My RSS390HF End Table Sub Build

[DIYNut42]

Sometime last year I aquired an RSS390HF from forum member RightBrained. I built a temporary 5 cu ft box for it from 3/4" MDF just to try it out. Sounded decent, but it was just a temp job.

After getting ahold of a Bash 300S, I decided to make it into an end table sub. I messed around with the enclosure in WinISD for a while until I came up with something I would be happy with. I ended up with 6.5 cu ft tuned to 17Hz with a 4" precision port.

Since it would be an End Table sub I wanted to go with a rectangular shape, something nice for the top, mabey some trim on it, and feet to make it look more like a piece of furniture. Since I only have a girlfriend, and she doesn't live with me (yet), I don't have to worry about WAF much right now. :D So I decided instead of down firing the sub, I would have it forward facing. Seemed a shame to hide the sub since they are easy on the eyes IMO.

I ended up with 21.5 x 21.5 x 26.5 internally to net me roughly 6.5 cu. ft. after port, bracing, driver, and wall lining displacement. I started out with 3/4" MDF for the main structures top/bottom/sides. The front baffle is an inside layer of 3/4" MDF and outside of 3/4" birch ply glued and screwed together. All joints are b.u.t.t. joints glued with Titebond, and screwed together in crucial areas.

Below is a picture of the front baffle attached to one of the side walls and the bottom panel, and a picture of the 1/4-20 T-Nuts on the reverse side. The T-Nuts were drawn into the MDF using the screws and washers after dabbing a bit of Gorilla Glue under them to set them in place. They wont be budging any time soon. *Sorry for the poor photography. All pics were taken with a cell phone, and sometimes there was poor lighting.*

[DIYNut42]

Re: My RSS390HF End Table Sub Build

For the internal bracing I used three 3/4" MDF window braces. The middle brace has 4 extra spokes running from the center 45 degrees to the outer corners. I center of the first 2 braces coming from the back also support the precision port. Each brace also has a 1" hole cut consecutively through each verticle and horizontal brace spoke to support four 1" dowel rods which run from the front baffle to the back.

All bracing is glued and screwed to all walls, and an extra long screw was run through all four walls at each mid point of the window bracing to ensure the subs wall, bracing, and dowel rod will be attached together very snugly. While moving the enclosure around durring the build I could grab it by the dowel rods to pick it up without one creak or budge at all. Very solid.

After running the port through the bracing I applied a small amount of epoxy where the port and MDF meet. After getting all the bracing in place for the final time I went ahead and assembled all the ports internal parts permanently.

Here are pics of a window brace, port, and a dry fit of all the internal parts.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

After talking it over with a few members here, I had decided it would be ok to center the port behind the drivers magnet. I cut just a standard hole in the back panel to accomodate the outer flare, and the flare is surface mounted to the MDF.

Too keep the size of the sub down a bit, and keep the amp closer to the AVR, I remote mounted the amp in a quick and dirty birch box I built and painted black. So for the hook up terminal I chose a bottom corner, and made a hole for it.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

I decided after getting both of the sides attached, port fully assembled, and terminal plate sealed in, that I would do a test run. I clamped the top on to the enclosure and wieghed it down, mounted the sub, and ran some test tones and music through it. It didn't sound TOO bad, but I noticed a very hollow tone in some areas as well as sounding buddy, boomy, and peaky in others. That made up my mind about deadening the inside.

I stared off with lining the back panel with R-13 insulation, then slapping the top back on. I did this a few times and progessed forward to the front of the sub with the insulation until it started sounding better. At one point it started to sound a little too dampened, so I removed one layer of the insulation and switched to some 5/8" thick carpet padding.

I removed the driver to finish lining the remaining walls with that all the way to the front baffle, slapped the top on permanently, and gave it a good hum test inside. It sounded very dead so I went ahead with the build.

Below are pics of the internal damping material, and a little oops I had to fill because I got a little carried away while routing...

[DIYNut42]

Re: My RSS390HF End Table Sub Build

If you are wondering what that black, round, fuzzy thing is in a few of the pictures, its something I came up with to fix an oops. When I was figuring the internal volume I included a circular hole in all the braces that is the size of the O.D. of the port tube. Since the front brace doesnt support the tube I was just left with a hole there.

I have heard from many owners of this sub that there is very little mech noise from the drivers motor at all, but with a flared port opening directly behind the pole piece vent, I didn't want to take any chances.

So to fix the problem I tacked a piece of black auto carpet I had laying around to one side of the braces hole, put a dense amount of poly stuffing inside the hole, then tacked another piece of carpet on the other side. Kind of making a sandwich inside there to hopefully cut back on any mech noise escaping through the port.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

The terminal plate is just a normal rat-shack plate I found laying around. Nothing fancy, but nice and sturdy. I picked up a roll of the buyout Acoustic Research 12 AWG wire to use inside the sub also. Nice wire, but I found a few discolored places where it looked as though some O2 may have gotten to the copper. Thankfully it was only in the first few feet of it.

