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Topic: making a speaker cab, need help |
Chris Erbacher
From:
Sausalito, California, USA
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Posted 29 Jan 2006 1:11 am |
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| hey, i just got a 135 watt twin with two jbls, super heavy, so i'm going to keep the cab (you never know if later on you want to put the stuff back in), but make a head unit and a separate cab for the speakers, but i'm unsure about the cab design and specifics needed to achieve the best tone possible. does anyone know of a good site that has detailed plans of a tried and true 2x12 cab? or i'm wondering if it would be better to have two cabs, one for each speaker? any help is appreciated, thanks |
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David Wren
From:
Placerville, California, USA
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Posted 29 Jan 2006 5:28 am
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Don't know of any on-line references, but I did have a speaker cab made when I was a kid (yes they still had speakers then  ). It was for two 15s (for bass). The old guy that built the cab was real nice (used to recone speakers on S street, downtown Sac), and he explained every thing he did design wise. If you are going to enclose the cab, be sure to include some king of port in the facing board. He used a short 6" heavy cardboard tube in one corner, projecting about 4 inches into the cab. This is to capture the sound from the back of the speaker, and give more fullness of tonal specturm. I'm guessing but the samller the cab, probably the smaller the port (I've seen single 12 cabs with just a oval cutout below the speaker).
O
(===) well you get the idea...
Might also look at Peavey's site for dimensions of their speaker cabs.
Post some pics as you progress on this, and good luck.
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Dave Wren
'95Carter S12-E9/B6,7X7; Twin Session 500s; Hilton Pedal; Black Box www.ameechapman.com
[This message was edited by David Wren on 29 January 2006 at 05:30 AM.] [This message was edited by David Wren on 29 January 2006 at 05:31 AM.] [This message was edited by David Wren on 29 January 2006 at 05:31 AM.] |
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Jack Stoner
From:
Kansas City, MO
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Posted 29 Jan 2006 6:09 am
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I have two custom built 12" speaker enclosures that I'm using with my rack system. They were basically a copy of the old Peavey Nashville 112E speaker cabinets, like Jeff Newman used, except I used front mounting and different speaker baffles.
If you want info on them, e-mail me.
There is a picture of them on my web site.
http://web.tampabay.rr.com/jstoner1/eq.htm |
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David Spangler
From:
Kerrville, TX USA
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Posted 29 Jan 2006 10:28 am
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If you want to do it scientifically, there is a free program for designing ported cabs at: http://www.linearteam.dk/default.aspx?download=winisd
I have used this program with great results. You can come up with the desired dimensions of the cab and use the program to suggest port dimensions.
You could buy an empty Fenderesque 212 cab from http://www.avatarspeakers.com/ with the open back (actually an oval-shaped hole), add a plywood panel to cover the oval hole on the inside. Then cut a couple 3" holes and use 2-7/8" ports available from www.partsexpress.com to tune the cabinet per the software.
I'd be happy to help if you want to contact me.
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David Spangler |
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Richard Sinkler
From:
aka: Rusty Strings -- Missoula, Montana
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Posted 29 Jan 2006 7:10 pm
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At one time, JBL sold a kit with plans for different types of cabinets with port dimensions for their speakers. Don't know if they still do, but it would be worth checking into. I had one back in the 70's when I split my Twin and also made a single 15 cabinet.
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Carter D10 9p/9k, NV400, Korg Triton Le88 Synth, Korg CX-3 organ, Yamaha Motif Rack Module, Regal Dobro, Tele, Gretsch Acoustic.
