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-   -   Speaker cab insulating and reinforcement (http://metaltabs.com/forum/showthread.php?t=29842)

Soulinsane 2006-05-07 02:35

Speaker cab insulating and reinforcement
 
I finally found a Randall XLT cab for a good price 2 weeks back at a local music store. I bought it for $300. It sounds worlds better then the damned Crate cab I had and is designed for my 300W Cyclone head. It is rated at 280W, 4x12 Celestion V30s, 3/4" birch, 4/16 OHM mono, 8 OMH stereo and was a steal at $300. I hauled my gear to the store to try it out the day I bought it and also took the back panel off to make sure it had V30s.

I realized that I've always invested in good instrument cable and connectors ( Mogami 2524 and Neutrik connectors), but have never looked into quality speaker cable so I decide to buy some good speaker cable and connectors for my new cab. It really does make a difference to have good cable, connectors, and solder joints. I did my research and found yet again Mogami cable to be about the best ever cable with God like low capacitance and resistance. I decided to buy Mogami W3103 2/12 AWG conductor speaker cable ( avoid 4 conductor in quad configuration. Its good for triamping only and not for short runs from a amp head to cab ) and G&H Megafoot .500 connectors. I build my own cables btw. I do better solder joints then anyone or thing I've ever seen.

Then I started to wonder.... What about the wire inside the speaker cab? Is it copper core strand? What AWG? Whats the point of nice speaker cable if the stuff in the cab isn't up to grade? So I open my cab and was not surprized to find cheap ass 20 awg aluminum wire connecting my nice Celestion V30s :mad: Back to research....

After some more research I found out that I might need to take a second look at my cab to make sure the speakers were bolted all the way through the baffle ( not just screwed in ) to insure they are sealed good, that everything was properly sealed air tight, and was turned on to the ideal that added sound insulation inside my cab will tighten my responce.

This is what I found. The speakers were mounted correctly through the baffle but I torqued all the mounting heads to make sure nothing was lose or uneven. As I said the speakers were mounted correctly. Even though Randall did use quallity materials on this cab and did build it as tough and leathery as a cheerleaders snatch, I found that it isn't sealed air tight. There is no seal on the back panel or on the handle hardwear and I can't be sure about the joints either as I don't see any calking sealant to insure a complete seal around the braces.

I am fixing the seal problem with calking on all bracing corners and with high dencity seals on the back panel and handles. I am fixing the wiring problem by installing 10 AWG strand copper wire. No need for using 2 conductor speaker wire inside a cab with so much room. That way conductors will not be close enought to build up a capacitance. I am also adding a few wood screws to the bracing as I only see staples holding them to the rest of the cab.

I also bought some egg carton foam that I'm going to glue to all inside surfaces except the baffle tomarrow. I have read that this destroys standing sound waves inside the cab and increases responce. People claim it makes a huge difference in there sound. Anyone ever done this? I'll find out soon I guess. If I don't like it I can always remove it.

xdislexicx 2006-05-07 11:48

sounds like you're on top of it... as for the foam... i'd think too much of it could dull the sound a bit and destroy the tonal qualities of the cab. when i popped the back off of my framus cab only the back panel had maybe 1/2" of foam-ish stuff on it. so not too much, but i bet that plays a huge role in how tight and clear this cab sounds. plus it already had pretty good thick speaker wire so i didnt feel the need to replace it like i would with an old marshall 1960 cab.

Soulinsane 2006-05-07 12:06

Yup, I'm glueing the 1/2" egg carton foam on the inside surfaces right now. Everywhere but the baffle. Should be just enough to kill any standing echo waves and tighten up the bass responce. I found the 72x34" egg carton foam at Walmart for $10 in the pillow bedding area. Far cheaper then other sound dampening foam, maybe not as effective and pretty looking, but I'm not trying to sound proof my cab and no one will ever see it. I only want to prevent standing sound waves from echoing and normal $10 Walmart egg carton foam does just that :)

I'll let you know how it turns out.

Soulinsane 2006-05-13 21:36

Well, this project has taken a little longer then I wanted it to because I kept coming across other issues to fix. I'll explain.

While insulating, rewiring, and making the cab air tight I was ( as I thought ) nearly finished. I was measuring and cutting foam for the back board panel of the cab and measuring the hole to cut for the phone jack plate when... I noticed I could see some light though the jacks :mad:


What is the point of a air tight cab if air escapes via the jacks?

I stopped, thought, and decided to fixe the problem by building a small sealed box around the jack plate. I built the box using soild pine, screws, wood glue, used chalking sealant on the inside corners, and let set for a day. Today I drilled holes and ran the wires through and use some chalking sealant around them. I secured the box around the jack panel using predrilled screws, used high dencity seals under the base and I also added chalking sealant around the base for good measure ;) To finish I glued insulation to the outside of the little box and it is now all drying.

Tomarrow, I will inspect everything again and hopfully get to put the back panel on my cab and be amazed its new tone.

