Single 12" bass Cab

[DIYjapan]

Hello My name is Brian and I am hoping to build a bass cab for myself over the next few months. I've only been playing the bass guitar for about 1 year but I really enjoy it more than guitar or piano. I bought a Hartke A35 combo when I started out and I have no complaints about that amp other than it isn't something to be used on stage for a live show. I recently bought a tc electronics bh250 head. I really like the sound of it so far through my headphones.
Where I live there are not any good options for checking out gear (Tokyo is 3 hours away - which isn't easy when you've got two little boys). So, I wanted to make my own bass cabinet. I've read through several wonderful threads on this site and talkbass. In particular there were some threads on here about a basschat 1x12 (which ran 21 glorious pages) and then mkII of that cab (7 pages) which really gave me some ideas to think on.

My goals are:
1) fairly portable, +-15kg
2) nice sounding (I'm not looking to recreate godlike bootsteps on the stage, just want a decent sound).
3) Not too expensive and a short parts list because everything is going to have to be shipped to my house.
4) Single speaker (heavily leaning towards the Eminence kappalite 3012HO)
5) Slightly Tall cab. In the future I plan to build a second 1x12 cube shaped cab to go on top of this one if it is necessary.
6) The final product if at all possible will have Grateful Dead Wall of Sound era Bag end cab ambiance (tall order, there)
7) Dimensions: (H x W x D) 610mm x 420mm x 390mm. This should give me a 67L ish cab.

Keeping all that in mind I came up with a few sketches. The woodworking end of it shouldn't be too difficult. It will but I've done woodworking and have friends here that can help me out with that aspect. What I CAN'T do is: the math to check if the box that I have come up with could/should be compatible with the Eminence speaker. If there is anyone here that can go over my sketches and give some advice.
In particular I'm concerned about the port width. I drew it in as 40mm (4cm) realizing that may need changing.
Also the length of the port shelf. In the sketch it is 250 mm.

Thanks for the read and for any advice you may have.
here are three sketches: 1, original idea 2, updated sketch, 3, close up of the box (baffle not shown)

[DIYjapan]

The images in the first post were fairly poor. Sorry about that. Here are some scans that are a little better I hope.

[Bill Fitzmaurice]

I see you're using spline braces on the box sides. Spline braces are better than no braces, but barely. Panel to panel braces are far more effective, and allow you to build a cab from 1/2"/12mm plywood for a lightweight cab. I also don't care for slot ports. Corner ports in all four corners work better, and they have the advantage of bracing the top, bottom, sides and baffle. As to the math, no one does math anymore. Download WinISD 0.7:
https://www.facebook.com/WinISD/posts/126113234166443

[markstuk]

Or you could build one of Bill's cabs.?

[funkle]

Build one of Bills cabs or a Fearful cab, would be my advice. Or the one of the 12" cabs being designed here by Stevie and Phil Starr... either the full range cab or the 'simple 1x12"' version. You've read the threads already...

Edited May 26, 2017 by funkle

[Balcro]

Downloaded that latest version of winISD from the facebook link and the home-page, but Norton Anti-Virus took umbrage with it on both occasions. Something called Heur.AdvML.C was identified and it was removed to the vault.

?

[Bill Fitzmaurice]

[quote name='Balcro' timestamp='1495818332' post='3306883']
Downloaded that latest version of winISD from the facebook link and the home-page, but Norton Anti-Virus took umbrage with it on both occasions. Something called Heur.AdvML.C was identified and it was removed to the vault.
[/quote]It's a Norton issue. See: https://community.norton.com/en/forums/heuradvmlb-detected-false-positive-or-not

I have Windows Defender, Super Anti Spyware and Malwarebytes, none have any issue with it.

[DIYjapan]

[quote name='Bill Fitzmaurice' timestamp='1495813099' post='3306832']
I see you're using spline braces on the box sides. Spline braces are better than no braces, but barely. Panel to panel braces are far more effective

Corner ports in all four corners work better, and they have the advantage of bracing the top, bottom, sides and baffle.

Download WinISD 0.7:
https://www.facebook.com/WinISD/posts/126113234166443
[/quote]

Thanks for the advice. I had no idea that spine braces weren't very strong. I will consider some cross bracing.

I'm not a big fan of round ports. I don't know why for sure. Maybe I'm just square. Was also considering making the cab sealed. I guess that would be simplest but, I've read that ported/vented cabs will have better more natural sound.

