advertisement


Baltic ply for speaker cabinets?

Birch ply is currently at rip off prices across the UK. One of my nicer FR speaker pairs is made of 12mm poplar ply laminated with formica. Look great, sound great and lighter to move around than birch.

there's also several alternatives to birch worth exploring, I've used these guys in the past:

Winwood Products

Winwood Products is a timber importer, specialising in the distribution of technical panels & engineered wood products, manufactured exactly to your specifications
www.winwood-products.com www.winwood-products.com
 
Unfortunately a lot of the alternatives are even more expensive, like Stretek and a few others etc. I think they're only viable for trade users where availability has been the issue with birch ply rather than cost.

I'm doubtful prices will ever come back down like a lot of other things - time was any DIY woodworker would have a couple of sheets of birch ply hanging around just for projects or messing around with, those days are long gone.
 
matt j said:
Yes I mentioned it up thread, but have you seen the price?
Click to expand...
I've just had a quick look and given the current shortages Latvian birch ply, which seems to be around £125 per 18mm sheet is almost exactly the same as STREtek.
Both are pretty horrifying!
 
Baltic Ply IS birch ply. BUT not all birch ply is Baltic. The reason is that Ply made from birch grown around the Baltic is more dense. The harsh winters slow the trees growth hence higher density.

Birch/Baltic ply is usually graded, B, BB, S/BB for appearance. BB/BB is no imperfections on eother face, B/BB will have minor imperfections but only on 1 face. S/BB allows for patches on 1 face. For full explaination see link below (page 3):-


Baltic ply is often used for cabinets in touring sound systems because the density means greater resistance to damage by "Conan the Roadie" chucking them into the back of a transit van.

A lot of people say that MDF is actually better acoustically..... some have tried Laminating MDF with thin Birch ply on the outer faces.

Pays yer money etc.
 
Good old fashioned particle board is also recommended as being somewhere between the two. I followed Comeau’s recommendation by skinning particle board with the thinnest mdf I could find (6mm ?????) to provide a good surface for lacquering. It also allowed me to avoid learning how to use a router by cutting a bigger hole in the “skin” than in the particle board, thereby creating an inset for the drivers.
 
One thing people aren't mentioning associated with the extra cost is the number of plys. The expensive birch ply gear is 13 in 18 mm.
 
I use Birch ply all the time (guitar amp cabinet maker) & yes birch ply = baltic = latvian. It was sourced from russia until recently, then from latvia. So the area termed Baltic comprises of a few countries.

Before pandemic £42 a sheet. Now £92. Urgh. I use 9mm though & only for baffles & back panels, IE wouldn't use it for the cabinet 4-walled main 'shell' as it's a pain to fingerjoint, so I use 3/4" pine. But entirely different acoustical cabinet to a sealed hifi speaker: I want the pine resonance (baffle too) to -add- to part of the sound. I don't think you do though? I'd stay with mdf for speakers, after all that's what pfm resident spkr ex-pro James (Lord of Ergoland) used.

Capt
 
I’ve come across the idea of using two different woods for speaker cabs. a few times.

Birch Plywood front and back and the main case in MDF, seems to be popular.

Also sound’s easier to machine.
 
I wondered if sterling board might do for inner parts, or even outer bits that would be hidden, say back panels? A lot cheaper than real ply, but closer in properties to ply than say MDF.
 
Worth considering a quality 22mm chipboard or Egger p5. This is also available with a smooth coating (enables short term exposure to rain)
Caber manufacture "caberacoustic" this has an acoustic layer bonded to one side.

They're all designed for structural flooring so 2400x600mm. Still cheaper than the birch ply though.
Sterling board is strong and tough but I imagine it could be more lively than chipboard.
 
PaulMB said:
I've used "marine ply" for building several things, and it seems much better quality than anything else I've seen. There are no holes in any of the layers, the glue is supposed to be better, and it just looks and feels nicer (and heavier). Much more expensive, about 60% more than the ordinary kinds.
Don't know if it would be good for speaker cabinets, though. Just a thought.
But here, too, my carpenter friend says you have to be careful because it is not all the same quality.
Click to expand...
Marine ply is probably also Birch but uses a waterproof adhesive - hence OK for Marine applications. It probably uses a heat cured Phenol-formaldehyde resin glue. I'm sticking with MDF. I think old BBC designs like the Spendor BC1 used plywood which intentionally resonated to add bloom and colour to volcals. But that is really an added colouration and not part of the input signal. If in pursuit of accuracy you probably want inert cabinets from MDF, plenty of bracing and internal damping material. I bought some damping material from Vibraplast in Switzerland very similar to the No-Rez sold by GR-Research for lining buzzy cabinets. I lined my Linn Kabers, 5120 and 3 pairs of Tukans for my Atmos Home Cinema and will be adding some in my Keltiks when I do the Killer konversion.
 
You can get furniture grade Baltic Birch ply from Travis Perkins, I think its in 12mm or 24mm thickness, its a while since I got mine for a speaker build. I had to order in advance and they got it in, as it wasn't a stocked item. It was on the web site, took just under two weeks to get it. Good quality, very stable and dense lay up, no voids and good finish both sides.
The stuff B&Q sells is almost, but not quite, totally unlike plywood, to coin a phrase from Douglas Adams.
 
Helen Bach said:
Chipboard was the material used in the sixties/seventies. This was eventually replaced with mdf for a couple of reasons, including machine ability. Apart from ply, mdf seems to be expected, these days (even used as a selling point.. or not!). I have a pair of three-way 'speakers made of chipboard and closed box loading (from the '60's). Don't like mdf/reflex loaded, too much boom boom for me.
Click to expand...
Particle board persisted through the 80s & 90s. All my speakers of that era have had cabinets made of chipboard.

Peter Comeau is a big proponent of particle board for acoustic reasons. My Heybrook HB3 S2s from the 80s are made of quite thick particle board. I believe some of his recent designs for IAG have employed it.
 
You must log in or register to reply here.


advertisement


Back
Top