DIY back loaded horn

[Andr039]

Hi, Lencoheaveners!
I doubted should I start this thread or not. The chance of fail is too high and I do not have enough time and skills to finish this project in reasonable time.
But LH community is so friendly and this is a good opportunity to get some experience scores even if the goal wasn't reached. 
So, here we go…
You may notice already – winter is coming (c).
Thinking what to fill my time up and hands I have checked my tract and realized that speakers are the weakest element of the whole chain.
Frankly speaking, it's rather entire weak, but my wallet is the weakest element no doubt otherwise I would just buy a couple of good
cabinets rather than spending my precious time with jigsaw and router (he-he, I do not believe it myself - hands need some job which
should be  differ from that with hand drill pattern).
Checking (reading mostly) about internet sound of different types of cabinets, neither more nor less than back loaded horns with full
range drivers attracted my attention. Man, I know how high I have put my goal, but as I could not listen them somewhere around
to check whether this was my sound or not, I have decided to build them.
Bought a router (180 bucks), new jigsaw (100 bucks)- the previous one passed away during deck building.
2 sheets of MDF (19mm), 4 of birch plywood (21mm) and 10 of plywood (3 mm) cost me 420 bucks.
Two Goodmans Axiette 8 inch drivers from Albion took away 240 bucks more.
plus router bids, jigsaw blades, some more screw clamps, glue and other little things..
Totally it already costs me near a grand. Hmm.. may be the idea of buying cabinets was not so bad, was it?
As I know nothing about two or more drivers' adjustment by filters, one full range driver per cabinet is my way.
However 8" axiette doesn't seem to fit well for my idea of BLH as its Qst is relatively high – 0.5 – 0.75 (data from i-net) for BLH. But I will try.
The project of BLH (model 3a) was taken from well-known in Russian segment of internet master, named Sergey 'Normann'.
See post #3 here:Audioportal.su

So, the idea is to get a nice couple of these (or similar): the picture was stolen from net



printed out the layout



got two huge sheets of rather thick MDF



i had to cut them before taken them inside of workshop



here the sheets are already a reasonable size



now i need to cut all that templates



i think it will take ages,
best,
Andrey

[pde2000]

hi Andrey, the goodmans axiette 8 was designed by ted Jordan (Jordan-watts), who has a website;  http://www.ejjordan.co.uk/ted/index.html

you will enjoy the new project.  no smelting lead?  need something to keep warm

[Rotsch]

here the sheets are already a reasonable size

 

.....reasonable size..... !!

Aha !! 

 

Good luck with your project !! 

[Andr039]

hi Andrey, the goodmans axiette 8 was designed by ted Jordan (Jordan-watts), who has a website;  http://www.ejjordan.co.uk/ted/index.html
you will enjoy the new project.  no smelting lead?  need something to keep warm

!! Thanks for link! sure, i will read it
no, (un)fortunately no any lead. i guess the cabinets will be heavy enough without lead. But i know some other things from Britain (Scotland, correct to say) which keeps me usually warm enough during this winter

.....reasonable size..... !!

Aha !! 

 

Good luck with your project !! 

Thanks, Roger, your good luck will support me when i'm cutting those 18 template!

best,
Andrey

[awty]

Great!

Look forwards to seeing the progress.

[Andr039]

Some progress
The router is for handy use only so it needs some improvements
I have cut a base and a window for that base in old chiffonier door



Now i may use it as a table router



here template from thin fibreboard is ready to be copied to MDF



first layer (and template for all next layers) is ready
just need to cut 27 more... and other parts too


Best,
Andrey

[gthang]

Nice work Andrey, i'll enjoy watching your progress.
I'm very impressed with your DIY router table, that's really good.

[ropie]

Exciting project, looking forward to seeing how it turns out.  

I've never used a router - do you cut all the pieces roughly and slightly oversized by hand with the jigsaw, then use the router to clean them all up to a precise shape?  Presumably the little chrome 'ferrule' on top of the router bit is what the template moves against?

[Wout]

Exciting project, looking forward to seeing how it turns out. 

Me too.
Andrey's build threads are among the best IMHO. 

[Andr039]

Hi, guys
thanks for your kind words!

do you cut all the pieces roughly and slightly oversized by hand with the jigsaw, then use the router to clean them all up to a precise shape?  

 
Exactly!

Presumably the little chrome 'ferrule' on top of the router bit is what the template moves against?

Correct!

Some more details:

As one layer of MDF will be used as a template for all the rest layers, i need to prevent this template from any mistakes.
in this particular case i want to save the size of the hole in its original 6 mm (ok, may be 6.5 mm) size
So i drilled three small holes in a washers and nailed them over the holes



these holes are used to fix template and lower layer tightly as you may see on the last pic.
(which is quite important for better work with router later)
Also I use these bolts as handles – it's easy to operate when cut by router



best,
Andrey

[rfgumby]

Excellent corners for the back wave in the BLH!   Great work so far.   

[Andr039]

Hey, guys
some progress update.



25 layers were cut by jigsaw and 8 of them (upper ones as you may see on the pic) were routed.
I knew that it was going to be a rather big speaker - i saw the size on the printed paper
but its damn colossal shape is appearing slightly already if compare with 8" driver.
a bit less than 49 cm is an upper width 
best,
Andrey

[David31]

A great project.  Reminds be a bit of building a boat with the templates and drawings etc.  (Based on my experience of watching my not-father-in-law build a clinker dinghy and occasionally holding the rove when the rivets were put in, by the way, and not from doing it myself!)

[Andr039]

Thanks, David

holding the rove when the rivets were put in

googled this part as i'm not so common with tool's names
is it correct picture?

Rove tool

[Rotsch]

Hey, guys
some progress update.



25 layers were cut by jigsaw and 8 of them (upper ones as you may see on the pic) were routed.
I knew that it was going to be a rather big speaker - i saw the size on the printed paper
but its damn colossal shape is appearing slightly already if compare with 8" driver.
a bit less than 49 cm is an upper width 
best,
Andrey

I do know it from the start !!
Looking at the first pictures...as you mentioned the "reasonable size "  !!! 
But a man has to do what a man has to do !! 

I think your effort will be rewarded !!
In dunno this speakers...nor have heard it....but...
1. Looking great (Although way too big for my liking...and flat    )
2. No one would ever even think about such a giant build,
    without gathering all the information to be prepared for work
    and know what it's worth...or what's promised !!

Have you thought about ...bending wood....??
I never tried it...but it's always fascinating me,
what could be done with it !!

I'll keep an eye on you, Andrey !!  =>