Quick question about port tubes and speaker sealing in a cab

[Rob22315]

I've got a 115 cab I like with a good quality speaker - nothing boutique but works for me. It's a Peavey 115BX BW.

The port tube is cardboard and appears to be intact although the interior black paper has just started to peel a little. I just got a plastic replacement, is there any major benefit to replacing the old cardboard port tube with one made of plastic that's the same size?

Also, the speaker isn't sealed against the baffleboard, it's just bolted on. Same question regarding weather strip sealing the speaker to the baffle board. I don't mind adding the stripping, just wondering if it will make a difference.

Finally, I just installed pop-in/out casters in the cab so i could roll it around. The caster tubes aren't capped so air can leak out of the cab, especially when the casters are removed. Is it worth trying to cap the top of the caster tubes?

There's no evidence that there's any whistling and no major change in the sound of the cab as near as I can tell but is it worthwhile making the above corrections?

[mikeddd]

Any air leak is detrimental to performance. A big enough leak changes the tuning of the cab.

IMO:

As long as the port tube is structurally sound, leave it alone. Don't let any peeling paper block the tube though.

The speaker might have a paper or foam gasket on the back (part that touches the baffle of the cab) that you cannot see with the driver installed. If it does not, some weatherstripping under there can help.

You should cap those caster tubes. Put a dollop of silicone over each one and you're done.

[HertzWhenIPlay]

if the cabinet is designed right, the material of your port should have little to no effect on the output of your speaker. like mikeddd said, if it's structural integrity has been compromised, go ahead and change it with a port that has the same internal dimensions. if you upgrade from paper to plastic it will prob last longer and that's about it.

Definitely seal the inside of the cab where you installed casters.
it might also be a good idea to caulk the inside seams of the cab, while you're at it.

As far as sealing your driver to the baffle board, just don't go too crazy and make it ugly.
If your speaker has a foam gasket on the inside of the lip and your cab is carpeted, then you might not even need to add anything there.
just my $.02.

[Rob22315]

Originally Posted by mikeddd

Any air leak is detrimental to performance. A big enough leak changes the tuning of the cab.

IMO:

As long as the port tube is structurally sound, leave it alone. Don't let any peeling paper block the tube though.

The speaker might have a paper or foam gasket on the back (part that touches the baffle of the cab) that you cannot see with the driver installed. If it does not, some weatherstripping under there can help.

You should cap those caster tubes. Put a dollop of silicone over each one and you're done.

Great, thanks for the feedback. I'll cap the caster tubes and add a seal to the speaker. The port is in good shape so I'll leave that alone.

There's no sealing on the speaker. I took it off when I repaired some minor surface damage on the baffleboard and noted the lack of a seal. I have to remove the speaker anyway to get at the tops of the caster tubes (unless I wanted to unscrew all of them which I don't).

[Rob22315]

Originally Posted by HertzWhenIPlay

if the cabinet is designed right, the material of your port should have little to no effect on the output of your speaker. like mikeddd said, if it's structural integrity has been compromised, go ahead and change it with a port that has the same internal dimensions. if you upgrade from paper to plastic it will prob last longer and that's about it.

Definitely seal the inside of the cab where you installed casters.
it might also be a good idea to caulk the inside seams of the cab, while you're at it.

As far as sealing your driver to the baffle board, just don't go too crazy and make it ugly.
If your speaker has a foam gasket on the inside of the lip and your cab is carpeted, then you might not even need to add anything there.
just my $.02.

Also thanks. The cab is carpeted but the baffleboard is not so there's really no seal between it and the speaker.

I'll see about caulking around the sides of the cab and the holes where the casters are installed as well.

[will33]

Peel and stick weatherstripping makes a good speaker gasket. Tighten it back down evenly and snug, just like changing a tire.

+1 to what these guys said about the ports. If the cab isn't lined inside do that while you have it apart. Mattress pad or quilt batting one or two inches thick. If it already has insulation or something it good already.

+1 to caulking and sealing the caster mounts as well, don't want air leaking anywhere but the ports.

[Rob22315]

Originally Posted by will33

Peel and stick weatherstripping makes a good speaker gasket. Tighten it back down evenly and snug, just like changing a tire.

+1 to what these guys said about the ports. If the cab isn't lined inside do that while you have it apart. Mattress pad or quilt batting one or two inches thick. If it already has insulation or something it good already.

+1 to caulking and sealing the caster mounts as well, don't want air leaking anywhere but the ports.

Thanks, the cab is already lined with fiberfil so I'm good there. Sounds like sealing the speaker and the caster mounts are in order.

[Rob22315]

I pulled the speaker tonight, caulked the casters, plugged the top of the caster tubes with some foam sealant I had left over, and added a seal to the speaker.

The cab sounds noticeably tighter and thumpier now. I won't lie and say it sounds like a whole new cab but there's definitely a difference. Thanks for the tips.

[fdeck]

Good call.

Sealing a speaker is vital. Small air leaks can create whistling or sizzling sounds that are hard to track down and can sound like something is loose, wrong with your amp, etc.