Sealing a cabinet

[metalchurch]

I've been wanting to seal my cabinet for a long time now, and I finally dove into it yesterday.
First thing I did, was I removed the handles on the sides and sealed around the cutout on the cabinet's side. I used clear caulking for this:
(Looks kinda ghetto, but it got squished out evenly when I tightened the handles down.


The next thing I did was measured the inside perimeter of the cabinet. There were some gaps along the entire outside of the cabinet where the front face screws onto the cab chassis...
You can clearly see the gaps along the inside edge if you look closely:

I used pieces of wood trimming like you have probably seen on the walls in your house. I used Flat pieces for the top and bottom.
I measured across the top and bottom(28-1/4"), and then installed them by pre-drilling my pieces,and screwing/glueing them in place:

I used corner trimming (triangle shaped to fit in corners), for the sides. They were approx. 27" long. I measured them after the top/bottom pieces were installed.
These were also pre-drilled, and screwed/glued into place:

This is what it looked like when completed:
Top Left Corner:

Bottom Left Corner:

*************************************************************
Before and After....




After I put it back together and it dried overnight, I fired it up today and I was immediately surprised at how much this simple modification tightened up the sound of my cabinet. I'm not talking about the low end either, it was almost like it "compressed" the sound a bit if that makes sense. I'm not going to compare it to an open vs. closed back cab, but it's along the same lines if you follow me.
I actually had to back off the low end on my EQ a tad bit, because it got kind of "woofie."

But I'm very satisfied with it. I'm sure that there are different ways and probably better ways of doing this, but it worked out pretty good for me, so I'm happy enough with the results.
Just wanted to share this with you guys in case one of you wanted to do the same.

Jeff, if there's anything that you'd like to add or comment on, please do, because I can change whatever on this thing. I know that you built cabs too, as well as some other guys on here. So if you have any suggestions, please share them with me.

Thanks

[Ron]

It probably sounds more "compressed" because with a sealed cabinet the speakers act as a tighter "spring". If there isn't a tight seal, the speakers will flop around more and can tend to modulate the mids and highs. With woofer/subwoofer cabinets a pinhole can make a difference in sound.

The only thing I wouldn't have done is use caulking. It can act as an amazingly strong glue after it ages a while, and if disassembly is needed for anything it could cause problems. They make a type of weatherstripping that is like a gray clay and stays fairly flexible over time. It will seal just as well as silicone or latex caulking. If you haven't sealed the rear panel you could use it there.

You've also helped the power handling of the speakers a bit by limiting their excursion.

[metalchurch]

I only used the caulking on the handles, the rest was glue and screws.
Thanks for explaining that to me, I understand now.

[lonewolf]

You should use a mitre saw on cove and quarter-round molding.

Cut them at a 45 degree angle so both pieces fit tightly into the corners.

Butt joints (as shown in your pics) work better with square or rectangular stock. You can get this kind of stock at Lowe's or Home Despot in the project section. Its a little more expensive than molding, but its a lot more precise material. It comes in birch, poplar, pine and oak in all different square and rectangular sizes up to 3".

[Banned]

butt joints, haha.

[Bloodsong]

Ron is right about it being more compressed. it will also project "harder" and more forcefully. be careful with mids in your EQ; by sealing the cab you just added alot more and the low end will be tighter and more focused. i dig mids, but too much can make you tone sound "cheap" and fake. Chad and I use a front loaded sealed back cab to record with because of the clarity and punch it has; it can however be a little overbearing at loud and live band settings if your not careful- and can get harsh pretty quick. on the bright side, everyone will hear you in mix lol....

[songsmith]

Home Despot.

Hey, leave my wife out of this! Just kidding, her tyranny benefits the bourgeois... my laundry is being done as I type this, so I can't complain.

I've done similar mods to PA cabs, though not with quite as much care. My buddies and I took our old Double Perkins bins (2 horn-loaded EV 15's per cab, approx. 48"H x 48"D x 66"L, too big for most doors), and turned them into front-mounted 2 x 15" scoops. We took a less-pretty alternative, setting a 2" x 2" brace front to back, and another 2" x 2" from side to side halfway down (to cut resonance and flex on the side panels). The large panels were all fitted with a glue-and-screwed 1/2" x 2" for the same reason, and most right-angles were braced with the 2" x 2" wood, as well. We sealed everything up with expanding foam in a can (Great Stuff, I think it's called), sprayed the inside with auto undercoat (cheap stuff you used to get at K-Mart with the spray paint), painted the whole shootin' match satin black, and there you were. Ugly, but somehow effective. We briefly loaded them with JBL's that sounded pretty good, but they mostly had the EV's, which I can honestly say were passable but cheap. I have a degree in Passable But Cheap. --->JMS

[CMOR]

I'm glad someone brought this up. I've been thinking about sealing my bass cab. But I don't want to make it irreversible. Just close up the ports, which can't be removed without some major damage. Any suggestions?

Steve

[Ron]

I'm glad someone brought this up. I've been thinking about sealing my bass cab. But I don't want to make it irreversible. Just close up the ports, which can't be removed without some major damage. Any suggestions?

Steve

If it's a factory bass cab with ports, you'll likely lose a lot or all of the sub-bass. Ports are there to add low end without having a huge cabinet. For bass it's either a large sealed cab or a smaller ported cab.

For a temporary attempt, anything that fits tightly into the port will work. You may be able to use the expandable rubber plugs they sell in automotive stores to repair rusted out freeze plugs in engine blocks.

[CMOR]

Not a bad idea. I'm mostly curious how it would sound. Thanks Ron.

Steve

[orangekick]

Not a bad idea. I'm mostly curious how it would sound. Thanks Ron.

Steve

What exactly are you trying to accomplish here?

[CMOR]

No particular goal, just seeing what it would sound like. Don't get me wrong, I love my tone. I'm just curious. But we all know where that got the cat...

Steve

[orangekick]

Excellent. Go for it.

I personally think that sealed bass cabinets are better for recording purposes.