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David Doggett
From:
Bawl'mer, MD (formerly of MS, Nawluns, Gnashville, Knocksville, Lost Angeles, Bahsten. and Philly)
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Posted 29 Jan 2006 9:01 pm
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| Chris, precise tuning of the cabinet volume and port is not as important for steel or guitar as it is for a bass cab or a full-range hifi or PA cab. These latter have to be precisely tuned to both reinforce where the speaker lows begin to drop off, without creating any resonance that overemphasises any particular note. You wont be playing any notes down that far. Just look at the wide range of sizes of 2x12 guitar amps and cabs. Anything in that range will probably work fine. You don't need the really big tuned cabinets that a bass would need. For example, Marrs makes the same small cabinet for use with either a single 12 or single 15. It's nowhere near as big as a tuned bass 1x15 cab, but it works fine for steel or guitar. If you can find plans for a cab the size you want, fine; but if not, just copy the dimensions of the typical 2x12 guitar speaker cabs being sold, and you should have something that works pretty good. A nice feature to have is a sliding panel in the back, so you can use it either as an openback or closedback cabinet. [This message was edited by David Doggett on 29 January 2006 at 09:02 PM.] |
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Chris Erbacher
From:
Sausalito, California, USA
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Posted 29 Jan 2006 11:00 pm
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| i think i want it to be open back, that way i get the sound coming off the back wall and also so the drummer can hear what i'm doing, he tends to play off of what i do since he has figured out primarily where my parts coincide with his playing rhythmically, so i guess it is a matter of copying the cab already there and doing it that way. i'm wondering if wood choice will affect the overally quality of the sound mainly in regards to baffle thickness and type of wood. i do like the idea of a slider if i do go with a port, but i'm thinking a box about the size of a twin cab with finger joints and a board that can be removed to expose the speakers, and one that can be removed to give it the open back, both of which would be held in place when in transport by buckles like a case has. this way, it is rugged and i don't have to worry about damaging the speakers. i kind of like the idea of not having grill cloth when the front cover is off, that way there is nothing to impede with any of the high frequencies, just pure tone. garcia had a cab like this, called a hard trucker cab, but a broun soun doesn't post any dimensions or plans on their site, so i guess i'll have to wing it. does anyone know where to get the little clamps that hold the speaker in, rather than having screws to hold it in? i like seeing the whole speaker front rather than just the cone, and having it done this way prevents the chance that a slip up could cause the screws to go thru the cone, you just lay the cab on it's back, place the cone where you want it and screw the clamps in place. |
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Ben Jones
From:
Seattle, Washington, USA
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Posted 30 Jan 2006 7:05 am
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"i kind of like the idea of not having grill cloth when the front cover is off, that way there is nothing to impede with any of the high frequencies, just pure tone"
-never heard of speaker cloth impeeding tone. front "cover" sounds like a hassle and extra weight. Maybe the expanded metal grill is what you want?
My thinking is that by the time i bought wood tolex, etc and removed the splinters and glue from my arms I could have bought a new empty cab from Avatar for less $. But sometimes its fun to just DIY. Good luck. |
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T. C. Furlong
From:
Lake County, Illinois, USA
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Posted 30 Jan 2006 8:11 am
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Once again, I agree with David Doggett. The tuning of the low frequencies in a cabinet is not that inportant with steel. What is important is that you like the sound of the cabinet. I have been spending a lot of time building, comparing (live and in the studio), and measuring cabinets for steel. One thing that I have discovered is that a closed back cab is not that much quieter behind it than an open back. The level is only lower in the high frequencies. Mids and lows either radiate through the back or go around the sides so there is a fair amount of sound behind a closed back cabinet. I know a lot of guys like the open back cabinets, but man a single 12" closed back sure sounds good to me. Also, my favorite guitar cabinet is a Marshall 2-12" closed back. Really responsive and tight. The materials in a cabinet will affect the sound but very slightly. The baffle board and the back of a closed back should be as rigid as possible. Like void-free Baltic or Finnish birch plywood. The sides aren't as important but a lot of builders use pine. I figure, why not it's easy to machine.
TC |
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Larry Clark
From:
Herndon, VA.
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Posted 30 Jan 2006 8:40 am
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Here's a link to JBL plans from their enclosure kit. There are plans for both cabinet and baffle boards for a 2-12 K120 box. Also check out the enclosure manual elsewhere on the sight for construction how-to's. http://www.lansingheritage.org/html/jbl/plans/1970s-kit.htm
refer to pages 10 and 12. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 30 Jan 2006 8:51 am
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Most good grille cloth is "acoustically transparent". That means it doesn't affect the volume or tone of the speakers. Having bare (exposed) speaker cones is not a good idea, as it only take an errant plug or other small object to puncture the cone, or dent the dust-cap. If it's the "look" you're concerned with, bear in mind that reconing speakers is an expensive affair after awhile.
Also, as the size of the baffle in an open cabinet increases, so does the bass response, to a small extent. Big cabinets just seem to sound fuller and "fatter" than smaller ones.
Been there, done that. |
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Chris Erbacher
From:
Sausalito, California, USA
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Posted 30 Jan 2006 1:25 pm
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| thanks a lot for the info, big help. i love this place... |
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