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Discussion Starter #1 (Edited)
This all started a couple of years ago. But I didn't know it at the time.

When I first put together my basement theater, I was optimizing for floor space, and budget. Because of that, I only purchased one SVS PC-13Ultra. The idea was that I would get another PC-13Ultra the next year or so.

At that time, the room looked like this:









Time passed, and I was happy to enjoy movies in this room. But it was time for the next step. I knew that the room was pretty bad acoustically, and decided I would add treatments before anything else.

I built these over pretty much all of last summer, and, when finished, the room looked like this:

Front wall, entirely treated: (16 inches of Roxul SnS [8 inches, plus 8 inches air gap, really], floor to ceiling, 14' wide)



Walls (3 inches, plus 2 inch air gap), ceiling (8 inches, plus 3 inch air gap), back wall (6 inches, plus 2 inch air gap)



The room sounded much better, and REW and my umik were producing better and better graphs. But I couldn't quite get rid of a null, and knew the 2nd subwoofer was calling out to me.

But where would I put it?

When this all started, there was space behind the screen (the original intent). But, now that was occupied by a ton of insulation. Maybe the back corner? Hmph.

Maybe I could lie the cylinders on their side, and place them under the screen?

I wonder what else might fit under the screen? SVS PB-13Ultra. Obviously. Nope, I had 18 inches from the floor to the bottom of the screen. I wouldn't even be close. I wonder what else is available.

At some point, I realized that I could just raise my screen a few inches and I would be able to fit the Ultimax 15" knock down cabinet. Because that would *just barely* fit, it didn't occur to me to check the size of the 18" cabinet. Of course, it's only another 1/2" if I'm happy to turn the box on its side. Hmm... 18" instead of 15" for another 1/2" of raised screen height? Sure!

And so it began. (To be fair, there was a ton of other considerations...Stonehenge on it's side, built into the 16" front wall. Or, take down the front wall, build a couple of big Martys, and reconstruct the wall around them, etc...)

I grabbed an iNuke 6000 from someone here, and ordered 2 kits from PE (drivers weren't in stock at the time, though).
 

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Discussion Starter #3
Just to give some perspective on how well these boxes fit together, and how well they sand.

Here's 5 panels coming together on one side, all the dark stuff is dried glue:



About 15 seconds of sanding on just the front corner (80 grit)



10 more seconds



And done



A close up

 

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Discussion Starter #4
The fact that they fit together so well, and sand perfectly meant that I was willing to push on with zero filler.

Restore 4x. Great stuff. 3/8" nap roller, very thin coats. I chose to sand with 120 grit after each coat...probably not necessary.

Here's what it looks like after a single coat, and sanding with 120 grit. Very nice coverage for unprimed MDF!



And, all done.



 

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Discussion Starter #5 (Edited)
The drivers arrived!





With the driver in place like shown below, I used a punch with a hammer to mark the center of each mounting hole. Since the plastic ties made that impossible for two holes, I lifted, rotated the driver 90 degrees, and set it back down. I made sure the other holes lined up with the punch marks, and then punched the final two locations.



My makeshift drill press. This contraption is screwed to the wooden base (because otherwise, there would be no way to clamp it in place when drilling on the edge of a hole...). The 2x4 thing inside the cabinet is there to prevent blow-out of the MDF when the drill comes through the back. This worked extremely well. The drill guide itself has some slop in it...but it you are careful to press straight down, it does what it is supposed to do.



Using washers to hold the t-nuts tight



You can't see it, but I put a drop of gorilla glue on each t-nut before drawing them into the MDF.

 

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Discussion Starter #6
While the gorilla glue dried, I stuffed the box. I bought 2 5 pound boxes of polyfil from Walmart. I was aiming to use 4 pounds in each box. Fortunately, inside the box, there are two large "rolls" of this stuff, so I figured they were probably 2.5 pounds each. I used one whole roll to stuff the bottom half of the box:





Then, I used most of the rest to stuff the top half of the box, leaving room for the driver.





This was what was leftover from one box



Then, cover the polyfil with some netting



All trimmed up:



And, the last step before dropping the driver in...wire it for a 4 ohm load (black from one side, to red on the other), and wire-tie the wire so it doesn't move around

 

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Discussion Starter #7
And, the first one gets put in place



I wanted to make sure that my method of marking the driver mounting holes, and drilling, and installing was going to work before doing the 2nd one. So, now I get to go do it again on the second one...

Then the calibration and listening can start.
 

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Discussion Starter #9
Excellent thread, and craftsmanship to match. I enjoyed reading that.
Thanks! There's more to come when I start measuring response, and tuning, etc.

Oh, and we're neighbors (sort of), I'm also in Jersey (south, by Philly).
 

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Discussion Starter #11
Probably about 2 hours away; I'm in the NW corner of Jersey, Warren County to be precise.
It's amazing how "long" the state is. And, interestingly enough, at one point it was split into two, and for some bizarre reason that split wasn't as you'd imagine (North/South), but instead East/West...Go figure...

http://en.wikipedia.org/wiki/West_Jersey

Anyway, back on topic!
 

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they look fantastic. my whole house is almost as big as your listen area...i do hope i didn't overdo it going for dual 18s...
 

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Discussion Starter #13
they look fantastic. my whole house is almost as big as your listen area...i do hope i didn't overdo it going for dual 18s...
I think we've all come to the conclusion that there is no such thing as "overdoing it" when it comes to subs. Enjoy!
 

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It's amazing how "long" the state is. And, interestingly enough, at one point it was split into two, and for some bizarre reason that split wasn't as you'd imagine (North/South), but instead East/West...Go figure...

http://en.wikipedia.org/wiki/West_Jersey

Anyway, back on topic!
I never knew that and I've lived in this state almost my entire life!
 

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Discussion Starter #16
Come on Kevin! You don't expect us to believe you didn't hook it up and try it out... just a little bit? I'm looking for some quick listening impressions, and comparison to the previous setup. :)
I've been doing a build thread over on avs, so I haven't updated this one nearly as often. Sorry about that.



They are incredible. So much so that I've already sold my SVS PC13Ultra. It's out of the room.

First REW measurement. No tweaking yet. Red is single SVS, Blue is new dual 18s...



I think it really shows the benefits of dual subs, more than anything else... My two room nulls are greatly weakened.

Also, I'm flat to 15hz with sealed 18s. So much for them not reaching as low as the ported sub. ;-)
 

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Also, I'm flat to 15hz with sealed 18s. So much for them not reaching as low as the ported sub. ;-)
By their very nature, acoustic suspension alignments dig deeper while bass reflex have more output (all things being equal, of course). Your new subs having the ability to play lower is the expected response actually.
 
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