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Easy 12" cab build


Phil Starr

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I'm not sure how interested anyone will be in this cab but I'll offer it up for comments and questions in the hope that some of you might find it useful. At the recent South West Bass Bash I demonstrated just about the simplest way to self build a bass cab. I took 42 minutes from the first glue to a working cab, my aim was to demonstrate just how easy building your own cab can be. It was really just built for a demonstration and I didn't expect to use the cab much but it turned out better than I expected, so I thought I'd share the design.

 This cab is effectively the little brother of the cab I designed on here a couple or years ago, 14kg, 350W, 122dB and costing about£150 to build. You can find the information here https://www.basschat.co.uk/topic/227904-1x12-cab-design-diary

The original cab was a 50l cab based upon the Beyma SM212 driver and designed to produce lot's of deep well controlled bass with a neutral uncoloured response, several people here have built versions of the cab and I've been gigging it for two years. My problem with the original cab has been that in rooms with poor acoustics there has been too much bass and I was tending to dial down the deep bass and boost the upper bass. It sounds great in non resonant rooms and out of doors but has way too much bass if you are shoved into the corner of a low ceilinged room. Since I had promised to demonstrate a cab build anyway I thought I'd squeeze the Beyma into a smaller cab which would reduce it's bass output but give it a 2dB boost in the lower mids/upper bass which I thought would help cut through in difficult spaces. 

UPDATE It looks like Beyma are about to pull the SM212. Coincidentally I've just been given a Beyma 12CMV2 to try in this cab, it has the same magnet but with a heavier cone, stiffer suspension and a new voice coil. It also has a pressed steel chassis and is considerably cheaper. The good news is that in this cab it actually sounds better. The bass  response is basically unchanged, but one of the frequency anomalies of the SM212 has gone and there is a broad boost in output in the upper mids which makes the sound lighter and more detailed. I'm still investigating and haven't tried it at a gig for COVID reasons but I'm happy to recommend this speaker if anyone is thinking of a build. If I get more information I'll put it here.

If you do fancy building one yourself then the panels for the cab are 2x 374mmx290mm, 2 450mmx 290mm and 2 450mmx350mm (all 12mm ply) the front baffle is set back 30mm to allow for the grille so internally the cab is 350mmx450mmx236mm. the ports are made of drainpipe/downpipe which is 64mm internal diameter 160mm long You should be able to build it from these dimensions and the video. thanks to WoodinBlack for filming this. I loaned the cab to derreybass who has written a review, many thanks to him too. I'll save a space under for the review and put up some more pics when I get my upload problems sorted.

Thanks also to Mrs Scrumpy for lunch which is far too obvious in the video :)

 

 

Edited by Phil Starr
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Derrey's cab review

I borrowed Phil's quick build cab one Sunday afternoon as it turned out that he was practising at the venue I was to be playing in that evening with a worship band. Normally I play through a Barefaced Big Baby 2 and a Peavey Mini Mega 1000w amp. The hall in question is very lively accoustically and can very boomy and difficult at times to hear what is being played particularly on bass. Bearing in mind what Phil had in mind when he designed the cab I was quite intrigued as to how it would behave in the room in question. The Big Baby also has masses of low down response and massive volume when required. I started playing the first few numbers through my normal set up things were useable but a bit on the boomy side then I switched to Phil's cab for the final numbers it was quite noticeable how the sound was came through and was easier to hear as the small cab handled the mid range and higher bass without the muddiness. I think the design he set out to make worked very well and met the requirements he laid down. I did miss the real low down response of the Big Baby at times but it was easier to hear what was being played through Phil's cab in the very tricky conditions the hall presented. A couple of these small cabs would be very useable and a relatively cheap high quality set for any one. Highly recommended. Having seen him make it at the Bass Bash a quick answer as well. Well done Phil.

Edited by Phil Starr
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3 hours ago, prowla said:

Nice - I've been debating making a living-room friendly cab.

It does that job nicely it has a really full sound but without the wooliness you get sometimes in a small room. And of course it will keep up with a drum kit in the rehearsal room so you get both. My cab weighs in at just over 11kg but is an easy carry as much because of it's size and dimensions as it's weight.

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1 hour ago, Phil Starr said:

It does that job nicely it has a really full sound but without the wooliness you get sometimes in a small room. And of course it will keep up with a drum kit in the rehearsal room so you get both. My cab weighs in at just over 11kg but is an easy carry as much because of it's size and dimensions as it's weight.

