Easy 12" cab build

[funkle]

This looks a nice factor for small jazz gigs. 

I’m going to make one of Stevie’s larger flatpack cabs for bigger gigs, using the Faital 12PR320 with the compression driver. 

If I use this thread’s cab design with the 12PR320 driver, could I safely use the two cabs together if I ever needed ridiculous volume?...I doubt the need but you never know. 

The other question I have is whether I could squeeze a tweeter into this little cab. I’m too used to that extra top end. 

Edited April 6, 2019 by funkle

[Phil Starr]

Funnily enough I was loading up the small cab a couple of minutes ago and I wondered whether it would be possible to squeeze in a tweeter. I think that if I did try to do that I'd probably change the port into a slot port, alternatively you could easily shift the ports to the back. That would easily create enough space on the baffle for a tweeter. 

[funkle]

@Phil Starr I will PM you. 

[LukeFRC]

We need to have naming convention here...

 

 - like I think this is v1 basschat cab... 

v2 was Steve’s with a tweeter 

and v3 had the nicer horn and the faital driver.

 

so if you add a tweeter is that v1.1 or v4?

not sure what else you could name them after, Apple did big cats then Californian nature ... what is a bass players UK equivalent? 

[Chienmortbb]

This is difficult as during the past 6 years, many different iterations have been tried but but as far as I can remember (names are to be discussed). 

MK1- Tiger -single Beyma SM-212, four 64mm ports,  50Hz tuning, 50 litre cabinet volume. 

MK1.1  Tabby - As above but with two 64mm diameter ports and 30 litre cabinet volume. As built by Phil Starr at last year’s South West Bass Bash. 

Mk 1.2 Tortoiseshell. On the drawing board. Small improved 30 litre cab spec TBA. Phil is thinking about it.

MK 2.0 Lion - single Beyma SM-212, one 125mm port,  50 litre cabinet volume. Celestion CDX1-1415 neo compression driver P Audio Horn. This was at the shootout at the South West Bass Bash yesterday April 7th. 

MK 2.1 Leopard - Faital Pro PR320 12” + Celestion CDX1-1415 neo compression driver P Audio Horn mounted vertically. 50 🎂Litre cabinet volume. This was at the shootout at the South West Bass Bash yesterday April 7th. 

MK2.2 Snow Leopard - Faital Pro PR320 12” + Celestion CDX1-1415 neo compression driver P Audio Horn mounted vertically. Mounted inside a slightly taller CNC’d cabinet (30mm, 1.25” taller).

However work goes on so so we could run out of cats. 

Edited April 8, 2019 by Chienmortbb

[Chienmortbb]

For anyone thinking of building a cab without a tweeter, Stevie has designed a full ,size (50L) flat pack cabinet. You can just block the tweeter hole with a bit of wood and you have and excellent tweeterless 1x12. Click on the thing below to see the assembly.

 

Edited April 19, 2019 by Chienmortbb

[Johannes Bass]

Hi everybody!

I built Phil's cab last week the one with a single beyma driver that he built at the bass bash.

I had so much fun with building this and really like what came out! The gig I wanted to test it on got cancelled last minute but I wanna already post my experience her so far.

I mainly play double bass and do a lot of jazz gigs. The challenge is to find a setup thats portable but powerful enough and nice sounding. I got interested in this cab because its quite powerful and phil made this smaller version of the original design to have less boominess in difficult rooms. This is an issue I experience quite a lot with double bass.

So I got the parts and built it which was fun, building it yourself you also get to chose the color an little extras which makes it  truly yours.

From testing it at home and in a rehearsal without drums i can say that I'm really happy so far. I'm using it with a aguilar tone hammer 500. My first impression at home was that I had to dial down the mids quite a bit. But when I used my headway edb-2 preamp with it it sounded way more natural, so I thought the sound profile of the aguilar could be an issue with this cab.

In the rehearsal with saxophone and jazz guitar though I found the sound great without adding the preamp, it was clear and natural. The room was a lot bigger than my small practice room where I first tried it but probably having also the other instruments changes a lot what you hear in the end.

I'm looking forward to test it on the next gigs then I'll be able to tell more!

[stewblack]

You've made a beautiful job of that @Johannes Bass love the kick back hinge! 

[Phil Starr]

Thanks for posting this Johannes. I hope you really enjoy your new cab. I'm really interested in how it sounds with DB. It makes sense to me that a bigger cab with more deep bass would excite resonances in the body of a 'proper' bass. They certainly excite room resonances which can be an embarrassment when playing live and was the reason I designed this cab. I was rolling off the low bass and boosting upper bass at almost every gig anyway so it made sense to try something with that sound baked in. The upper end of the Beyma speaker is slightly unusual compared with a lot of 12's. It is unusually flat with well managed cone break up and goes a little bit higher than a lot of the alternatives. Most 12's have quite a big peak at around 1-2kHz and roll off at around 3KHz. The Beyma is flatter and rolls off at around 4KHz, it's only a few notes difference but you'd definitely hear a different mid quality. I wasn't sure whether you'd hear it as more mids as in higher frequency or less mids as in missing the normal unnatural peak of other speakers. "Clear and Natural" is encouraging. Of course with the small cabs bass roll off the mids would sound subjectively more prominent anyway.

