DIY Speaker cab.

longi

I'm thinking about making my own oversized 1x12 speaker and so far I'm already agonising over wood choices for the cab. I'm actually toying with the idea of going with pine over Balitic Birch ply for no particular reason really. Would there be any real benifit for builing a cab with pine over Birch ply? Then there's the thickness of the wood. 15mm or 18mm?

ecc83

ICBM has often told us that much of the character we love about guitar cabs comes from the flexing of the plywood used in construction. This makes perfect sense to me in a 4x12 but I am not so sure it matters in a 1x12 because they usually use the same thickness of ply, 18mm and being much smaller panels they will be much more rigid. Logically they should tailor the panel thickness to the cab size!

But there is absolutely no "science" that I can see in gitcabs! For given drive unit it is all cut and try (and if the "arty" dept don't think the finished dimensions are quite "fen sui" it gets changed!)

Bottom line? You could build a 1x12 out of reclaimed pallet wood and it would sound ok IMHO! (but not a 4 by).

Dave.

ICBM

It definitely seems to matter less with smaller cabs, but I wouldn't discount it entirely. Ply sounds 'tighter' than pine to me, even in a 1x12". The thicker the material the less noticeable it is and the 'thicker' the tone as well - so I would pick based on what kind of sound you want, or music style. The two extremes would probably be something like country where you want an open twangy sound (use thin pine) or nu-metal where you want a solid bassy tone (thick ply).

You definitely want the baffle to be ply not pine whichever you use for the shell, by the way. The thinner and less tightly-mounted you make it the more resonant the sound will be and the more prone to overtones, which can be good or bad! Old Fender Tweed amps have a thin ply baffle that's only lightly attached to the cabinet, if that helps...

ecc83

Whatever you end up making the cab from I suggest you make the rear panel in 3 equal parts so that you can experiment with open and closed back versions (you could try a slit across the back, reduced panel size, of 5 -20mm and get a vented effect?)

Another trick it to make a cab as big as practicable then try blocks of expanded polystyrene inside to reduce the volume and "tune" the cab....Oh yes! Wasted a LOT of my life experimenting with speakers! Mostly for hi fi and PA.

Dave.

robinbowes

ecc83 said:

ICBM has often told us that much of the character we love about guitar cabs comes from the flexing of the plywood used in construction. 

It's the other way round - ply is stiffer than pine. Pine cabs resonate more.

R.

longi

Thanks for the replies. There's some interesting info there. I play mainly classic metal and modern prog. So maybe ply would be the way to go plus it would be cheaper.

@ecc83 I was indeed thinking of making the back in 3 parts for that reason!

@ICBM. I was panning on making the cab 630 x 500 x 300 so it would be on the large side. I'm looking for as big a sound as I can without going up to a 2x12. So the question is do I go for 15mm or 18mm?

ecc83

robinbowes said:

ecc83 said:

ICBM has often told us that much of the character we love about guitar cabs comes from the flexing of the plywood used in construction. 

It's the other way round - ply is stiffer than pine. Pine cabs resonate more.

R.

I was really making the more usual comparison between ply and MDF or chipboard. Both of which are denser and more rigid than ply. "Pine" is blanket term that could  apply to a pretty open grained lightweight timber to the very dense, hard as nails Pitch Pine!

Dave.

Danny1969

The denser the material the more low end it will have. MDF is ideal and cheap. 18mm works very well. My own 1 x 12 " is quite oversized and sounds great. You can play with open \ half open easy enough, mines very open as I like to keep beer in it

longi

I already have an mdf cab but I don't really like it hence this project. in fact I might use it as a donor for parts. I think you've swayed me towards18mm.

Next up then... Do dovetail joints make a great deal of difference in the overall sound of a cab? I know it'll make it stronger butt from a sonic perspective is there any real benefit?

robinbowes

ecc83 said:

robinbowes said:

ecc83 said:

ICBM has often told us that much of the character we love about guitar cabs comes from the flexing of the plywood used in construction. 

It's the other way round - ply is stiffer than pine. Pine cabs resonate more.

R.

