1 X 12 speaker enclosure design

[txbluesboy]

I wan't to come up with a speaker enclosure for an EV 12L that fits and looks right under a 26 ' wide head. My target size would be 26" wide 21" tall and 12" deep. I normally prefer open back cabs, but am wanting the best sound this speaker can give me. Should I go with a closed back, front ported design , maybe with tube ports? Anyone know any good links to study up on this? Thanks Terry

[iknowjohnny]

If you like open backs i wouldn't go with a closed, ported or not. I too prefer them, and a huge part of the sound is the sound from the back of the speaker combining with the sound out the front. And also the better spread instead of being so directional. Anything with a closed back will be much less diffused and create a more focused sound that you probably won't like if you are a open back guy.Possibly a partial back or some such thing, i dunno. But i'd make sure there is sound coming out the back to some degree if thats what you've preferred till now. I use a 12L in mine by the way and have for many years.

[txbluesboy]

Thanks, OK going open back, does the size of opening in the back correspond to the size of the enclosure or to the size of the speaker? I'm thinking probably both, but how do you determine it. I know it would be easy to copy a Matchless 1 X 12 or something else that sounds good, but Ireally would like a cab to fit the head.

[jaysg]

These things tend to be experimentally derived. Here is a Dumble and a THD. (both 2-12", but you can see how different they are)

[txbluesboy]

I guess I"ll just build the box and try different opening sizes. Not very scientific, but that probably suits my intellect better anyway.

[Phil_S]

It's probably worth reading up on the Golden Ratio. Google for it. Interesting stuff. Not sure just how important it is, but a good starting point.

[tubeswell]

I think open-backed cabs are better for geetar. Easy to tune as well if you start with a top board and bottom board at the back, at a ratio of about 2/3 board to 1/3 open, and then shimmy a little bit off one (or both) of those back boards until the boominess stops. That way it is easy to build it to the width and depth dimensions you want to match your head.

EVL 12" ported cab plans are attached FWIW

Also see:

http://www.duncanamps.com/technical/speaker_cab.html

[txbluesboy]

Hey Phil, Funny thing, I was thinking about how to determine the height and depth of the cab and something popped in my head I had read years ago about, what was it called golden measure---no, maybe golden triangle-- so I googled these phrases. The golden ratio, so I read up on it. Then I decided to check TAG to see if anyone had replied to my question and lo and behold you mention the golden ratio too. So thats what I'm trying first. 26" wide X 16" tall X 10" deep. Tubeswell, thanks for the 2/3 & 1/3 rule of thumb, I'll start there. Thanks for the duncan amps link I'll study that. I have already built a TL 806 cab and don't personally love it. Should I center the speaker or offset it some side to side (seems like I read something somewhere about offsetting the speaker to eliminate standing waves or something, anybody ever heard of this?) Terry

[Phil_S]

Well, don't put too much stock in any one thing. A while back, I was trying to build a 2-12 out of high quality 13mm birch ply. Silly me, I was thinking I could make dovetails with it. I bought it at a high end woodworking place, actually for a very reasonable price. I was the only one there at that particular moment on a Saturday morning. The guy in the shop cut the sheet for me. This wasn't Blowes or Home Despot -- the guy really knew how to use the saw and could make precision cuts. He even stacked up the boards and made them all identical in length and width and perfectly square. I hadn't thought through the project completely, so I had to whip up some dimensions on the spot. Anyhow, I didn't do so badly until I tried to make the dovetails and had all sorts of tearout. From there, I had to ruin the beautiful cuts I got at the shop and used a circular saw to reduce the length of the sides. I ended up with a pretty crummy cab, made with rabbets and some metal right angle hardware inside. I did a bad job on the baffle, too, and there was a 1" gap on one long side. I started out 2/3 open back, and it was poo. I cut a patch to close it, figuring my vent in the front would let out some air. In then end, it isn't particularly good looking, and even a little out of square. But it actually sounds OK. Essentially, a totally accidental cabinet. My only real regret is that I didn't to a very good job cutting holes for the 12" speakers and that made it very difficult to mount them. Otherwise, it was a great learning eperience. I expected to throw it away wnen I was done, but I decided it's a keeper. So, like I say, don't put too much stock in anything you read. Weird stuff can happen.

I'd tell you the dimensions, but it's on loan at the moment. I'd guess the sides are 12" deep, top about 16", and sides about 24". I had to angle the speakers to make them fit.

Good luck with your project.

[txbluesboy]

Thanks Phil, I figured out long ago I usually have to screw one up totally to learn how to do it right. I've already decided to forget the golden ratio and make the cab taller so I can make an extra baffle to try an Alnico 15" speaker

[Ken Moon]

Terry,

I built a nice big 1x12 cab, designed by Randy Fay of Phaez Amps, which is made for this type of speaker, and it sounds awesome.

The exterior dimensions are 20-1/2" x 27-1/2" x 11-1/4".

The interior dimensions are 19" x 26" x 8-1/2" IIRC, for a total volume of 2.3 cubic feet.

I put an Emi Delta Pro 12A in mine, but Randy has run his with the EVM12L, which he describes as aggressive and edgy, the Delta, which he describes as creamier and mellower, and his fave, the Emi DeltaLite 2512, a neo speaker, which has a slight high-mid/low-treble bump, like the much-loved Celestions. The cab has two front ports, 4 inches diameter x 3.2 inches long.

I have a couple of pics of the cab on my Photobucket page, under jaxmoons04 (it's a big black 1x12 with no grill cloth), but I can't access them from work

Randy has a couple of videos using this cab on YouTube, under his username, Ontariomaximus (you could also search for Phaez amp).

This cab was designed for a resonant freq of 71Hz IIRC - the details are in this thread on AX84:

http://ax84.com/bbs/dm.php?thread=370639

[txbluesboy]

Thanks for the info Ken! That is a big 1 X 12. That almost exactly the size of my 2 X 12 cabs. Maybe I will make a solid back and speaker baffle like you described and try it, it would be easy enough. Terry

[Ken Moon]

In case anyone's interested in this cab, here's a couple of pics - they're not the best photos, but you can see the overall size and shape, and the front ports:

[IMG767]http://i514.photobucket.com/albums/t346 ... 4/shop.jpg[/img]

[IMG761]http://i514.photobucket.com/albums/t346 ... mproom.jpg[/img]

[Structo]

Sweet Ampeg.

[Structo]

What is the gold panel amp on the left?
I can't make out the name.
Looks sort of like Meca?