I didn't design this cab for DB, it was for horrible sounding rooms, but it makes sense that in trying to tame one we might of stumbled on a solution for DB. if there are any DB players in Somerset/Devon/Dorset who fancy a try I'd be happy to lend them my cab.

Edited May 16, 2019 by Phil Starr

[Johannes Bass]

Thanks @stewblack! I just found a clip on trolly  from Adam hall that I'll try to add for even more portability!😍

[Johannes Bass]

@Phil Starr thank you so much for making the design available, it's awesome that you share it with the bass community for free!!!

I will post an update on the sound when I get to test it out live. The beyma is indeed a nice speaker I wasn't missing definition so I think it covers the double bass quite well without the need for a Tweeter!

[Johannes Bass]

Little update:

I recently had a jazz gig in trio with Pno and vocals and one in quartet with drums, guitar and saxophone.

I find the cab does a great job. I can get through in the band also with drums with no problems. I think it covers all the important bits in terms of sound without too much of a particular range. In my experience, too much low end often results in an undefined "wobble" and too much high end becomes nasal and doesn't sound natural anymore. I think the cab works really well for double bass. I would like to try it with an acoustic image amp at some point as the aguilar is already colouring the sound. 

[JvJazz83]

Hi!

I have been reading this, and the other  build-threads for 12" cabs with  great interest, and have a question.

Has anyone modeled the 30liter cab for other drivers? The Beyma sm212 seems hard to find here in Norway, and buying from abroad would be relatively expencive with postage and taxes involved.

Eminence or celestion elements seem to be more readily available.

PS. I have no knowlege of the Magic involved in designing a speaker, but I can follow an "IKEA" description when i have to, and this seems like a cool project for the long winter nights here up north.

[Stub Mandrel]

9 hours ago, JvJazz83 said:

Hi!

I have been reading this, and the other  build-threads for 12" cabs with  great interest, and have a question.

Has anyone modeled the 30liter cab for other drivers? The Beyma sm212 seems hard to find here in Norway, and buying from abroad would be relatively expencive with postage and taxes involved.

Eminence or celestion elements seem to be more readily available.

PS. I have no knowlege of the Magic involved in designing a speaker, but I can follow an "IKEA" description when i have to, and this seems like a cool project for the long winter nights here up north.

Here it is in WinISD, assuming 30l cab tuned to 56Hz (two 64mm ports  160mm long) and 150W.

The Beyma is the green line, the bottom line is an MCM 55-2982 a budget-ish driver available from CPC for about £50. The red line is an Eminence Beta 12. From these three the Beyma is probably going to have the best balance of top and bottom end. That resonance for the eminence might make it boomy.

[Phil Starr]

10 hours ago, JvJazz83 said:

Hi!

I have been reading this, and the other  build-threads for 12" cabs with  great interest, and have a question.

Has anyone modeled the 30liter cab for other drivers? The Beyma sm212 seems hard to find here in Norway, and buying from abroad would be relatively expencive with postage and taxes involved.

Eminence or celestion elements seem to be more readily available.

PS. I have no knowlege of the Magic involved in designing a speaker, but I can follow an "IKEA" description when i have to, and this seems like a cool project for the long winter nights here up north.

I haven't modelled this in the 30l cab, it will certainly work in the 50l cab and Eminence say it works in cabs over 36litres. You'd use the same construction technique and the dimensions in the other thread

. There you are the model is above (I took a break to cook for friends and Stub Mandrel has kindly modelled it for you in the meantime) and with the 30l cab you are getting a 4db peak at 140hz and the cab rolls off earlier than the Beyma. I think that's a little too much and the excursion is likely to reduce the power handling too. The Eminence also has a midrange peak so you will get a 'smiley face' response baked into the cab, build the 50l cab and it will all be better controlled. Alternatively you could try the Faital driver used in the Mk 2 cab in the 30l cab. that will work well I think.

[JvJazz83]

Thank you, both Stub Mandrel and Phill Starr! This, I could actually understand, I think... The tips on the Faital might be a way for me, or I'll suck it up and get a pair of sm212's from eBay, as I'm thinking of building a pair of I ever get around to it.

[Beer of the Bass]

The Beta 12 is working out nicely for me after a couple of years use, but my cabs are around 45 litres.  They do have a flattering voicing for the kind of bass sound I like, but I wonder if the bump they have in the midbass might tip over into sounding boomy if you went much smaller. 