Last every one talks about winISD. I will try to download it. You'll have to forgive my ignorance here but what am I to look for while using the software? I am afraid that good results and bad results will look the same to me.

[Jack]

You can see the simulated response of the speaker cabinet. And using that you can fine tune the dimensions, port sizes etc to try and get the natural voice of the cab close to what you want. You can basically mess around until the graph looks like what you want: flat or not, low end roll off point, midrange peaks and troughs etc etc.

Last I looked there was a flash version of the software on their site, no download needed.

[Phil Starr]

The 3012HO is a bit wasted in a box that size. 35-40l is probably better. It will work in the Basschat 12 and you can change the shape to make it taller so long as you stick with the overall volume and the port dimensions. You could use the dimensions of the Mk 2 if you want and leave out the horn, Stevie spent some time working on the bracing and you could simply copy his. The Eminence Beta 12A-2 will work well in this cab. I can imagine getting hold of the Beyma we used would be nigh on impossible in Japan.

My son works in Tokyo

If you want help with the design just keep posting questions here.

[DIYjapan]

[quote name='Phil Starr' timestamp='1495879377' post='3307244']
The 3012HO is a bit wasted in a box that size. 35-40l is probably better. It will work in the Basschat 12 and you can change the shape to make it taller so long as you stick with the overall volume and the port dimensions.

You could use the dimensions of the Mk 2 if you want and leave out the horn, Stevie spent some time working on the bracing and you could simply copy his. The Eminence Beta 12A-2 will work well in this cab.

I can imagine getting hold of the Beyma we used would be nigh on impossible in Japan.

[/quote]

Wow thanks for this post. Using the Beta12A-2 would slash the overall price. Awesome. I may try to copy the Mk II. I didn't want to plagiarize so I was thinking to try my own way but if it'd be alright with everyone this would be the simplest route for me.

Later I may make the original 1x12 and sit it on top or underneath the mk II. Hmm, something to think about indeed.

I looked all over and that Beyma is not to be found here. Oh, well.

[DIYjapan]

If the Beyma is not available for the original 1x12 what would you suggest as a replacement? Eminence is the easiest to find but celestian is also available.
In the thread for that cab the 3012HO was considered but if that beta would work in both the original and MK IIs I'd be hard pressed to choose which to build first.

[Beer of the Bass]

Regarding the Bag End/Wall of Sound look, I got a similar sort of finish on a little 1x10" cab I built using birch plywood, stained brown then finished with Danish Oil and Briwax. If you did that and mounted the speaker with four metal L-clamps it should look about right.

[DIYjapan]

[quote name='Beer of the Bass' timestamp='1495883613' post='3307309']
Regarding the Bag End/Wall of Sound look, I got a similar sort of finish on a little 1x10" cab I built using birch plywood, stained brown then finished with Danish Oil and Briwax. If you did that and mounted the speaker with four metal L-clamps it should look about right.
[/quote]
Thanks for the tip. I was thinking of staining the finished cab brown then sanding it back a bit for a worn look followed by try-oil or Danish oil.

How did you apply the briwax? Any tips there?

[Beer of the Bass]

[quote name='DIYjapan' timestamp='1495885157' post='3307331']
Thanks for the tip. I was thinking of staining the finished cab brown then sanding it back a bit for a worn look followed by try-oil or Danish oil.

How did you apply the briwax? Any tips there?
[/quote]

It was a couple of years ago, but as far as I can remember I used a water-based stain, then let that dry for a couple of days, then a couple of coats of Danish Oil applied with a cloth, then Briwax applied with a Scotchbrite abrasive pad before buffing with a cloth.

[DIYjapan]

Beer of the bass that sounds great. I will give that a try but I'll have to use tru-oil because the Danish oil runs about $100 per can here.

[DIYjapan]

Question regarding downpipe ports.
I was hoping for a vented plan because it's all wood and glue and things I'm familiar with but most people on here are recommending tube ports. So my question is this: do they need to be supported by braces inside the cabinet or are they simply mounted in the baffle with glue?

