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112 Speaker Cab thoughts?

12K views 126 replies 15 participants last post by  laristotle 
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#1 ·
I recently acquired a Celestion G12-80 Classic Lead to upgrade from my Weber Alnico 10.
At first, I was thinking of just cutting a bigger hole in the Baltic Birch baffle of the current
cab that I have (nothing special). I plan on selling the Weber. Then the thought of selling
the Weber in it's existing cab and either buying or building a 112 is making more sense.




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Wha 'cha all think?
 
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#2 ·
The Celestion's an upgrade over the Weber? :p

Tough call. There's both adv and disadv to selling the speaker with or without the cab. I'd offer it optionally with the cab to split the difference here/on kijiji and see what bait the fish prefer. That said, a no-name cab (DIY?) will never be worth much , so what's your time to build a replacement vs enlarging the hole cost you?
 
G
#3 ·
The Celestion's an upgrade over the Weber? :p
I needed (ok, wanted) an increase in handling power (80 vs 30 watts) and the price fit my budget.

That said, a no-name cab (DIY?) will never be worth much , so what's your time to build a replacement vs enlarging the hole cost you?
No rush, I'm in no hurry.

Enlarging the hole would be the most time efficient way of going.
Looking at some of the beautiful work done by forum members over the years has me wanting to build one too.
A little googlin' brought up this;
FORTE 3D 112 GUITAR SPEAKER CAB

 
#4 ·
I needed (ok, wanted) an increase in handling power (80 vs 30 watts) and the price fit my budget.



No rush, I'm in no hurry.

Enlarging the hole would be the most time efficient way of going.
Looking at some of the beautiful work done by forum members over the years has me wanting to build one too.
A little googlin' brought up this;
FORTE 3D 112 GUITAR SPEAKER CAB

Thanks laristotle for posting this, I'd never seen this cabinet before and to me it looks really interesting..

I'm interested enough that I'm going to make one for myself sometime soon.

This picture leaves few questions.

 
G
#6 ·
From the link that I provided previously

Weighing in at a modest 30 pounds, the cab is built with side ports and has an internal design that reflects the
sound that comes from the back of the speaker out through the sides. The result is some of the characteristics of
a closed back cabinet, nice low end punch and tightness, but the breathiness and volume projection of an open back.
 
#9 ·
Those are awfully big ports.
The surface area with both of them adds up such that it might as well be an open back.
Prolly be better if it was an open back.
At least an open back makes frequency cancelling less likely than side ports.
Unless there's some kind of oval tubing attached to increase air-flow path length.
Then again maybe they want frequency cancelling to occur in order to scoop a certain range to achieve a particular tone.
 
#11 ·
dig ding, what he ^ said (plus also weight reduction). Personally I am skeptical of the whole design for a number of reasons, but maybe it works. There's no way in hell that the routes dampen anything any more so than the unaltered panel would. Also this:

Those are awfully big ports.
Prolly be better if it was an open back.
At least an open back makes frequency cancelling less likely than side ports.
An open back also eliminates a lot of resonances and backwave distortion because the backwave goes straight out the rear vs bouncing around inside a bit first.
 
#12 ·
I don't know if its in your budget, but Mark Stephenson's FV cabinet is the best that I have ever used. Open-backed dynamics with closed back low-end. None of the placement issues inherent to open back. I have mine right beside a closed back cabinet and an open back amp hooked up to a route box, so I can A/B them on the fly with the same guitar. You truly get the best of both cab styles. Expensive, but well-designed and build quality second to none. Check his website.
 
#18 ·
Just so I understand what has been noted above, can someone please confirm i'm reading it right.

We're saying the uneven surfaces formed by the weight saving dado's (that if required could all be at different depths and have different widths), will neither dampen nor diffuse the sound waves coming at them, correct? Because if cut correctly they could display qualities of a wall meant to do just that.

We're also saying the reflecto panels (yes my term), if placed properly, will not deflect the sound out those side ports, correct? Because as above, if built and placed properly they would seem to display the qualities of panels in plenty of speaker cabinets that are meant to do just that, sometimes with a delay or other attributes.

Personally I think both those features would work as noted to some degree, I think the reason those cabinets are no longer for sale by that company is a result of doing far too much work by hand and having no sense for what the price point should be, not because the design has no merit.