[Stub Mandrel]

1 hour ago, Beer of the Bass said:

The Beta 12 is working out nicely for me after a couple of years use, but my cabs are around 45 litres.  They do have a flattering voicing for the kind of bass sound I like, but I wonder if the bump they have in the midbass might tip over into sounding boomy if you went much smaller. 

That's how I read it, the Beta 12 likes a decent sized cab. At 45 litres the curve is a lot flatter At 200L you can tune it get way down past 40Hz, about -6dB @31Hz .  Win ISD is a fun toy...

 

[Johannes Bass]

On 27/05/2019 at 09:44, JvJazz83 said:

Hi!

I have been reading this, and the other  build-threads for 12" cabs with  great interest, and have a question.

Has anyone modeled the 30liter cab for other drivers? The Beyma sm212 seems hard to find here in Norway, and buying from abroad would be relatively expencive with postage and taxes involved.

Eminence or celestion elements seem to be more readily available.

PS. I have no knowlege of the Magic involved in designing a speaker, but I can follow an "IKEA" description when i have to, and this seems like a cool project for the long winter nights here up north.

Hey man,

I bought my beyma and parts here: https://en.toutlehautparleur.com/

"Welcome to the biggest stock in the EU of speakers and linked DIY parts."

It's a French site and I think they deliver also to Norway. You can get a quote for the shipping cost!

Cheers

[Marvin]

Is there good and bad plywood regards construction of the cab?

[stevie]

On 06/04/2019 at 13:45, funkle said:

This looks a nice factor for small jazz gigs. 

I’m going to make one of Stevie’s larger flatpack cabs for bigger gigs, using the Faital 12PR320 with the compression driver. 

If I use this thread’s cab design with the 12PR320 driver, could I safely use the two cabs together if I ever needed ridiculous volume?...I doubt the need but you never know. 

The other question I have is whether I could squeeze a tweeter into this little cab. I’m too used to that extra top end. 

Only just noticed this - sorry Funkle.

I wouldn't use the Faital driver in Phil's small cab: it's too small. It'll sound boomy with no low bass - a bit like the red curve in Stub's simulations above. The Faital is more efficient than the Beyma, but the downside is that it needs a larger cab.

Edited July 27, 2019 by stevie

[stevie]

1 hour ago, Marvin said:

Is there good and bad plywood regards construction of the cab?

Definitely. It will make a difference to the sound. Scandinavian birch ply is considered the best for cabs and is well worth the extra. Don't skimp on the wood - you'll not save that much and you'll regret it in the end. I normally specify B/BB.

 

[Phil Starr]

12 hours ago, Marvin said:

Is there good and bad plywood regards construction of the cab?

There are different grades of plywood and at extremes would affect the cabs performance but most of what you are likely to see would be ok. Poplar ply is very lightweight but the cab being so small that makes less of a difference to the overall weight. Low mass panels need extra thought to bracing too. I used Baltic birch as the original cab was built out of offcuts from my workshop. It's fine but the wood had repairs to the surface where knots had been and wasn't highest quality. I suspect that in this case Baltic was actually Russian birch. It also didn't machine very well which made it splinter when cut. I've gone back to Wickes who sell a fairly high quality hardwood ply which cuts and finishes well. they used to sell a marine ply which was very high standard but last time I could only get 'exterior ply' which I was very happy with. B&Q sells similar and will cut it for you in the bigger stores.

Plywood is moderately complex to specify, the grading is for the surface plies with AA or N being the highest quality and other grades having blemishes. However the interior layers are more important for sound quality, you don' want voids where the knots have fallen out and denser woods generally sound better. Often you can see voids by looking along the cut edges which should be solid. The other factor is the glue or resin used to bind the plie,. you want this to be strong. Exterior grades and marine ply are waterproof.  https://decordezine.com/plywood-grades-explained

Birch is preferred for portable cabs as it is moderately light but is tough so it takes knocks well. Often only the outside layers are birch and the inside is poplar. 

I usually go for AB grade where one side is perfect. There are no guarantees but it usually means the inside layers are decent quality and I actually prefer hardwood plies to birch as it is easier to work.

Basically though don't worry, the stuff from the warehouses is generally ok. you could agonise over details and it would make only a little difference to the outcome.

[Chienmortbb]

I would agree Phil although some of the Chinese stuff at B&Q I have seen recently is poor quality. 

 

[Phil Starr]

16 minutes ago, Chienmortbb said:

I would agree Phil although some of the Chinese stuff at B&Q I have seen recently is poor quality. 

 

That is quite possible. most of the sheds change their suppliers and fail to offer consistency. Most of the staff have no idea what they are selling so asking for help doesn't work. Some things to look for

check for at least one good outer veneer with no knots or unfilled holes. Two smooth outer faces is a good sign

Check the board itself is entirely flat. 

Examine the cut edges for any voids, if there are any at the edge you can be sure there are more hidden in the middle. If the edge cuts cleanly that's a good sign.