My Dual RL-p15 Sealed Design

**Bent** · **02-14-08, 10:35 AM**

This is my intention for my dual 15" RL-p in a sealed config.
2 - D4 RL-p's in a box that stands 46" tall, and 22" by 22" wide.

I'm new to sketch-up, but was wondering about your opinions,
I'll be using my old Adire Audio ADA-1200 to drive it wired for a combined 4 ohm load.

The enclosure will have two internal braces with approx 6" space between each brace, and the front and rear baffles will be tied together with 1/2" dowels to elliminate resonance.
The sketch doesn't show it (again, I'm new to sketch-up), but all walls are to be doubled up 3/4" mdf, including the front baffle which the drivers will be mounted. I intend to recess mount the drivers approx 1/4" in for aesthetics mostly, and the ADA-1200 will sit on the back at a convenient height.

on the plinth, the total height will be approx 49"

**Geoff St. Germain** · **02-14-08, 02:08 PM**

Looks good. That should be a substantial enclosure. I can't wait to see the build progress.

**Bent** · **02-14-08, 02:20 PM**

I have the rear panel, (doubled up), each side panel including doublers, and part of the doublers on the top and bottom in place so far - if it ever warms up a bit then I'll continue.

**Mike P.** · **02-14-08, 02:36 PM**

Make sure you take lots of build pics! What are you going to finish the cabinet with?

**Bent** · **02-14-08, 03:39 PM**

I'm not sure about the finish, we are still developing the rec-room in the basement, so I'd prefer the finish to match my furniture (except we don't have the furniture yet).
If I get brave, I'll try veneering it.

**Mike Cason** · **02-23-08, 07:05 AM**

Bent,

My dual sub is almost indentical in box dimensions as your proposed sub. Mine is 39" tall, 18" wide and is 20" deep, 1.25" thick walls with the internal bracing. I have a large 2" x 2" brace across the front of my cabinet behind the baffel and between the drivers to both secure the baffel and cabinet as well as reducing resonance. It is also internally braced. I hope to have this one finished next week.

I'm at about 5 cu ft. with 4 passive radiators. I'm lining it with 1.50" eggcrate acoustic foam. This one will be the sister sub for the one shown in my avatar. I'm excited about having two of these in my HT.

You should be very happy with your results. I chose the black "Slate" Pionite laminate finish as it matches my other sub, the mains, TV, and equipment rack. Your finish coat will increase your WAF factor if it matches your finished room. I also have elegant black snap on grills which can be seen in my signature links. Post your pics for the rest of us when you are done!

Have fun,

Mike

**Sonnie** · **02-23-08, 08:22 AM**

Looking forward to seeing some progress.

**mlstrass** · **02-26-08, 12:03 PM**

My only "advice" which is too late now, would have been to use Baltic Birch or Trupan Ultralite to save weight as that box will be HEAVY when it's completed.

Looking forward to seeing pics...

**Bent** · **04-01-08, 09:43 PM**

here's the first construction pic - it's not much, but I had to prove that it really does exist.

**a1161979** · **04-04-08, 03:56 AM**

Looking good... Should be interesting to see it finished, havnt seen many sealed projects of late so its good to see, plus im interested in how it will perform

**Mike P.** · **04-04-08, 08:11 AM**

Take lots of pics, Ben!

**Bent** · **04-04-08, 08:52 AM**

I won't be taking too many, I don't want to show off my poor carpentry skills. But I will be sure to include the important steps.
I have glued down the first brace, and tied it to the rear wall with small mdf blocks, and also installed the same blocks to tie the second brace to the first.

My kids have offered to help paint it, I thought that was a good idea until they started brainstorming about drawing little speaker shapes all over it.

**Bent** · **04-04-08, 09:55 AM**

Seems I have more time today to work on it than I thought... 'cept I'm taking two of my three kids bowling this aft.

I wish glue would set faster when it's cold- it's about 0º Celsius in my uninsulated shop.

**Mike P.** · **04-04-08, 09:59 AM**

You might want to read the directions on the glue you're using. I don't know of any wood working glue that can be used at that temperature.

**Bent** · **04-04-08, 10:28 AM**

I've used it before at lower than optimum temps - working time just increases.
working bond strength usually in a couple hours - but with low temps it's more like 8-10 hours.