I took apart the terminal plate to detach the male push type connectors. I stripped back the plastic on the wire, trimmed off the fiber core inside the strands, and soldered the connectors to the leads. Then since I had some of PE's adhesive heat shrink laying around I decided to seal them up all nice and pretty.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

Heres where I got carried away with the build because I was excited to get it all together. So needless to say I didn't grab my phone much to take pictures. Especially since there was alot of glueing, painting, and staining involved.

While trying to decide what to do with the looks of it, I found that I still had some of the 1/4" Oak paneling left over from another project. Since that was what I used on the top and sides of my AviaTrix mains, and thats what this sub would be crossed with anyway, I decided to make them all match in a sense.

So I laminated every outer wall of the enclosure except the front with the 1/4" oak paneling. I also decided to use some trim on it stained the same mahogany color as the front baffle of my Trixies. So I went ahead and overlapped the paneling where the sides and back met, knowing it would be covered by vertical corner trim anyway. This gave me a nice solid 1" thick wall throughout the entire enclusure. If you knock on it with your knuckles it sounds and feels solid as a rock.

A 7 1/4" hole fit very snug over the outer port flange, so there was no need to paint the MDF around it black to mask any gaps. I also found some hard wood feet laying around that suited it well. So they got a coat of primer, and a few coats of flat black Krylon rattle can paint.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

The paneling has a nice grain to it, so I painted it the same way as I did when I used ti on the sides of my AviaTrix MLTL's. (That thread will also be finished soon hopefully.) Its hard to tell in these pictures but theres a nice black wood grain thats very visible to the eye even inlow light. The trim is all stained with Minwax Red Mahogany, and given a few light coats of semi-gloss poly.

Since it is an end table sub, I figured it will probably have a few drinks on it now and then. So I picked up some stone-like 18" x 18" vinyl panels at Lowes, primed the top panel, and attached and trimed them to fit. I did this before attaching the upper molding trim so everything on top would be flush and flat from edge to edge.

The upper trim is something like small crown molding, the lower is small base board trim, and the vertical runs are just simple corner trim.

These pictures were taken with the enclosure still on the 2-Wheel dolly for a reason... ITS HEAVY! With 3/4" MDF through out and 1/4" oak paneling encasing it I had expected it would be, but wow. With the driver installed we loaded it onto a shop scale we have on the farm, and its just a few pounds shy of hitting the 200 mark... :eek:

[DIYNut42]

Re: My RSS390HF End Table Sub Build

So now I wish I had the equipment to measure this thing. Even before I ran my Audyssey calibration I was very pleased with the way it seemlessly integrated with everything else. It's crossed at 80Hz using the LFE input on my Bash, and my Onkyo 608 recievers settings. I notice no nasty peaks at all, and my ears are pretty sensitive to peaks and resonances. So far Ive noticed no chuffing even at high volume. Speaking of volume, I have the volume knob set to around the 10 O'Clock position on the amp, and audyssey set it at -2 dB down from there. Yet, it has no problem rattling the walls and vibrating the couch when the first pod comes out of the ground on War Of the Worlds, or when the Enterprise slowly flys by onn the opening sequence of Star Trek. Also I never knew there was a sub-20Hz tone in the music that plays when you first turn on an Xbox 360. The picture that came off the wall, and I both do now though lol. Granted this is all in an 18' x 23' room which is fairly small by some standards.

Music is pretty good, but it's an LFE sub so I don't expect much in that dept. Audyssey crossed my AviaTrix mains at 40Hz so they take VERY good care of the punchy bass stuff (thanks Curt).

I'm mainly happy with how visceral the bass in movies is, whether its music in a movie or an earthquake or explosion. Its does it effortlessly, yet its invisible and non obtrusive. Instead of sounding like there is a sub by the couch, it fills the whole room with clean bass. Oh, and even at high excursion I can set a drink, or other objects on top of it without them budging. (Take that Tempur-Pedic!)

I'll stop going on and on now, and here is a final pic of the sub in its home. Don't mind the mess.

[greywarden]

Re: My RSS390HF End Table Sub Build

Great build, Excellent write up! Looks good to boot.

[bolland83]

Re: My RSS390HF End Table Sub Build

Nice bracing, nice build, nice finish! That thing is a monster in a gentleman's suit, well done.

[Steve Henry]

Re: My RSS390HF End Table Sub Build

Very well done!

[DIYNut42]

Re: My RSS390HF End Table Sub Build

Thanks for all the complements. I've built several simple car audio subs before getting into this hobby, but it took me hanging out here for a while to learn the ropes from you guys on how to build something more refined. So thanks to everyone who shares thier work and expertise here. Hopefully I will have the equipment soon to post some measurements.

[philiparcario]

Re: My RSS390HF End Table Sub Build

try other lowpass settings if possible 50hz ,60hz or 70hz may sound better then the 80hz. My rss390hz runs 18 to 50hz. of course 80hz may be the best setting.

[DIYNut42]

Re: My RSS390HF End Table Sub Build

Actually I was messing around with the settings tonight before work, and it looks like I was wrong. Audessey crossed it at 50Hz. I bet when I wrote that I was thinking of what I had it crossed at manually before running the set up. Makes more sense seeing as it crossed my AvaiTrix MLTL's at 40.