Custom DIY 2x15 cab build
 

a few tb members asked that i start a thread on a cab that i'm currently building so here it is. it's not quite finished yet, so it's still a work in progress................

the goal:
1-a cab that will be capable of playing just about any gig (i.e handle alot of power and put out alot of volume)
2-it has to be fairly lightweight for its size (50lbs, or hopefully less)
3- i want it to appear like it's made out of 3/4" thick wood
4- i want the 'covering' to be somewhat soft and 'rubbery' and look like vinyl/tolex, but it shas to be lightweight to keep the cab light.
4-it has to fit in my car's (bmw 3 series) trunk

the materials:
1- 1/2" lightweight birch plywood (sides and back)
2- 3/4" lightweight birch plywood (baffle)
3- 3/4"X3/4" pine strip edging for the grill stand off
4- 1/4" pine strips (around the front edge)
5- two flared 4" ports
6- two Eminence Kappalite 3015's (non LF's)
7- 16 stainless steel 10-24 threaded inserts with 16 10-24 SS screws (speaker mounting)
8- one Neutrik speakon connector
9- eight small black metal corners (early Sunn type)
10- 4 large rubber feet (bottom) and 4 Fender sphinx glides 9side)
11- one Fender strap handle
12- 3/16" hole perforated aluminum grill
13- 8 grill rubber standoff supports w/screws and washers
14- herculiner rubberized truck bed liner (rolled on)
15- 1 can of SEM satin black vinyl spray paint
16- can of Krylon flat black spray paint (for the baffle
17- one mattress topper (for dampening)
18- Titebond II glue
19- PL premium glue
20- Black Felt (for the 3/4" grill standoff strips

the build:
i started by building the baffle. it measures 23.5" wide x 35" high x 3/4" thick:


i routed four areas on the back of the baffle to save a little weight, and made a rear panel the exact same size, only out of 1/2" ply. then i added bracing to it to keep it stiff. i also added a 1/2" piece for the speakon jack so i could inlay it flush on the back of the cab:



here's a pic of the cab with side sides and back all glued up, and the front baffle layed in place to check the fit. at this point the cab weighed 23 lbs:



the back panel showing the inlaid speakon connector layed in place:





this pic shows the front baffle glued in with the 1/4" trim pieces and 3/4" grill standoff pieces installed. i also made a twin brace out of some 1 1/4"x 3/4" pine to connect the baffle to the back panel. after that i layed the speakers in their 14" cutouts and installed the 16 stainless steel threaded inserts. the cab weighed 25 lbs at this point




being somewhat impatient i really wanted to hear this cab so i mounted the speakers and tested it. even without the dampening material is sounds really good and can go extremely loud without farting out. at this point the cab weighed 42 lbs.




i took it apart, sanded and prepped it for the herculiner. i found out that herculiner has some pretty large rubber chunks in it (that was way too bumpy for me), so after the first coat dried, i sanded them down quite a bit with my makita orbital sander. for the second coat, i strained the herculiner thru some wide gap cheesecloth to let only the small rubber particles thru, then i rolled the second coat on. it takes a good 24 hours to dry until it's no longer tacky, but it's starting to look like a tolexed cab, only more glossy:





tomorrow, i'm going to slightly scuff it and shoot it with some SEM satin black vinyl paint to get it's sheen the same as a tolexeded cab would be. the SEM stuff is super nice and it will etch and bond to the herculiner and can't scratch or peel off, so by thursday or friday i should be able to paint the baffle flat black, make the aluminum perf grill and paint and install it, along with the other hardware, the ports, the dampening and the speakers..........

this looks suspiciously like a deep Showman cab :ninja: :D

What's the depth, Vb, and Fb you're shooting for?

Nice build, btw :bassist:

Nice cab:bassist:

I was gonna say it looked like an old Kustom 215 before the black gunk. Make those port flares silver and cover it in tuck n roll, and it's deja vu all over again ! :D

True dat re Kustom 215 sans the tuck and roll. I just retrofitted a 2-15 Showman w/D140Fs but ported the cab and added some bracing exactly like this cab. I'm sure the extra Vb will be kind to the low end extension compared to mine, but so far I've no complaints :cool:

the cab's outer dims are 24.5"Wx36"Hx14"D, but since the speakers are front loaded the internal volume is 5.3 cu ft. i haven't cut the port tubes to length yet but in order to tune it to 45hz (which is where i think i want it) they should be 3.26" long. when i tested it, it was tuned to 42.85Hz since the ports are 3.9" long right now

what are your plans for the amp?

Looking forward to soundclips when this is ready :cool:

A sub 50lb 2x15. Very interesting. Look forward to hearing more.

i actually built it for my STM900 but it sounds great with my SVT too.

Johnk, this looks awesome!

This is slightly off-topic, but how do the tone of those 3015 non-LF speakers compare to old JBL's, if indeed they do? I know you have lots of experience with those speakers... what do you think?

Looks great John!

you'll have to tell us how much weight the bedliner stuff added.

Looks awsome!

thanks Zach.

IMO, the K140's have quite a bit better and more pleasing 'tone' than the 3015's. for me, JBL's just have this buttery, complex midrange and low end with a super pleasing high end that seems to 'caress' every note on the neck. the 3015's are much less complex and a bit 'stiffer' sounding, but can go much, much louder before they break up. keep in mind that i haven't broken in this pair yet and i'm actually thinking of replacing the paper dust caps on them with some aluminum JBL ones to give them a little more sparkle up top (which i did on my 2512 II's and i love them). if i were to compare the 3015's to a vintage speaker, i'd say that they're closer to sounding like an EV15B but with an EV15L's top end. i had a pair of Eminence 2515's in the past and i hated them. they had a huge midrange spike and sounded like cardboard compared to the 3015's.

looks killer! can't wait to see it finished!!

yeah, i'm very interested to find that out too. i'll weigh it tomorrow once it dries. the empty cab before the bedliner was 25lbs so i'll know exactly how much it added. i did put it on pretty thin but it covered it well and has a nice texture. it's actually about as thick as some of the thinnest tolexes, but without the backing cloth or glue.

BTW, i was originally going to go with a 16 gauge (.63") steel perf grill, but after seeing that they weigh a little over a pound per sq ft, i realized that it would add more than 6 lbs to the cab (13% of its total weight!), so i'm going with an aluminum one that will only add 3lbs, which is what the same sized 'conventional grill made out of wood and grill cloth weighs.

Excellent info--what's your source for the aluminum grill? Peace, Bob

Awesome John! Hey,We can just call you AJ from now on :D

i'm going to cut it myself (to save a little $) so i got a 36x40 sheet of it at mcmaster-carr (i'm picking it up tomorrow).


you can also get one cut to a custom size from online metals: Order Aluminum 3003 Perforated Sheet in Small Quantities at OnlineMetals.com