1x12" Cab Design Diary

[Happy Jack]

As a newcomer to this thread and with far too little spare time to read 550 posts on what is apparently a one-off design for a small bass speaker cab, can anyone offer a brief digest, ideally less than 3000 words?

[Phil Starr]

[quote name='Happy Jack' timestamp='1455016130' post='2974969']
As a newcomer to this thread and with far too little spare time to read 550 posts on what is apparently a one-off design for a small bass speaker cab, can anyone offer a brief digest, ideally less than 3000 words?


[/quote]Fair comment, but we've all had fun

That's what we're working on now, the hopefully final phase where we actually write up the design as a 'how to' guide with some pics and drawings.

[tauzero]

[quote name='Happy Jack' timestamp='1455016130' post='2974969']
As a newcomer to this thread and with far too little spare time to read 550 posts on what is apparently a one-off design for a small bass speaker cab, can anyone offer a brief digest, ideally less than 3000 words?


[/quote]

It's a one-off design for a small speaker cab. HTH.

If you start at page 14, you should be able to get the gist of what it sounds like and how it performs. Basically a 50l or so ported cab with a Beyma SM212 IIRC.

[Ghost_Bass]

I've got a first glance at the work in progress. This was made by Ian (Bottle), it looks great!

Let´s see if this link works. I'm not being able to post pics here. I use Picasa (now renamed to Google Photos) to host images and share the links with the "image" button but it's not working lately... maybe something changed in Picasa or BC... When posting i get a message saying "[color=#80001C][font=helvetica, arial, sans-serif][size=3]You are not allowed to use that image extension on this community."[/size][/font][/color]

So, hopefully here is the direct link to my Picasa account: [color=#212121][font=Roboto, RobotoDraft, Helvetica, Arial, sans-serif][url="https://goo.gl/photos/nWP1xKnVUeE9icK96"]https://goo.gl/photo...P1xKnVUeE9icK96[/url][/font][/color]

[color=#212121][font=Roboto, RobotoDraft, Helvetica, Arial, sans-serif]If it doesn't work heres another link for my dropbox: [/font][/color]https://www.dropbox.com/s/gnkn9urtt5r6u0w/1.jpg?dl=0


[color=#212121][font=Roboto, RobotoDraft, Helvetica, Arial, sans-serif]Let me know if you can open it.[/font][/color]

[color=#212121][font=Roboto, RobotoDraft, Helvetica, Arial, sans-serif]Cheers[/font][/color]

[MoonBassAlpha]

Links open fine. Nice one.

[Chienmortbb]

Opened both fine. Thank you for that. Will there be a cutting list?

[MoonBassAlpha]

I'm sure it was discussed at length earlier, but there's no internal bracing. Was it decided it was not necessary? I did read the whole thread, honest! It was a while ago though....

[Ghost_Bass]

[quote name='MoonBassAlpha' timestamp='1455578240' post='2980484']
I'm sure it was discussed at length earlier, but there's no internal bracing. Was it decided it was not necessary? I did read the whole thread, honest! It was a while ago though....
[/quote]

These plans are for a 18mm ply construction so i guess there's no need for bracing with this thickness.

[Phil Starr]

Hi all. the plan is to have a cutting list and a step by step guide.

The bracing will be drawn up later. I switched the design at the last minute. Mainly this was for two reasons; the slot ported cab was difficult to construct without a decent set of clamps and we found a significant resonance in the frequency response in the slot ported cab down to the speaker operating into a square section almost cubical space. In the end the tube ported cab was easier to build and since the whole idea was to make this as simple as possible I decided to go for the tube ported cab.

The unbraced panels in the 18mm cab vibrated a whole lot less than the braced panels in the 12mm cab. The bracing adds a layer of complexity and so I'm going for the 18mm cab with some minimal bracing. I haven't braced an 18mm cab so I want to try that before finalising the bracing. Copying the 12mm bracing would add too much to the weight and be over the top for what are inherently fairly rigid panels due to their relatively small size. Basically I didn't give any details of bracing to the guys doing the drawings but they can go in later.

I'll put enough into the write up for people to be able to build a slot ported cab or a 12mm cab if they prefer, it just won't be what I'd recommend.

In the meantime if you haven't already seen it I suggest you have a look at this thread, where Beer of the Bass has built a very similar cab with the Eminence 12A-2's in it. Well worth a look http://basschat.co.uk/topic/276469-a-pair-of-1x12-cabs/

[Beer of the Bass]

Cutting down the strips for bracing, working out their positions and getting it all fitted definitely added a fair chunk of time to my build, especially as I didn't have a table saw to cut long parallel strips with. With that in mind I could see the appeal of using 18mm ply with a simplified bracing scheme.

[Gottastopbuyinggear]

Having posted recently about pondering a 2x10 build and commenting I also fancied trying the Basschat 1x12, I thought with some holiday at Easter coming up I'd put my money where my mouth is and commit to the 1x12 build.

Feeling enthused and having ordered my 18mm Poplar ply I paid a quick visit to bluearan.co.uk where I find an availability figure of 5 to 7 weeks for the out of stock Beyma SM 212. Damn!

Anyone know of an alternative supplier?

[Phil Starr]

Always a problem with Beyma and i looked hard for a decent alternative for that reason in the end the specs and end result made me stick with Beyma, I had to wait 6 weeks myself.

