, and currently is plugged into the front channel with its crossover enabled. Im still a little worried about the amount of dampening. I think i might need to add some more to create more resistance, as occasionally at high volume I think the driver might be exerting to far. All the modelling indicated that it would be within a safe amount (xmax) but im not sure if this is actually happening in real world. Otherwise everything is sounding great at this point!
 

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Discussion Starter #6
Designed it with Unibox and Bassbox6.
Vb = 283L tuned at 17.7-18hz with a simulated F3 of around ~18Hz

the subsonic filter is currently set on 16Hz, but i have had it set on 20Hz previously. My understanding is, for it to achieve the simulated F3 i would need to leave the subsonic filter set to 16Hz otherwise its going to drop off to soon?
 

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The O-Audio amp applies boost at 3 of the 4 selectable subsonic frequencies. Since the company refuses to give out any information and their published graph is hard to read, the best estimated guess of what the amp is doing is no boost at 25 hz, 4 db of boost at 20 hz, 6 db of boost at 16 hz and 8 db of boost at 12 hz. Another issue is what order of filters are used, 2nd, 3rd, or 4th.

Your design of a Tempest-X in 283 liters tuned to 18 hz would benefit from a 6 db boost at 16 hz along with a 4th order subsonic filter according to my modeling. A problem arises with over excursion if the filter is only 2nd order. Without any help from O-Audio it's not possible to narrow down the problem any further. Whether you're experiencing an over excursion problem or the amp is clipping from the 6 db of boost, the solution is to turn it down a bit to alleviate the problem.
 

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Very nice looking sub, wonderful finish work! I noticed that you have built car subs, but is this your first HT sub?.. it's my understanding that it is?
 

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Discussion Starter #9 (Edited)
This is my 1st sub, HT or otherwise, I havnt done anything like this before. Really enjoyed the process from design through to completion. Was a good project, and now im about to start work on some floor standing speakers and center (www.customanalogue.com/elsinore/elsinore_index.htm). Designing good mains was a little beyond my knowledge so i thought it was best to utilise someone elses design.
 

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Wow, very impressive build for your first subwoofer! The port is a work of art and I love the front panel led. The finish is excellent. Your net box volume is extremely close to my own Tempest-X cabinet. Do you have any idea how much yours weighs?
 

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That is a very nice looking sub, the finish is really good.

Just one question, being in Australia where did you get the amplifier and why not an Behringer EP amplifier?
 

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Discussion Starter #14
not sure what the weight of the sub is aaron, all i know is i cant lift, even with someone to help is very difficult to move, sooo ive resorted to using a trolley to get it around.

I was originally going to purchase the amp directly from oaudio and import it however i ended up not needing to as the guys that i purchased the sub from Audiomarketplace.com.au, ended up getting these in stock. To top off they appear to have ordered a customized unit as i noticed this comment on there website.. 'The one imported from us (direct from oaudio) has a peak frequency response before the subsonic cut off which was not documented in the specification. This one that Stuart ordered from the manufacturer has been modified to give a flat response up to the cut off frequency selectable with the low frequency extension knot.'

Main reason i went with this plate amp was;
a) i didnt like the cheap jaycar etc plate amps,
b) it appeared to be a quality built amp with plenty of power and some nice features.
c) i didnt really want to use an external amp, as i personally prefer a single unit.
d) it didnt really cost all that much!, around half the cost of a Behringer (i bought it before the ozzy dollar dropped)
 

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Sorry to bump up an old thread, but I love this build. At one point, my build was going to be for a Tempest until I found out they would be out of stock for a long time.I love the paint on this enclosure. You said it was "tinted Hammered Metal finish (gunmetal+black tint)" Who makes this paint? I've been to HD and Lowes and they have the Rustoleum Hammered series, but nothing that looks like this.
 

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Stuck Pixel said:
Sorry to bump up an old thread, but I love this build. At one point, my build was going to be for a Tempest until I found out they would be out of stock for a long time.I love the paint on this enclosure. You said it was "tinted Hammered Metal finish (gunmetal+black tint)" Who makes this paint? I've been to HD and Lowes and they have the Rustoleum Hammered series, but nothing that looks like this.
If I had to guess I think he sprayed the hammered finish with a gun and probably reduced it to get it to lay in a finer texture. But I also may be completely wrong and just gonna be sticking my foot in my mouth.
 

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Discussion Starter #17
Wow, never thought I would be adding more to this post!

Jstslamd is correct. It was thinned down (i think by around 15%) and then sprayed. Paint brand was Galmat. I bought a 1 litre tin. I asked the guys at shop if they could add black tint to it, since I wanted a dark finish. They added only a very small amount since they didn't want it to negatively effect the paint to much.

From memory the first coats ended up with a very course finish (actually looked pretty good). The final coats seemed to sink into the texture and kinda smoothed out the finish. At first I was a little disappointed a but I think now it was for the better.

Updating you all, my theatre room is now complete (has been for about a yr and a half). I have a Pioneer LX72 (or SC-25) and although this amp doesn't provide all that much in bass control (eq) the sound is incredibly flat/neutral. Im also very happy with how well this sub merges with my main/surrounds. When required it can really provide it all (and more), but for the most part it tends to just sit in the corner rumbling very quietly to itself.

I should mention that with movies and music I am rarely drawn to the fact that I even have a sub. It basically aids in completing the soundfield, generating that full dynamic sound that can only be had by this kind of hardware.

I should note that my mains are big. They can easily hit 50-60hz, though the xover is set higher. I do think this helps with the overall balance between mains and sub. I should also note that I think a large room would allow for much better results. My room is on the small side and while im content, I do sometimes wonder how much better it would sound if it had more space to output soundwaves into!
 
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