"Thumper", my dual polk driver subwoofer...

jon s

I have always like the Dayton RS1202 subwoofer design. I wanted to buy one but shipping it to Hawaii was more expensive than the cost of the box (total would have exceeded $500... the price of living in Hawaii). I have built a couple of subs (a Dayton RSS315HF and a Dayton RSWS390HO) so I figured on tackling on building a near clone of the Dayton RS1202...

I was given a pair of Polk MM1240DVC drivers and had a spare Dayton SP-1000 amplifier, so I decided to build the box around that. One design change was that I made the sub amp enclosure with a removable rear panel in the event I wanted to change to another amp down the road without building another box. I punched the TS parameters into Bass Box Pro and came out with about the same specs as the Dayton box... 17" wide, 21" high and 27" deep.

To build the box, I decided to buy a table saw. A table saw makes life a lot easier for DIY. I got the DeWalt 7490 and bought the optional rolling stand to replace the flimsy scissors stand that came with the DeWalt. I should have bought the 7491, it would have saved me money, but I digress...

I picked up a couple of 4x8 panels and roughly cut it down to size. I then cut the MDF to my specs. The sides are double 0.75" panels. The inside panel is cut shorter so I can butt another against it to form the wall for the sub amp enclosure. I scalloped the insides to promote better airflow and glued T-Nuts to the insides...

jon s

I glued all the panels together. I then bonded all the seams and sanded them down. I waited a few days to make sure that there was no shrinkage in the bonded areas which would make the seams visible down the road. I prefer bondo because it is more sturdy than wood fillers, although it is a lot more messy to work with...

jon s

I made the base using the table saw to cut the 45 degree angles. I routered panels to make the grill frames. I used a/c filters for the grills. I painted the grill frames black with primer, sprayed Scotch 77 on it and glued the foam on. I then trimmed the foam to the edges of the grill frames.

I glued the base on the box and painted the entire box with Zinnser BIN Shellac based primer. The pictures show the upside down so I could paint the bottom of the box with the primer. I painted the inside of the box with primer as well...

So far, I figure the box is about a hundred pounds...

jon s

I painted the box with Rustoleum Satin oiled bronze. I came to the conclusion that satin was not a good choice. Using aerosols prevents you from getting a nice even finish. I bought some Krylon dull coat paint and sprayed it over the Rustoleum.

I had a minor but visible disaster. The clear coat had blushed on me. Some sections had a whitish look because of the humidity.

jon s

I sanded down the box and repainted the bronze and the dull coat. I had run out of the Rustoleum oiled bronze and used their Universal Oiled Bronze paint. It has a primer in the paint and also has a nozzle built in to the cap. I liked this paint. The new nozzle delivers the paint in a finer mist pattern which left a lot smoother finish.

I drilled two holes to insert the binding posts in the box. I offset the posts to the lower left corner to avoid any issues of it interfering with any larger future amp installations. I attached Dacron polyfill to the inside using the Scotch 77 adhesive.

I then mounted the rear panel and installed the amp. I moved the box indoors for the rest of the assembly because it was already too heavy to move around as it was....

I wired the speakers and installed it.

jon s

I ran into a problem here. The grills I built would not fit. The clearance between the driver and the baffle was a bit too tight. It was fine earlier but because I painted the frame, the tolerances was too tight. Plus the foam covering came out pretty ragged after trimming. Even using a new sharp Xacto knife caused the blade to snag here and there.

I am going to make a new grill with a cloth covering when time permits. In the meantime, I dragged the completed sub into the proper location, replacing the Dayton RSS315HF sub. The Dayton box is a 18" cube. The new sub is notably larger (and a LOT heavier, about 170 lbs).

The new sub does add a lot more bottom end to the sound. Watching Battle: Los Angeles shakes the room. But the bass seems more in the 20-25Hz range and the 30-50Hz range is notably lower in volume. I will have to play around with the EQ to adjust the sound to my preferences...

pitdogg2

Looks very good but one question Why T-nuts? Thought that was a no no for MDF. I'd do what the old timers did and also staple across them so they will not turn. I know you glued but will it also hold to screw torque? Some of my older boxes had T-nuts stapled across them and they never budged, but then again it was plywood. I've had them come out after trying to disassemble the driver and make a mess.

jon s

If you use Gorilla Glue with the T-Nuts, they are stuck on pretty good... I have never gotten one loose yet. Staples on MDF would probably be no good because MDF is a very soft composite. It cannot take much stress before it cracks or splits.

pitdogg2

well it looks very good job well done.

EndersShadow

So when you building a second one .

Looks VERY nice!

pitdogg2

EndersShadow wrote: »

So when you building a second one .

Looks VERY nice!

heck you couldn't afford the shipping from my house let alone half way across the pacific

EndersShadow

pitdogg2 wrote: »

heck you couldn't afford the shipping from my house let alone half way across the pacific

LOL.. not for me, for himself....

I've still got my DIY build to complete on my own, and its going to be more than enough for a week or so...

jon s

I bought all the wood and stuff for the build in January, but it literally rained every weekend since. I only got started on this about a month ago. I actually bought a pair of Polk DXi124s for the build but someone gave me the Polk MM1240s, which is supposed to be better. I still have another 500-watt amp, so theoretically I could build another cabinet and make another physically identical box.

What I need to do is to rebuild my Dayton RSS315HF-4 because the driver is stuck in the box with a stripped T-nut which is not secure. I want to make a candy red cabinet.

Conradicles

Very nice. I like it!

jon s

I finally finished the grill on "Thumper"...



I also finished my red sub...It is based on the Zaph Audio Subwoofer build... It uses a Dayton Audio RSS315HF-4 Reference subwoofer and a Dayton Audio SP-500 500-watt sub plate amplifier... The box is a 18.5" cube with a separate sub-enclosure for the amplifier. The total weight is about 85 lbs. The end result Qtc is about 0.630, which means the bass is very tight.

I primered the box with Zinsser BIN Shellac-based primer and sanded it down with 320 grit paper. I found some gaps and filled it with Bondo and resanded. I made sure that the seams were completely flat.

I then used several cans of Krylon Banner Red. My big issue was that the paint was drying before hitting the surface. This left the surface very coarse, like sandpaper. This was at about 8" away from the box. I had to get closer, about 5-6" to avoid this issue. This however lead to runs. I had to spray rapidly laterally to avoid the paint from running. I sanded between every few coats with 320 grit and the later coats with 400 grit. When I applied the final coat, I waited several days for the paint to cure and I used 600, 800 and 1000 grit. I then used rubbing compound, polish and then waxed the surface. The first and second pictures are closer to the real color of the red. Lighting really affects the camera shot.

I have an issue where there is a haze under the surface of the paint. The surface is super smooth but I can distinctly see a crazing or a haze under the surface. Also, the seams started to show. It looks like the Bondo shrank a bit leaving a line on the edge of the boxes. A high gloss finish is a LOT of work. It took me a month to finish this box, about 4X longer than just painting it with a satin finish... This gloss surface shows every flaw.... The build took about two months. My next project will be a 15" subwoofer in a vented 22" cube.

I really want a HVLP spray gun...

ken brydson

Love the red one! Nice work!!

westmassguy

Beautiful work on both!

drumminman

Impressive. That looks like it was a fun project.