Introducing: The Pit Vipers (Ooh Yeah!!!)

[djg]

I lifted this from Lunchmoney's Speedster thread. He has the dowels going through the panels, but one could do front to rear braces between the panels at the woofer mount points, and use long wood screws to both mount the woofer and secure the baffle. That should settle things down.

[Serenitynow]

Hey Paul,
Any further progress on this project ?

[davidroberts]

Why not use 3-4 window braces that can be glued to all four panels, three with screws if you want the front baffle removable. You could cut them just shy of the depth for the front baffle and screw them in.

[Serenitynow]

Hey. Yeah. That explained it much better than I did. I could picture it I'm my head, but had trouble conveying the idea.

[a4eaudio]

I'd be hesitant to just wedge them in. A modified version of the above...use 4 to 6 one-inch dowels. Using a 1" forstner bit drill a hole about 1/4" deep into the back side of the front baffle, glue (clamp if possible) - they are now a permanent part of the baffle. Make them to 1/32" to 1/16" of the cabinet depth and screw them in from the back.

[Serenitynow]

Despite adding internal bracing, I think the one panel I've neglected is the front baffle.

In the past I used to just default to double-thick baffle with woofers 8" or larger. But with this particular design I have been making a conscious effort to keep weight down as much as possible. So far, it's a plain rectangular prism, about 70-ish Liters internal volume, using .75" stock all around; about as simple as I can make it.

But that baffle has a lot of holes in it; and I feel like the 12" woofer is playing it like a piano sound board. Don't get me wrong, I think what I've got here so far sounds pretty darn good and isn't ringing nearly as bad as it used to. But I can't help but think that I won't really know if I've done everything I could, unless I dampen or reinforce the baffle somehow.

Can't you just run a few strips of scrap between the front baffle and rear wall ?
Even if the front baffle is removable, just attach the strips to the insude of it and let them wedge against the rear wall. Maybe cut them 1/8" or so longer than the actual distance.
Put some gasket tape or weatherstripping between the baffle frame and baffle to help decouple and seal them as well.

[Paul Carmody]

Despite adding internal bracing, I think the one panel I've neglected is the front baffle.

In the past I used to just default to double-thick baffle with woofers 8" or larger. But with this particular design I have been making a conscious effort to keep weight down as much as possible. So far, it's a plain rectangular prism, about 70-ish Liters internal volume, using .75" stock all around; about as simple as I can make it.

But that baffle has a lot of holes in it; and I feel like the 12" woofer is playing it like a piano sound board. Don't get me wrong, I think what I've got here so far sounds pretty darn good and isn't ringing nearly as bad as it used to. But I can't help but think that I won't really know if I've done everything I could, unless I dampen or reinforce the baffle somehow.

[Paul Carmody]

That's a level of patience I'm not sure I possess.

[Paul Carmody]

You're correct. I was surprised how much it helped cut down on the vibrations. When you think about it, it's essentially battens that are 1/2 glued and 1/2 mechanically fixed.

[bassman_soundking]

The framing for the removable baffle should help with cabinet rigidity a little

[buggers]

I prefer every 4 inches. YMMV

[bassman_soundking]

Correct. And I'm really happy with it in this application. Also, I just noticed that it's seems to be another casualty of slow supply chain. Hopefully more come in stock sooner than later!

I have never done removable baffles on prior speakers, but I plan to on a current build.
I just dont know how many screws ( bolts?) to use or proper spacing to keep it from leaking or vibrating.

[bassman_soundking]

Correct. And I'm really happy with it in this application. Also, I just noticed that it's seems to be another casualty of slow supply chain. Hopefully more come in stock sooner than later!

Even xo parts seem to be in short supply right now.

[Paul Carmody]

It looks like the Peerless D27TG35-06

Correct. And I'm really happy with it in this application. Also, I just noticed that it's seems to be another casualty of slow supply chain. Hopefully more come in stock sooner than later!

[Paul Carmody]

On the subject of bracing

As I mentioned earlier, this cabinet definitely needs some bracing. My go-to is usually scraps of MDF, 2-3 inches wide, jammed/glued between walls. So that's basically what I did here.

I tried to tie in the back walls and the top as well. Could this be improved? Yes! In fact, I invite anyone out there who builds this design to experiment with different ways to give the cabinet some rigidity and raise the resonant frequency. (Or, if you're just good at CAD and want to draw something, I'd be interested to see that, too)

Here's my basic process for adding bracing:
1. I knock on the cabinet wall with my knuckles
2. Then I wedge the piece of MDF in place
3. I knock again on the cabinet and listen for the pitch to go up.
4. If I like the spot, I apply some glue on either side and wedge it back in
5. sometimes I'll shoot a brad nail in from the outside to hold it in place while the glue dries--although that takes some pretty good aim.

Also, you probably also notice a strip of hardwood around the inner perimeter of the front edge of the cabinet--that's for having something to screw the baffle into. Oak on the top + bottom, and maple on the sides, if anyone cares. Doing a removable baffle is actually a lot of extra steps, and somewhat of a hassle, but it's worth it in the long run as I can keep cutting new baffles to experiment with different driver combos.