Discussion on what materials to build speakers out of

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
frugal-phile™
Joined 2001
Paid Member
Cold rolled steel can make a fine enclosure...

PVC pipe works too...

Boomtube.jpg


http://www.t-linespeakers.org/projects/sampson/index.html
http://www.t-linespeakers.org/projects/davidduke/index.html
http://www.t-linespeakers.org/FALL/toobz/index.html

dave
 
You are freaking kidding me ... Red Green version 2.

BTW I can do this but I wont because of the work it will take.
There is a 2-3 ft diameter white oak that someone knocked down by my house.
Been cut into 4-5 ft sections too. Get 2 of those and start whittling away a nice 15-18 inch cavity ... get down to 2-3 ft depth. Then drill an oblique hole till you see daylight. Of course you can hand peel it or use it with the bark. Then fit your drivers on the sides and the woofer on the top.
Of course you can do it all upside down also, sit the thing 6 inches up on a few legs and let the woofer fire downwards.
Imagine, 2 pieces of 3 ft dia, 4 ft tall white oak as your "speakers".

Of course you knock down the nearest pine tree for the rear ...

Cool.
Srinath.
 
Yea my mechanic (who actually has a 2ft dia pine trunk lying about) wants to burn the whole tree with drilled vent hole and a axial hole so it will burn side ways with forced air from the vent hole etc ...
I suspect a stupid project comming sometime. Either that or we burn down the house.

Cool.
Srinath.
 
I'm just designing cabinets for a pair of subs and after taking delivery of my baltic birch ply it occurred to me that if the aim is to increase the resonant frequency of the panels one option we have available is to put tension in the panels by bending then into a curve.

One very simple test with any piece of easily bendable ply will demonstrate that the resonant frequency rises with increased tension and I suspect the amplitude of any ringing will be reduced also.

Does anyone here have any experience or advise with this method

mike
 
Last edited:
Mike, good idea - but...

ask anyone who builds glider aircraft or race boats. Laminate rounded structures of multiple layers of thin plywood and you get an incredible stiffness vs. weight ratio.
You´ll want to invest in a firm making clamps, though...if you think you can guess how many you´ll need - take drugs and think big.:D
 
Last edited:
well - how's this for an idea . . .

make the cab in the regular way - then when the all the glue has dried etc take some heavy duty threaded rod who's length is the same as the width of your cabinet.

Add two nuts to the rod - one each end. Then position the rod in the centres of the sides and begin unscrewing the nuts. This is an easy way to apply tension to the two sides of the cabinet.

I think because the ply is so stiff originally even a small amount of movement will give a good amount of tension.

How's that sound ? . . . . . ( the idea, not the box ;) )
 
Hmmm...that would show you how shear forces can wreck glued joints! But threaded rods are a secret wunderwaffe! A normal clamp has a span of 15-20cm, two lengths of 2"x2"hardwood, holes at the end and clamped together with threaded rods, washers and a spanner - two ft. are not a problem.:)
 
frugal-phile™
Joined 2001
Paid Member
Bending the playwood to put it under tension will increase its resonant frequency. This has been brought up before. You can either make it convex by using shaped braces (as done for instance in the B&W Nautilus 800 series), or as in the previous post, tension it with something like ready rod. If the latter, use BIG washers and you may find a need to damp the rod inside the box as it will become as a tensioned guitar srting and itself cause secondary issues.

In a subwoofer, where higher than the passband is quite easy to acheive it may just be added complexity.

dave
 
<In a subwoofer, where higher than the passband is quite easy to achieve>

Dave, it´s a pity neither of us is queer, otherways we´d marry. Charging crazy money for sub enclosures not resonating where they never reach in the first place...money for nothing and the chicks for free! (OK, I´m a DIY hardcore, so I don´t need to be that clever)
 
No freaking kidding

No kidding, I pulled a XS650 crank apart this way - used regular bolts in the 5/8th flavor, all the nay sayers on the xs650 site promptly shut up.
I then proceeded to rephase to 277 degrees and weld up the crank ... yet to get inside a motor that crank.
Anyway, My guess, a pair of 5/8th bolts was good for ~4-6 tons of force.
Cool.
Srinath.

well - how's this for an idea . . .

make the cab in the regular way - then when the all the glue has dried etc take some heavy duty threaded rod who's length is the same as the width of your cabinet.

Add two nuts to the rod - one each end. Then position the rod in the centres of the sides and begin unscrewing the nuts. This is an easy way to apply tension to the two sides of the cabinet.

I think because the ply is so stiff originally even a small amount of movement will give a good amount of tension.

How's that sound ? . . . . . ( the idea, not the box ;) )
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.