Nice. 

I was thinking looks-wise too, something furniture-like. 

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30 minutes ago, prowla said:

Nice. 

I was thinking looks-wise too, something furniture-like. 

That's the advantage of a home build, you could build it out of a veneered board and have pretty much a furniture finish. 

Build two and put a glass top on and you'd have the worlds loudest coffee table :)

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The great thing about this cab is that it is not restricted to that one Beyma driver (nice though it is). Others will work too - although it would be sensible to check with Phil before using any old driver.....

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2 hours ago, Phil Starr said:

That's the advantage of a home build, you could build it out of a veneered board and have pretty much a furniture finish. 

Build two and put a glass top on and you'd have the worlds loudest coffee table :)

You read my mind!

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Interesting post, Phil, thanks.  You put that cab together about ten times as fast as I did either of mine!  I'd have liked to come over to that bash to say hello to you and the other guys driving the cab build diary, but unfortunately it was one of the few occasions that I had to be in work at the weekend. 

Looking forward to reading the review.

I'm still gigging two of the Mk 1 cabs, and understand what you mean about the amount of bass they produce, especially two of them together - I'm generally backed way off on the bass and pushing the mids a bit.  I really should try running one of them alone at a gig, but so far haven't as I can't help worrying that it might not be enough to compete with our drummer.

I didn't have time to go through the whole video last night (I've skipped through and watched about half), so apologies if I missed the relevant bit, but did you add any bracing to the cab, or do you feel that it needs any bracing?

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Try one, I've gigged a fair bit with one and had no problems, I'll admit the first time I took two cabs but just left one unplugged but it was all good. Thre's no bracing at present and the panels aren't too bad, being smaller they are intrinsically more rigid and the edge bracing of the battens helps as I said during the build. I'm going to run a signal sweep through them and look for any resonances that need treating and let people know.

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That's a great video! very useful! Hopefully it'll spur me on to actually make one for the banter. 

1. What type of glue did you use?

2. What's the dimensions for the center point of the speaker and ports? 

3. You showed a certain type of jigsaw blade, what was it?

4. For the rear wall, was it carpet or carpet underfelt? and the sides do you just recommend polyester quilt? 

5. Is the wiring self explanatory? ie instructions with the speaker. 

(I couldn't hear it very well due to poor computer speakers)

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The glue was PVA (white glue) from Lidl's pretty much any woodworking glue is going to be stronger than plywood so don't worry too much.

I'll measure up the speaker later, The speaker is on the centre line but spaced for the ports the ports are just kept away from the walls but the position isn't critical

The blade was one designed for curved cuts Bosch T101AO

There isn't any wadding at the moment, I'll experiment and let you know what works well.

It's just pin to plus sleeve to minus

sorry about the sound, I wasn't operating the camera which cut out about halfway through and lost the sound a bit after re starting. I forgot to press record on my Zoom

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12 minutes ago, Bigwan said:

Going to ask a ridiculous question... Would building this from 12mm MDF be madness. Have access to quite a lot of it... 

Not at all. MDF is dead/inert and quite heavy for its size and thickness. Probably worth adding some bracing internally. A lot of high priced hi-fi speaker cabs are made from it. Make sure you wear a dust mask when cutting it - some nasty stuff used to bind it together.

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4 hours ago, Marvin said:

What other drivers could be used in the smaller cab @Phil Starr?

And how would they effect the overall sound/tone?

I’m keen on building a cab to stick in my bands practice space and this looks ideal

 

 

 

I don't know at the moment in that I haven't modelled them, I'll try to have a look at a few of the readily available models and let you know.

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1 hour ago, Bigwan said:

Going to ask a ridiculous question... Would building this from 12mm MDF be madness. Have access to quite a lot of it... 

Dan is right, ply is used as it is quite tough and takes a lot of knocks which is important when you move it around a lot. It is also lighter than MDF. MDF is more consistent, less elastic and denser so is sonically better. The biggest problem is that it reacts badley to moisture. If it is going to sit in a rehearsal room it'll be fine. Id use it in preference for a hi fi design.

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With regards the adhesive I agree with Phil. When we were discussing the 50L MK2 cab I did some research on glue and the good old bog standard white PVA woodworking glue is as strong or stronger than all the fancy glues. The additives that go into the outdoor and waterproof varieties slightly weaken the bond but are still stronger than the wood.

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