Edit: I have been reading lately that you can line all surfaces but the speaker baffle of your cab and stuff the thing half full of foam to flaten your bass freq peaks ( boomy sounds ) and lower the freq range. I've only just lined my surfaces. I will try stuffinf extra foam in later and see if that changes anything. Seems lots of people do it do tighten up their cabs.

philkilla 2006-05-13 22:10

Those are some damn good points and ideas...I think I may look into it.

I have the newer Crate Blue Voodoo cab, but I've never cracked it open...I'm going to do so now and see what I find.

I'll keep in contact with you about this because it seems very intriguing.


EDIT:

I popped it open, and this is what I got:

All 4 speakers...

Upper Corner

Backplate Standoff???

It looks pretty well manufactured to me, but you seem to know a lot more when it comes to craftsmanship...so....

I don't know what guage the wires are, but I did write down the numbers:

Code:
LL29779 CSA AWM I A/8 105C 300V FTI OR TR-64 90C


I have no idea what the fuck that means, so I hope you do.

I went in and tightened up the screws for the speakers a tad bit more.

I was wondering about the inset where the handles are....as well.

As far as the "backplate standoff", I'm assuming its birch, but its attatched to a piece of plywood that is attatched to the inside of the cab...why plywood?

Now what can I do to improve this cabinet is what I want to know.

Soulinsane 2006-05-13 23:31

It can't be greater then 18 guage wire if its rated at 300V and from the pics it almost looks like you got two different guages of wire too. Mine did.

It couldn't hurt to get some copper standed ( not soild core ) wire; I'd say at least 12 awg guage and some female crimp connectors. Rewire it the same if you want but keep the wire short, uncrossed, and away from shit it could vibrate on. I might also get a tube of window/door sealant chalking to be sure of the corner seals. The speakers have their own seal so don't worry about them. Just give them a test twist with a screwdriver to be sure they are all torqued good. I also bought 17' of two sided 1/4" wide sticky strip desity seal for my handles and the back panel.

As for the jack plate... that is the weakest link in any cab as far as I'm concerned.

philkilla 2006-05-13 23:36

Quote:
Originally Posted by Soulinsane
I'd say at least 12 awg guage and some female crimp connectors. Rewire it the same if you want but keep the wire short, uncrossed, and away from shit it could vibrate on.


Local parts store right?

Quote:
Originally Posted by Soulinsane
I might also get a tube of window/door sealant chalking to be sure of the corner seals.I also bought 17' of two sided 1/4" wide sticky strip desity seal for my handles and the back panel.


Not sure what you mean here.

Soulinsane 2006-05-13 23:57

Pic of the back.

And another.

The back panel with isolated jack box.

Also what I mean about the seal stuff. These are all things I found at the Home Depot. Window/door chalking and sealing strip tape. They even have a very large selection of wire quality too.

arvina 2006-05-14 00:02

is this all really necessary? i can understand wire, and maybe a little bit of dampening, but man this is a little overboard. sometimes a little bit of those boomy sounds that can muddy up your sound can also make it really hit the chest and broaden the listening experience :p

Soulinsane 2006-05-14 00:14

The bass is still there and they still hit hard. Infact harder. Look up cab design. I'm going light compared to what some people do. Some people end up with 50% foam in their cabs before their cabs are tuned perfect. I will end with more foam before its over, I'm sure.

philkilla 2006-05-14 00:14

So how does it sound?

Soulinsane 2006-05-14 00:16

LOL, no ideal yet.

philkilla 2006-05-14 00:30

BTW, how much did all that stuff cost?

Soeru 2006-05-14 00:41

Jesus, I wonder what a cab carved out of a gigantic log of pure mahogany would sound like with barely any spaces inside except for the speakers and wire. br00t3l.

Soulinsane 2006-05-14 00:45

Quote:
Originally Posted by philkilla
BTW, how much did all that stuff cost?


<$30 total for everything + $300 for the cab.

Edit: As for my Mogami cable and megafoot connectors? Well, those cost a bit more but I make my own shit so not as much as if I bought them made.

philkilla 2006-05-14 05:52

Quote:
Originally Posted by Soeru
Jesus, I wonder what a cab carved out of a gigantic log of pure mahogany would sound like with barely any spaces inside except for the speakers and wire. br00t3l.


That would probably be insanely heavy...as far as weight and tone.

Slabbefusk 2006-05-14 10:30

When will people get that Vintage 30 4x12's are 240W and not 280W?

Just look at the celestion website!

Soulinsane 2006-05-14 11:12

Quote:
Originally Posted by Slabbefusk
When will people get that Vintage 30 4x12's are 240W and not 280W?

Just look at the celestion website!


I know what you are saying but Randall swears to fucking God that the XLT cabs are 280W. The V 30s in this cab look like 60W speakers to me though.

Btw, I get to put everything back together today :beer: Now if I can just find time to play it.

Slabbefusk 2006-05-14 11:38

I wasn't trying to flame you or anything I just don't get why all companies keep claiming Vintage 30's to be 70W then they're in fact 60W.

xdislexicx 2006-05-14 12:01

hell framus is claimin they're only 50w... my dragon cab has a quad of v30's and it's 200w mono or 100w per side stereo on the panel. :p usually speakers can handle a little more than what they're rated for anyways.


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