So here's a proposal and I'll make it first to first Larry (because he posted the cab) and to Granny Gremlin (because he's a skeptic)

I will supply free of charge (you just pick up in Concord Ontario); all the components pictured above, in the same European 13 ply plywood the original maker used, plus whatever hardwood strips you need for cleats. They'll be completely cnc machined and 100% ready to assemble. We'll make the reflecto-baffles adjustable for angle so we can have some fun.

You guys; start a thread, assemble the boxes and put a speakers in them, play it and post your impressions.

If it works, cover the mother in tolex and have fun... if it doesn't, curse me and sell the speaker, and keep telling yourself - nothing ventured, nothing gained.

If you two guys are interested let me know, Jim.
 
#20 · (Edited)
We're saying the uneven surfaces formed by the weight saving dado's (that if required could all be at different depths and have different widths), will neither dampen nor diffuse the sound waves coming at them, correct? Because if cut correctly they could display qualities of a wall meant to do just that.
Will not dampen. Will not reflect (angle of incidence = angle of reflection). Will refract/diffuse. But not wide b/w diffusion because they gaps aren't varied in dimensions (so low Q or narrow range of frequencies being diffused).

Also, don't worry about delay. Sound travels at ~ 1000'/sec. So a 1 foot box would have a possible internal reflection delay of 2ms (there and back), well inside the Hass zone (where you start to hear sounds as separate events).

That's a great offer and I hope it happens. I'd be interested in the outcome. Those cabs are highly regarded in some circles.
 
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#19 · (Edited)
They won't dampen (unless u calculate properly and they become slot resonators... which only work at a given frequency), but could diffuse ( in a broadband sense even if you increased the size variation as you suggested).

That said, this would likely not be desirable as I touched on above.

It might sound awesome, but not for those reasons.

I would accept the proposal, but I'm gonna have to figure out if I can test it properly, and as to be objective.
 
#29 ·
TimeLine is a great concept - I'd love to try a guitar cab like that. Remember the DCM TimeWindow hi-fi speakers? Unique at the time. That was my first exposure to timeline technology.

But they tend to be large. Which can be a big disadvantage sometimes. I would think Thiele designs get 90% of the way there, sonically, with a much smaller footprint. My Thiele w/ EVM12-L is an amazing cab, although quite heavy with that driver (heavier than many 112 combos).

I have a 212 horizontal horn reflex cab that mean to put better speakers in and play around with. It's somewhere in the middle of that pile of 'things to do when I retire'. I better retire soon, before that pile falls over and kills me.
 
#33 ·
Think of this, but not as complex a pattern.



This is an RPG diffuser panel, from the brilliant mind of Dr. D ' Antonio.
Ok I'm ready to get on with the programming, I agree the grooves are a weight saving feature but I'm going to cut them just like that diffuser panel pictured above.

The idea being to diffuse or dampen the sound not being reflected out the ports... we'll see what it sounds like and worse case scenario the slots can be covered with fiberglass.

I'll post some screen shots in this thread of the parts as programmed before I cut them, if there's any more suggestions I'd appreciate hearing them, thanks.
 
#34 ·
Looks like they've been doing similar things in Europe.

Gear page has had a pretty good look at the Forte version.

Ok I've been working on my cnc program and the final details for the box, so a bit of an update.

Looking at the baffles I've decided to follow JBL's lead and use a curved deflector.

I've made the handle cut out and recessed jack plate cut out to dimensions found for those parts found at NextGenGuitars.

I'm using a large finger-joint detail for the corners of the box, they'll be pre-drilled for screws and along with glue will be quite strong.

Overall size is 21" wide x 16" high x 15" deep - I added an inch to the depth to make a bit more reflecto-room inside...

Here's some screen shots of the parts I've done the machining for -


The bottom with radius grooves for the baffles and dado's at different random depths to relieve weight and perhaps more;



The top with cut out for the handle;



The sides with reflecto-ports;



If you jam all the parts for 3 complete boxes into an optimizing program it dumps out two programs for two sheets of plywood, in about 8 seconds, that look like this;





I'll be cutting these parts in less than a week, if there's any suggestions fire away, signing out for the evening.
 