[Bill Fitzmaurice]

[quote name='DIYjapan' timestamp='1495931610' post='3307648']
most people on here are recommending tube ports.
[/quote]I didn't. You may find these threads interesting, including the builder's choice of finish:
http://billfitzmaurice.info/forum/viewtopic.php?f=30&t=24323
http://billfitzmaurice.info/forum/viewtopic.php?f=13&t=24354

[DIYjapan]

actually I've started to come around to the tubes. Thanks for the previous links. I also saw a really nice 1x10 on an old thread from beer of the bass.
As for tube bracing anyone know if it's necessary or not?
I looked back at the basschat112 and Mk II threads those ports looked to be unsupported with inner bracing.

[Phil Starr]

You'll find designing cabs is a bit like wrestling a balloon. You force one problem into place and something pops out somewhere else. We've very much found that to be the case with designing the Basschat 12.

The main thing I was trying to achieve in the Mk1 was a decent speaker that would be easy to build. If you follow the original thread you'll see I built both a tube ported box and one with a wooden slot port. I plumped for the tube ports because of the simplicity of the build and the ready availability in Europe of black downpipe of the right diameter. We ended up with four to keep the port noises down.

The slot port version had a resonance when I dropped it, I couldn't leave it alone though and when I went back found it was down to a reflection off the port itself. I damped it down with some judicious stuffing and it could have been designed out with a taller narrower cab. Having built both I thought the tube port tube design was easier to make for someone with limited tools and woodworking experience.

Since then working on the Mk2 we've found that a single port gives a lot less port noise than a group of four with the same cross sectional area. I'm not keen on four corner ports for that reason, but it does help stiffen the cab. Balloon wrestling again.

My conclusion? I wouldn't worry too much about the ports. If you are a confident woodworker forming them out of wooden slots is fine. The four ports in the Mk1 have never made any audible noises at a gig, even when pushed hard, most/many manufacturers of bass cabs make slot ported designs and there are successful designs out there with corner ports.

[DIYjapan]

Looks like a 3 x 6 piece of 15mm ply will be sufficient for most of my cabinet.
I have found birch ply but it will run $150~200!
Searched the net and found Japanese Linden (basswood) at the same size for only $60 or so plus that site will cut the wood for me which is a major plus because all I have is a hand saw.
Question: anyone use linden for a cabinet before? Did you find it sturdy enough?

Edited May 30, 2017 by DIYjapan

[Phil Starr]

Whilst I don't know about basswood as a material for ply I would imagine it would be OK, a whole variety of plywoods are available here and often the only part of the plywood that is the named species are the face plies. One supplier over here offers a generic 'hardwood' ply which I prefer to birch ply anyway. Given the quality of Japan's carpentry and the use of a lot of indigenous semi-tropical timbers I wouldn't be surprised if it is very decent quality.

We designed the cabs so you could build two out of an eight by four sheet so 18sq ft should be plenty.

[Bill Fitzmaurice]

I don't know about Linden, but American Basswood is too lightweight for speaker cabinets. It's considered a junk wood, not suitable for construction or furniture. It doesn't even burn well.

[Thunderpaws]

[quote name='Phil Starr' timestamp='1495956179' post='3307691']

The slot port version had a resonance when I dropped it, I couldn't leave it alone though and when I went back found it was down to a reflection off the port itself. I damped it down with some judicious stuffing and it could have been designed out with a taller narrower cab. Having built both I thought the tube port tube design was easier to make for someone with limited tools and woodworking experience.

Since then working on the Mk2 we've found that a single port gives a lot less port noise than a group of four with the same cross sectional area. I'm not keen on four corner ports for that reason, but it does help stiffen the cab. Balloon wrestling again.

My conclusion? I wouldn't worry too much about the ports. If you are a confident woodworker forming them out of wooden slots is fine. The four ports in the Mk1 have never made any audible noises at a gig, even when pushed hard, most/many manufacturers of bass cabs make slot ported designs and there are successful designs out there with corner ports.
[/quote]

Is it the volume of the port that matters? For example, if corner triangular prisms were used, should the volume of the prism be the same as the volume of the cylinder that makes a circular tube port?

[Beer of the Bass]

[quote name='Thunderpaws' timestamp='1496179548' post='3309432']
Is it the volume of the port that matters? For example, if corner triangular prisms were used, should the volume of the prism be the same as the volume of the cylinder that makes a circular tube port?
[/quote]

Unfortunately, the relationship between port surface area and length for a given tuning frequency is a bit more complex than that, which is why most people use modelling software rather than working it out on paper. As the surface area increases, the length required increases too, so for example a 100mm diameter port needs to be longer than a 75mm diameter port would for the same tuning frequency.