my 1x15" bass cab

[black_labb]

ive nearly finished my 1x15 bass cab. its using a 16ohm 15"bass speaker from www.warehouseguitarspeakers.com . the cab is made from 18mm mdf, and has 18x18mm pieces of hardwood to support the corners. it is glued and screwed with butt joints. it is a ported design with a volume of aproximately 120L and has a tuning frequency of 43hz (give or take a hz).


ive been doing alot of work on this in the past couple of days. ive glued the whole thing together, rounded over the edges, ported the cab, found some material to use as acoustic wadding and installed it, picked up some black vinyl to cover the cab in and made a start on making the frame for the mesh on the front.

here is the cab with the mesh i will be using as the speaker grill (its shadecloth material, which i have climbed on numerous times in parks where it is strung over an area, so i know it will be quite strong) the colour of the shadecloth is a bit closer to tan than in the pic.


here is the cab after gluing down the main section of the cab. i glued the material with some pva glue that i wasnt going to use as i use titebond for my instrument builds. notice the channel along the back panel. this is where the piece of vinyl for the sides, top and bottom meet the vinyl for the rear panel. i will cut both pieces in the channel, and put some piping (tan chord actually) in the gap to hide the seam.


here is the front of the cab. i am gluing down the longer side edges and clamping them down with the longer sections of the mesh frame. the short sides have been glued and trimmed. you can see the ports (42-44 hz tuning, depending on the volume taken up by the speaker). you can also see the acoustic wadding, which is actually hobby fill (for making teddy bears). seemed to be the correct material, and feels about right. the acoustic wadding is held back by some flyscreen, because nothing else seemed to work too well.


here is the rear panel of the cab after trimming back the vinyl to the channel mentioned above. you can also see the seam where the main section of vinyl joins, this is the bottom of the cab. the flash seems to excentuate the seam and corner joins. the seam is actually exact along the majority of it, with a section of 50mm where it is aprox .5mm. the hole is for the jack.


here is the rear section of vinyl being glued


im really happy with how the cab is looking. the vinyl has been going on really easily, and i havent any bubbles. i was making this cab as a bit of a budget unit, and didnt expect it to look very good, but a cant see why it wouldnt hold its own next to any mass produced unit. i was actually considering covering the thing in duct tape of alternating colours to create a simple covering that was easy to do, but decided against it when i figured how much duct tape i would need, and the price of it. im glad i chose to go vinyl. it was 42$ australian for enough for 2 cabs of this size, with some left over for a head or 2. ill use whats left over for this cabs little brother.

when installing the ports, i use the baffle as part of the port. i cut the extra length needed by the port from 65mm pvc pipe, and epoxied it around a hole a bit smaller than the 65mm inner diameter. i then used my router with a guiding bearing to follow the pipes edge. this seemed to be an easy way to get the unit flush and of the correct length. also beat paying 40$ for the 70mm hole saw to fit the 69mm od.

shouldnt be long before i get the rear panel trimmed, chord/piping installed, mesh +frame installed and hardware reinstalled.

all i need to do is decide on what to do for handles. im thinking of getting some simple ones that stick out the side, but im a bit unsure exactly what i'll do. might leave it without for a while and see how it goes. im also unsure as to wether i will install corner protectors. ill see how it looks, and wether i can get ones of the correct radius easily.

[Paul P]

Nice ! Please post more pics when you're done.

Paul P

[black_labb]

Nice ! Please post more pics when you're done.

Paul P

thanks

i had a busy night working on the cab (which is when i posted the topic) and then didnt go to my lecture (is usually pretty useless for the suject, which is "design fundamentals" funnily enough) and worked on finishing the cab before i went in to uni for my evening session. i managed to get the thing finished and plugged it in quickly before running to catch (actually miss) my train. the chord/piping was done, and worked very well, as well as reinstalling the wheels and putting the jack in. i also made the mesh frame and covered it as tight as i could in the mesh. grillcloth is very tight in there but fits nicely. unly problem is i will probably need to rip to grill cloth to take it out, hopefully i wont have to make any adjustments, as the cloth took a while to put on the frame while keeping decent tension.

visually the cab is prettymuch flawless. the corners have folds in the same way as any cab without corners does. they are virtually perfect, but the flash picks up the sides of the vinyl material.

i didnt play the cab at loud levels, but it seemed to sound great, but only had around 20secs to try (and its too late now that im home again).

here are the finished pics. some of the pics show the vinyl with a coudy look on it, that was just where i had wiped a damp cloth on it and it hadn't dried for the photo. the vinyl is in perfect shape.











ive had that buzz you get from finishing something like this all afternoon, as its prettymuch flawless. i still cant believe it looks so professional.

[black_labb]

had a listen to the cab today, sounded great (not that i have ever played a decent bass rig though) had some nice low end and the highs seemed good too. ill get a better idea when i play it in a band situation (but thats only competing with one guitar thats mostly played slide).

for some specs, the speakers efficiency is 99db, and in the enclosure the f3 is 49hz, with the 40hz mark at -6.5db. thats just the readout from win isd, which should be pretty accurate.

[Paul P]

Nice job on the speaker. It looks pretty heavy to have to cart to gig
but I guess for nice bass that's a price you have to pay. Handles would
be nice if you're going to be moving it a lot. I just received my grill cloth
in the mail today so I'll be able to start building my own cabinet shortly
(1x12 guitar cab).