I was really making the more usual comparison between ply and MDF or chipboard. Both of which are denser and more rigid than ply. "Pine" is blanket term that could  apply to a pretty open grained lightweight timber to the very dense, hard as nails Pitch Pine!

Dave.

Yes, but both are more resonant than plywood

R.

ICBM

Danny1969 said:

The denser the material the more low end it will have. MDF is ideal and cheap.

For making a bass bin or a studio monitor where you *don't* want the cab to resonate and contribute to the tone, yes.

longi said:

Next up then... Do dovetail joints make a great deal of difference in the overall sound of a cab? I know it'll make it stronger butt from a sonic perspective is there any real benefit?

I see what you did there .

Probably not given the strength of modern glues. Many of the well-known commercial cabs use rebate joints. Proper dovetails are very rarely used, more often it's parallel finger joints if there is any interlocking.

longi

ICBM said:

Danny1969 said:

The denser the material the more low end it will have. MDF is ideal and cheap.

For making a bass bin or a studio monitor where you *don't* want the cab to resonate and contribute to the tone, yes.

longi said:

Next up then... Do dovetail joints make a great deal of difference in the overall sound of a cab? I know it'll make it stronger butt from a sonic perspective is there any real benefit?

I see what you did there .

Probably not given the strength of modern glues. Many of the well-known commercial cabs use rebate joints. Proper dovetails are very rarely used, more often it's parallel finger joints if there is any interlocking.

Hah! I missed a word out! ok interesting to know. It looks like there are a few things to think about then. Thanks!

ecc83

Finger jointed construction is something people expect to see as a mark of "quality" . As has been said, with modern glues it is of dubious merit, I certainly would not go to the expense of buying the necessary kit!

If you can cut the panels to perfectly flat, square edges, PVA and a #8 screw or three will be fine. If you can't most DIY stores will cut to size for you or you can do your best and use an internal 25x25mm Ramin rail then fill the gaps!

"Proper" speaker cabs are supposed to be airtight but this is only Rock 'n' Roll.

Dave.

longi

[quote="ecc83;625414"]Finger jointed construction is something people expect to see as a mark of "quality" . As has been said, with modern glues it is of dubious merit, I certainly would not go to the expense of buying the necessary kit!If you can cut the panels to perfectly flat, square edges, PVA and a #8 screw or three will be fine. If you can't most DIY stores will cut to size for you or you can do your best and use an internal 25x25mm Ramin rail then fill the gaps!"Proper" speaker cabs are supposed to be airtight but this is only Rock 'n' Roll.Dave.[/quote

Ah cool. I won't bother with dovetail joints then. I can get the boards cut on site so they should be straight. Happy days!

Travis Perkins can also get Baltic Birch ply so they say but have to order it in. 18mm is £50 so 15mm should be around £40. I might go for 15mm purely as it'll be easier to handle in an 8x4 foot format.

Dalefty

A mate of mine made an absolute fortune - well into the few millions, by casting cement housings for speakers, now it's not the sort of thing you would want to do for speakers that you plan to move on a regular or semi regular basis, bu due to the extra mass and the amount the vibrations are cut down by, the quality of the sound the speakers produce is improved immensely, my mate did they as a way to earn a couple of dollars wile at university - his farther worket wity cement so he jnew his way around and how to cast cement, and by the time he had finished university in his early 20's he was a multi millionaire, and looking at selling the company he started at university to retire.

DaLefty

longi

As an experiment I got the guys a work to cut the cab panels out of some premium 18mm ply to see what it sounds like. It might sound ok it might not although I suspect it'll be a step up from my current Harley Benton MDF cab! It it sucks I'll bite the bullet and order the Baltic Birch ply.

I made the bigger than previously stated at 630mm x 300mm x 550mm. It's now about big enough for a 2x12 but I'll stick with the 1x12 for now. It can always be modded to fit another speaker later.

longi

So what was going to be an oversized 1x12 cab has now turned into a 2x12 cab! I can ujst about squeeze two in there and as I have 2 spare 16 ohm speakers doing nothing I thought I might as well!