"Anahita" speaker project

[Arash]

I'm submitting this thread as a construction timeline of a speaker I'm working on. I'll add some photos and description. thanks for looking.

 

 

Parts: BMS 4592ND(mid and coax),Beyma CP-25, 15" woofer

Tools: router, CNC router, table saw, band saw, sander, nail gun, air press, vacuum bag press, clamps,...

Acoustic Measurement tools: Audiomatica Clio, Arta and Rew with Dayton mic

Material: Finland BB plywood, urethane glue, wood veneer

 

 

"Anahita" is the name of "goddess of water and fertility" in Persian mythology and the name of an ancient masonry edifice "Anahita Temple".

Anahita @ Wikipedia

Anahita Temple @ Wikipedia

Edited December 7, 2014 by Arash

[Arash]

as you have probably seen in the other thread, the speaker is a LS-inspired folded horn but curved sides and a totally different dog-house.

 

 

[Arash]

at first place we tried to laminating 3/8" plywood on a mold under the vacuum bag to shape the curved panels we needed but it's a very time-consuming (wasting!) job and we also faced the fact that putting layers on each other wont give an exact curve geometrically so I decided to use a CNC router to cut slices:

 

 

5H round steel-cobalt bares are used as dowel pins to reduce assembly error and increase the rigidity of the structure:

 

 

 

building the mid-range horn was done some other days, you can check details here

 

Edited December 7, 2014 by Arash

[Arash]

after countless of hours drawing and CNC working, the slices are ready to go to next level:

 

 

 

[Arash]

it's like a broken mirror jig-saw puzzle. as you put it together you'll find yourself shifting with it!

 

top section preview (no glue yet):

 

 

 

checking if the horn will fit in there. there is only room for two layers of grill fabric:

 

 

 

 

[Arash]

for now my biggest concern is about veneering the speaker at last. I never veneered a curved shaped part and we don't have a "polyurethane" vacuum bag which is capable of stretching 6x of it's original size. unfortunately we don't have the polyurethane bags here, I think I should buy some from US and make a new vacuum table for it. 

 

our veneer supply :

Edited December 7, 2014 by Arash

[Arash]

the bassbin uses a very high quality (expensive!) 15" woofer with cast frame and ND magnet with very flat frequency response. this is the measurement on a 47" x 47" open baffle. I have also CW1526C, Beyma 15LX60V2, Beyma SM-115K and some other woofers from B&C and BMS, I'll check them all in the bassbin and take a measurement and report back in case any case anybody is interested in seeing how other woofers perform in there. I think it's interesting to see how CW1526C will do here.

 

Edited December 7, 2014 by Arash

[Arash]

Top section parts that are 3/4" thick, two layers of veneers will add some thickness latter:

 

 

I put them on a cart to use in due time:

 

[Arash]

time to glue slices to each other:

 

 

we have 7-8 different types of nail and stapler guns but for this part of the job I used the biggest nail gun. this thing is very heavy and the nails are very heavy duty:

 

 

there is a thin layer of urethane on the nails that will melt down due to the heat produced while impact. it's literally impossible to take this kind of nail out of wood after pulling trigger so I have to be extra careful:

 

Edited December 8, 2014 by Arash

[Arash]

I use polyurethane glue between layers:

 

 

I use nine nails at each slice. I clamp each section so the glue extrudes out and then I nail them. they will stay under pressure to dry out. every side wall consists 41 slices so whole the wall will have 369 nails and I have to change the clamp position five time per slice so a total clamping of about 200 times! Oh my! I hope I can hold spoon for dinner:

 

 

 

 

[Arash]

a complete side wall. I put it ~20 hours to dry now it's time to clean the glue puff:

 

 

 

 

and I cut myself!

 

 

leaving my DNA sample on the speaker! maybe someone can manage an embryonic cloning so hopfully there will be more audio-crazy guys like me to build similar speaker!

 

[Arash]

pressing two layer of 1/2" plywood under press to get a 1" to be used as bass-bin top and floor parts:

 

 

[Arash]

time to sand the walls. due to the curve shape of it, vibrating or rotating sanding machine won't work here. they will probably ruin the part. I have to sand it by hand. I used some kind of spongy sander that adopts it's shape to the part. on the flatter part it stays flat:

 

 

on the curved surface it sit also well:

 

 

I used 80, 100, 120, 150 and 200 grit paper and the final result is very promising. I couldn't be happier:

 

 

 

 

 

 

[Arash]

just playing Lego to see how it looks like, nothing is glued yet:

 

 

 

 

 

[NBPK402]

AWESOME!

[Rudy81]

after countless of hours drawing and CNC working, the slices are ready to go to next level:

 

f401844fe0d70fe94cc387259375f40167e411c9414fedb87e940e294c4ac31c.jpg

 

509d0c05dc1bb6c3a45105f9d25eee65abe8bd7348407134889127e77f38589f.jpg

 

0cfe4ace0709e28e84803dfc8919a2b4f385d02861fa7651caf1bf5439f24fa5.jpg

 

Wow!  I want one of those machines!

[Rudy81]

Very nice sir!  Can't wait to see the final product! 

[Rudy81]

Arash, Looking at your pictures brings back memories of my attempt to hand build a center horn based on the Oris curve.

 

Lots of work as you well know.  

 

In my case, it was a huge waste of time and some good 18mm baltic birch.  The horn looked nice, but sounded terrible for a center channel. I'm sure my 'design' was very flawed.

Edited December 9, 2014 by Rudy81

[muel]

Wow!  Very nice! 

I'd consider going without veneer on the sides.   I think the curved walls could look wonderful if you are able to clean them up enough.  All the layers of ply might look pretty good exposed!

 

https://img1.etsystatic.com/000/0/6692015/il_fullxfull.312329085.jpg

[DizRotus]

Amazing work Arash.  I'm eager to see more.