Paul P

[black_labb]

thanks paul. the things not that heavy for a bass cab. reguarding the size, its just a bit taller than the average 4x10, and probably around the same weight. i may put some handles on it, but im thinking about it, and ill see how it goes without handles when i bring it places. it has wheels which is nice for alot of the time.

im also considering making the second one into a cab of the same size (or similar, might adjust it for evonomising from a 900x2400mm piece of mdf). im thinking that incorperating the handles into edges and using the bracing as the handle (to not lose the strength of cutting it in half) might be an interesting idea. ill find something to do with the extra precut mdf (a third cab) if nessisary.

[black_labb]

oh, and what is the ax12 going to be? open backed or closed? how will you cover it? what speaker?

[Paul P]

oh, and what is the ax12 going to be? open backed or closed? how will you cover it? what speaker?

What little audio background I have has been entirely from the hi-fi side of
things so I've been having an interesting time trying to get used to the way
reproduction is viewed in the guitar world. Just like distortion in an amp is
something that is revered by guitar players, provided it's of a certain
agreeable kind, distortion from the speaker is also welcomed by many.

I have trouble undestanding why someone would want their baffle to be
thin so it can rattle and shake and the speaker to be open-backed so the
sound waves from the front and back of the speaker driver can get all
jumbled together. In contrast, you don't have any of these philosophical
problems with your bass speaker.

My plan is to build a cabinet that will have a stiff baffle and parts of the
back that can be removed or installed so I can experiment with different
configurations. I've always liked the idea of back-firing speakers since
I find they add a lot of space to the sound so I'm expecting to prefer some
sort of open back. I also want my speaker up off the floor so I'll be putting
it at the upper end of a three foot or so high cabinet and I'm going to tilt
the front back a bit so the sound doesn't stay around my knees. Reading
about beam blockers and ice-pick-in-your-head high ends makes me think
that I may be doing everything wrong but there's only one way to find out.

I plan to use up some hardwood I have lying around from a previous
cabinetmaking life, mostly yellow birch, so I'll probably leave it uncovered.
I'll be building a matching box for my amp to sit on top. The speaker is an
Eminence Red Fang. Again I'm going for clarity but I'm anxious to see if
I'm going to end up with too much of it.

Paul P

[black_labb]

as always, make sure to post pics and comments on the build.

[Steve Conner]

Hi guys,

If you have any experience in Hi-fi you'd probably do well to forget it straight away.

Guitar cabinets aren't sound reproducers, they're sound producers. A flat frequency response isn't relevant: you look for a pleasing frequency response instead. In this context, open-backed cabinets are sometimes nice because they add notches and cancellations that give some life to the tone. These cancellations vary with direction, which is what gives you that big 3-D sound all around the room. They don't reproduce much low bass, but that isn't required for many guitar tones anyway.

A lot of the theory isn't relevant, either. I heard that Celestion refuse to release Thiele-Small parameters for the Greenback, and I've always suspected the reason is that the speaker is so non-linear, they can't be measured! I read somewhere that Marshall never bothered to calculate anything when designing their famous 4x12 cabinets: they just used the smallest cabinet that they could fit four 12" speakers into. The result was a big response hump around 120Hz, which I guess is now accepted as the holy grail of tone!

About the thin, shakey baffle thing, I have a 5E3 clone and it sounds wicked. ("A trillion times better than a plugin" according to a local producer who worked on our forthcoming album.) But at the other end of the spectrum, you can have an EVM12L (an almost PA-like speaker whose T-S parameters are published) put it in a ported cabinet tuned according to the Thiele-Small math, and that sounds pretty wicked too. There really is no right or wrong, unless you actually blow the speaker, or end up with something so unwieldy that you never use it because you can't transport it to gigs.

For bass amps, it is a little different. Or is it? I remember hearing that the famous session bassist Carol Kaye used nothing but an open-backed Bassman. She did the Scooby-Doo theme tune as well as a lot of other things. Again, bass tone mostly comes from the lower midrange, and the actual bass content isn't as relevant as you'd think, especially on studio recordings that have to sound good on cheap radios and suchlike.

It's always nice to get some decent bass at a gig, though. But even then, how much fundamental bass does a SVT with a 8x10" produce? Does that 8x10" sealed cab really go down to the low B on a 5-string, or even the low E? And yet it's the holy grail of bass tone.

BTW, taking speakers up off the floor and tilting them back seems like a good idea. If the highs bother you, why not just turn down the treble on your amp.

[black_labb]

i know what you mean about the frequency response and the unstable baffle. im doing a 2x10 speaker cab for guitar (is 2x10 still called a cab, or is it an extension speaker or...) its going to be an open backed design and the baffle will only be connected to the top and bottom, and it wont even rest against anything in the other direction, which should almost make it like a sheet pulled tight when 2 people are folding it, and allow it to resonate like that. the idea is i still get the distinct sound from a tweedlike baffle mount, but avoid having anythign that the baffle can rattle against. this one wont be nearly as attractive as this build, as it will be a plain pine (or maybe a stain on it) pine cab to capture the real singing sound as people describe it by not "choking" the pine by covering it. i dont mind getting dings all over it, as it wont have started too pretty anyway.

for the bass cab i tried to get some decent low end response as it is something that is difficult to equalise into a sound (without alot of watts) in the speaker. kind of like how amps tend to leak the high end, speakers leak the lows (and the highs, but that isnt effected by the cab).