First build here. Goal, like many of you here, was to create a subwoofer that would do well with movies (down to 20hz) and music (50/50), yet not take up a large footprint. Budget was ~$500. With the space I had available, maximum box dimensions gave me about 130L to work with. This left me with two typical options for a box this size, a sealed 15" or a ported 12". Decided to go with the ported 12".
Ended up using the Shiva-X driver along with the Rythmik A350 basic plate amp, rated at 380W rms. The Shiva-X could probably take another 150 watts or so without bottoming, but the Rythmik at $159 compared with the next step up like the Dayton HPSA500 500W for $240 I couldn't justify the extra price for a 1-2db gain. Plus it has a 9-way highpass filter, which is nice.
Main factors for going with the Shiva-X is the advertised low distortion and high excursion. The driver is new to the market, so there isn't much to go on out there. Kevin Haskings was helpful in helping me narrow a design as well. Between the help of Kevin and using WinISD I had the following response curve, using the full length Parts Express flared 4" port. This is Kevin's response curve, WinISD yielded similar results.
Next I ironed out the max footprint I wanted, which is 16"W x 21"L. To get the volume, it needed to be 32" tall. This gave a box approx. 130L including bracing, then taking out another 5L for the volume of the driver and port gave me a final volume of 125L (plus or minus a few L). Also, since I wanted the subwoofer as close to the wall as possible, this eliminated a rear firing port. So I could go with front, top, or bottom. I didn't want front since I didn't want to look at the port, didn't want top since people could drop things down there, so that left a bottom firing port. That meant I had to make a pedestal to give the port sufficient clearance, so I had to also construct a 4" tall pedestal.
With the help of my buddy who had all the woodworking tools, we got to work . Used standard 3/4" mdf from Home Depot. Below are a few pics of the bracing:
Front panel is 2 sheets of 3/4" mdf, pedestal is also 2 layers of mdf stacked. Final assembly pic below, sealed with 3 coats of wood sealer. You can see the pedestal feet and pedestal in front of the box.
Ugh, next comes the painting. I had a hard time with this since I don't have any kind of painting equipment. My first ambition was a piano black finish, but I quickly dismissed that after seeing the work and tools involved! Decided to go with a satin black finish since there would be no issues with reflection and it would help conceal some of the minor blemishes in the wood.
With the help of the people in this thread, http://www.avsforum.com/avs-vb/showt...8#post12453418
, I had a procedure for a finish using rattle cans that would still yield acceptable results. It was basically 3 coats of spray satin black, lightly sanded, then 2 coats of clear polyurethane and another 2 coats of satin polyurethane. The end product ended up looking pretty good, if you look up close you can see very slight inconsistencies in sheen, but looking at it a couple of feet away it looks clean. Overall I'm happy given the tools I had to work with. Fiance even said it looks store bought
. The pedestal, pedestal legs, back and bottom are finished in spray on truck bed liner. This product looks real good too, I would be very happy to have the entire box finished in this as well.
Below is a pic of the final box:
So far after listening for a few minutes it sounds pretty good. Going from my Paradigm PDR-10 to this is quite a change. I immediately noticed that in music the instruments down low were much more defined. Movies were also much more impressive, but of course this new beast introduced a bunch of rattles in the room so now I gotta work on those. Just have a quick calibration using the receiver signals right now, I'll calibrate with Avia later this week to get it ironed down.
Thanks for reading.