The importers are LMC audio http://www.lmcaudio.co.uk/acatalog/LMC_Web_Catalogue_12__Drivers_53.html they don't have any SM212's in stock, but they are on order and Beyma are making a delivery 'before the end of the month' they are listed at £68.63 +VAT

[fleabag]

I must have got lucky when the gurus were helping me mod my two 2x10 cabs. I got my 4 Beyma SM110n's in much less time than that, depsite being special order from BA

[6v6]

+1 for lmc audio, I got mine delivered in only a few days. That was a year ago tho so I'd give them a call to confirm, they were helpful when I spoke with them.

[6v6]

Deleted duplicate post.

Edited March 18, 2016 by 6v6

[Gottastopbuyinggear]

Phil, can you give us a rough idea of what the bracing will be like for the 18mm cab? I notice you said that the unbraced 18mm cab vibrated less that the braced 12mm cab, so I'm wondering whether it's absolutely necessary to brace at all?

Following my post a few days ago I now have the Beyma driver on order, and I also have my plywood, so I'm eager to get going - I'll start a build thread when I do, as I don't want to hijack this thread, but hopefully at the moment I'm asking questions that other people might also have. Current plan is to build the basic box but not glue the baffle in straight away, so I can try different port lengths if I feel the need to experiment. I'm hoping that some gasket tape on the battens to which I'll screw the baffle will provide a good enough seal.

Anyone else got one (or more) of these in progress yet?

[Chienmortbb]

Once we have the design sorted and drawn with instructions, are we going to do a group buy on the drivers?

[Phil Starr]

I braced the rear panel, which is the biggest, with a couple of offcuts of the 3/4" ply glued along the longest length of the panel roughly 1/5th of the width in from each edge. This is the panel most likely to vibrate badly and the vane bracing just stiffens it up a little, it's fairly hard in such a small cab to brace it meaningfully front to back. I'm going to brace the side panels with a couple of broomhandle/dowels, just glued in place, again you could use off cuts of the ply, I have a lot of timber around so the dowel is to hand for me. There isn't too much flexibility in positioning the braces here either as they'll have to be clear of the speaker and the ports.

The whole point of the 3/4 (18mm) ply was to reduce the need for pracing and to keep it really simple. The unbraced panels are really fairly dead with the exception of the rear panel.

The material I use for a gasket to seal the baffle is the closed foam sold by all the DIY chains for sealing windows and doors against drafts. I always leave my baffles just screwed in place so I can get access to the inside should I need it, much easier than access through the speaker cutout.

Edited March 30, 2016 by Phil Starr

[Phil Starr]

[quote name='Chienmortbb' timestamp='1459352767' post='3015714']
Once we have the design sorted and drawn with instructions, are we going to do a group buy on the drivers?
[/quote]I suppose there is no harm in asking Blue Aran or LMC audio if there is enough interest.

Interestingly enough I've changed the amp I gig with from my Hartke 3500 to a LM Tube 500. I was using a 15" Deltalite with the Hartke but the Beyma sounds better with the LM Tube. I suppose that means I'm interested in a couple more myself.

Anyone else interested?

[6v6]

[quote name='Phil Starr' timestamp='1459370552' post='3015981']
Anyone else interested?
[/quote]

I'd probably be interested in one more so I can make a second cab

[Chienmortbb]

Beyma SM212 Group buy.

So far we have a total of

Chienmortbb X 1
Phil Starr X 2
6V6. X 1

Any more for anymore?

Edited March 31, 2016 by Chienmortbb

[Beer of the Bass]

Would a group buy save enough to be worthwhile? Looking at Blue Aran's quantity pricing, an order of 8 or more probably saves less than you would spend on posting the individual drivers out to everyone.
I'm still keeping the SM212 in mind as a possible option for my DIY cabs (which have Eminence Betas currently), but I'd want to spend some more time with the Betas before deciding if actually have a need to change. If I end up in a louder band some time, that might tip the balance...

[Phil Starr]

[quote name='Beer of the Bass' timestamp='1459420936' post='3016324']
I'm still keeping the SM212 in mind as a possible option for my DIY cabs (which have Eminence Betas currently), but I'd want to spend some more time with the Betas before deciding if actually have a need to change. If I end up in a louder band some time, that might tip the balance...
[/quote]

Honestly I don't think the SM212 would be an upgrade, just different. The efficiency is roughly the same. The SM212 has a better xmax so will handle deep bass at higher power before farting out but the Beta isn't bad at that. At the other end the Beta has a nicely shaped upper mid peak and the SM212 a flatter response and slightly better top but I'd be reluctant to call one 'better' in that respect, just different. The extra Xmax and the cast chassis of the SM212 edged it for me at the time but I'd happily see people use the Beta.

If curiosity overcomes you I suggest you try just one of the SM212's

[Beer of the Bass]

Yes, it looks like the extra output in the lows is the main advantage, and unless I find myself regularly pushing that limit it would likely be a sideways move. Though if anyone within a few miles builds one with the Beyma, it would be interesting to compare them side by side to hear that difference in voicing first-hand.

Edited March 31, 2016 by Beer of the Bass

[Phil Starr]

Maybe if I make it to the Festival this year!