**Bent** · **04-05-08, 12:17 AM**

I'm ready to fasten my front baffle (doubled up 3/4" mdf with two 14" holes cut in).
I don't want to do this until I devise a way to make my plinth.'
I'm looking for suggestions, it will need to be strong enough to support approx 200 pounds of subwoofer box when the subwoofer gets tilted upwards into standing position. I have some ideas, but I'd like to hear any suggestions prior to me saying what I'm thinking.
Heres's a closer sketch.

I was thinking of finishing the enclosure in light maple or birch ply, of about 1/8" if such exists. The vertical sides will be 1/2" quarter round rather than the square edges I've shown, and the top will be somewhat more decorative too. I'm hoping the plinth will match.

**Owen Bartley** · **04-06-08, 05:07 PM**

Ben don't worry about your carpentry skills, the bracing looks awesome! And your design is very cool too. I'm a fan of boxes over tubes, and with good sturdy boxes you just can't go wrong (in my opinion at least). Keep taking pics, you're off to a great start.

**sandermi** · **04-06-08, 05:18 PM**

Great design-what is the software used for the 3-D visual?

**Bent** · **04-06-08, 10:01 PM**

I used shetchup (google) for the 3D drawings
I'd atatch the 3D file, but the forum software won't allow it.

**Bent** · **04-06-08, 10:28 PM**

I guess I should have posted some info about the subwoofer that this one will be replacing, as this is my second project.
I had previously built an AS-15 klone, but with a single voice coil 15" 4 Ω BP-1503 driver and a Adire Audio ADA-1200 plate amp, I had since induced "mechanical failure" on the BP-1503 during enthusiastic playback and replaced it with a 15" dual 4 Ω RL-p driver.

there is absolutely nothing wrong with this subwoofer, but I have this second D4 RL-p sitting around and needed to put it to good use.

**Bent** · **04-06-08, 11:02 PM**

Another post, I tried and tried, but I'm just not happy with the fit of the front baffle. The cuts are dead-on, the circles are acceptable, but when I laminated the two layers together they "walked" slightly askew prior to setting. This will make the front a tad wonky, and enough so that I will always know that it was less than acceptable. I'm OK with less than perfect, but I'm not OK with less than acceptable. I won't be able to do a proper round-over with this, nor can I adequately rabbit the edge to put quarter-round in.
I'll have to put this project on hold for a while, as I have a big one-year warranty check on a SF6 circuit breaker coming up this week. It will be eating up a fair bit of my time.

mine is a 230Kv unit at 115KV used as a circuit switcher rather than as a breaker with pre-insertion resistors to control in-rush current when energizing this: A 200 MegaWatt power exporting transformer c/w 3φ phase shifting transformer.

But I digress.

**a1161979** · **04-08-08, 11:43 PM**

Quote:

Bent wrote:

Another post, I tried and tried, but I'm just not happy with the fit of the front baffle. The cuts are dead-on, the circles are acceptable, but when I laminated the two layers together they "walked" slightly askew prior to setting. This will make the front a tad wonky, and enough so that I will always know that it was less than acceptable. I'm OK with less than perfect, but I'm not OK with less than acceptable.

Somebody needs help

Less then perfect as opposed to less than acceptable

You guys crack me up sometimes

**a1161979** · **04-08-08, 11:44 PM**

Your son is simply gorgeous... The port is the side of his head though, woundn't want him to do a sealed vs ported comparision would we :raped:

**Bent** · **04-09-08, 10:31 PM**

A woodworker friend suggested I try body filler first - it seems to be working...

but, (see below.)

My driver holes are a tad too narrow...
It's never fun having to enlarge holes, but I'm going to have to install some stock to help locate the center of a circle (that isn't even there), and re-route about 1/8 of an inch larger in total. I'll investigate the taper of the driver baskets and see if I can get away with a simple chamfer.
But it's shaping up...

**Bent** · **04-19-08, 12:55 AM**

as it develops, reality takes a front seat to good intentions,
a design change w.r.t how it gets finished became a necesity, otherwise it wouldn't get completed at all.

and so far - including priming and some of the 1/8" oak ply to function as a decorative "tombstone" to somewhat recess the drivers is where I stopped tonight.

The grey primer will soon be dark grey textured paint, and each vertical edge will have some corner molding applied.

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