A pair of speaker for under £30 ....

Top grade Birch ply does seem to be recommended. It has no caverties inside the ply and it is quite expensive. This is a good site for diy speakers and some very helpful members too.

http://www.diyaudio.com/forums/forumdisplay.php?forumid=22

 

Baltic birch ply is the best stuff- minimum of 5 ply. A very fine circular saw blade is needed to cut it cleanly unless you're veneering it as it tends to shred on the edge, even on up-cut blades. I was lucky to get a stack of it from a guy who restored vintage cars- they use it for dashboards, door trim etc.

The resonant properties are also supposed to be better than MDF. YMMV.

 

Yes, the first couple of sets will be mdf.

Cheers.

 

The talk of different woods is rather interesting subject on its own ...my suspicion is that mdf may be the best for this design ...as its need to be relatively dead.... as the standing wave in the unit needs to travel the sides need to shed any resonace quickly ...this is even more important in transmission lines and horns. I've look at the various properties of woods from oak which is stiff and dense ...and will ring like metal to pine which is soft and significantly less dense.

The pine I used was because it was cheap and I had no idea if the design was going to be worthwhile.

I'm looking to build a good set using particle board ...likely to be shelves from ikea ! again as they are cheap and well finished

I can get the sides in one material finish and the front back top and baffle in a complimentary finish ....cost will rise to about £60 for the materials but all I need to do is cut to length ...the edges should be good enough to give a nice airtight finish with a wisp of silicone. I may try to use the biscuit method of jointing too...any thoughts.

 

they look good.

I wouldn't use silicone if I were you, I heard it can ruin the voice coils ??
don't know how true it is?

use wood glue or decorators caulk.

on my speakers I used 18mm birch ply and 18mm mdf sandwiched glued and screwed they weigh a ton but they don't move at all

you could do a similar thing and use 9mm mdf over the top of the floor boards to get a nice finish and to stiffen them up a bit.

 

Top grade Birch ply is the most consistant through its depth as the layers are of almost equal density, where as mdf is compressed in one process so it ends up with a dense outer layer of aprox. 3mm to 5mm and then gets softer as it gets to the core.

 

but as I said ...it depends on the speaker .....

if its a ttl or horn the sound wave travels parallel to the plane of the wood not perpendicular as with reflex or sealed units ...in which case the actual wood plays no part in the final sound[ according to my research when I was building such speakers a few years ago]...

 

transmission line cook book of the top of my head ...but can't find the book at present ...to confirm

 

Are these the ones you were telling me about on Saturday Pete?

 

their the fellows......

and they still keep getting better as the cones break in !

 

I heard these little speakers today, and whilst Pete admittedly has a very nice front end, I was shocked to hear the beautiful sounds they are capable of - they are remarkable for the money...the bass isnt deep but nor is it lacking, it is clean and the vocals linger beautifully. there might have been a hint of brightness, but really, im splitting hairs. They are the sort of speaker you could listen to hour after hour. i was amazed to see such little boxes, that didnt look much, sound so good - have a listen if youre in notts.....

 

I'm so impressed that I'm going to build some nice cabinets for them at some stage.

 

So these are running full range, would using two or ore drivers per cab in a vertical array be worthwhile?

(I also have some of these, plus tweeters and 5" mid bass ones)

Steve

 

if I were to run more drivers I would mount one to the rear .....

pm if you want more info on the design I've used.

 

Speakers for under £30

I had the chance to listen to these at the weekend and could not believe how good these sounded even though the boxes were a little rough. As Pete said they have a different sound from the hi end speakers but sound is still unbelievable and well worth trying for yourselves. I am currently in the process of building a pair myself

Pete is well worth a chat with if you believe home made speakers or cables do make a difference....

Thanks again Pete

 

I always think that blind testing is a short sighted approach !

I had a chap over the other day ...he thought it was the statics playing not the tqwt's