#36 · (Edited)
It's not something like the grooves increase the surface area or something like that?
Technically they do, slightly. Don't think that's relevant in a speaker cab, though the associated increase in volume would be (it's not a very significant increase in volume).

Looks like they've been doing similar things in Europe.

Gear page has had a pretty good look at the Forte version.

Ok I've been working on my cnc program and the final details for the box, so a bit of an update.

Looking at the baffles I've decided to follow JBL's lead and use a curved deflector.

I've made the handle cut out and recessed jack plate cut out to dimensions found for those parts found at NextGenGuitars.

I'm using a large finger-joint detail for the corners of the box, they'll be pre-drilled for screws and along with glue will be quite strong.

Overall size is 21" wide x 16" high x 15" deep - I added an inch to the depth to make a bit more reflecto-room inside...

Here's some screen shots of the parts I've done the machining for -


The bottom with radius grooves for the baffles and dado's at different random depths to relieve weight and perhaps more;



The top with cut out for the handle;



The sides with reflecto-ports;



If you jam all the parts for 3 complete boxes into an optimizing program it dumps out two programs for two sheets of plywood, in about 8 seconds, that look like this;





I'll be cutting these parts in less than a week, if there's any suggestions fire away, signing out for the evening.
From the review I'm thinking a lot of my suspicions about what's going on in this cab are about right.

The curved reflectors are a good idea, though if I might suggest they meet in the middle vs spaced as you have in the drawings (you have a bit of a void for standing waves there otherwise and it will pump the backwave out the sides better - more like the mouth of the horns on that JBL Paragon). Also, you have to make them out of something more substantial than the 1/8" masonite we saw the flat reflectors made out of in the pics up top. Not much (it's not dealing with any real bass), but some.

Doing that however creates a sealed pocket of air which is bad (it will resonate). You can relieve that by opening up the back wall of the cab behind the reflectors or at least venting it with multiple large holes (enuf so it doesn't resonate like a bass reflex).

A crude illustration (not to scale) to give you the idea (green = speaker; red the reflectors; black the exterior box; grey the ports).



You can make the top and bottom the full square footprint (vs following the reflector curve) for a) easier construction and b) so it is easier to stack. If you're worried about internal volume loss (yeah, maybe an issue), just make the cab a bit deeper to compensate. The side ports would be best as far towards the rear as possible (you need to leave some wood there for structural integrity).

This is starting to go a bit the way of a transmission line; the main thing missing is that the distance from rear of the cone to the port is not optimised in the same way - there will be some partial freq cancellation - the review above mentioned more mids; my guess is a bit less bass making it sound that way with more scatterred treble, while the mids get reinforced by the backwave without much cancellation in that region; kind of a bandpass transmision line idea.
 
#37 ·
Okay, here comes revision 1, curved baffles that extend to the center line, which makes perfect sense, as does extending the depth of the box.

My plan for the baffles themselves is two layers mahogany ply with a maple veneer between them, bent-laminated in a jig so they hold the radius and are stiff/strong/smooth - should be 5/16" total thickness.

Ports are to be placed as far back as possible.

I have an idea to overlap the baffles in the center leaving a space, this will be clear when you see the screen shot... as far as venting the space behind the baffles lets talk once you see my proposed plan.

Thank you for the input, Jim.
 
#38 ·
Ok mission accomplished.

I've increased the depth of the box to 16" and revised the baffles so they meet in the centre, where they'll be joined by a machined piece of hardwood.

The bottom gives you a good idea of the layout.



I've made one piece plywood rings to fit in the dado's at the front and back (that will hold the baffle and back door) instead of hardwood strips, here's the piece that will make the ring to hold the baffle with the adaptor ring (to run an optional 10" speaker) in the centre of the offcut or waste material.



I'm cutting on Friday morning this week and I'm open to suggestions until Thursday evening, thanks.
 
#40 ·
That's really shaping up nicely.

This bit below about the baffle mount, lends itself to an opportunity for an easy improvement:

I've made one piece plywood rings to fit in the dado's at the front and back (that will hold the baffle and back door) instead of hardwood strips, here's the piece that will make the ring to hold the baffle with the adaptor ring (to run an optional 10" speaker) in the centre of the offcut or waste material.

Since what you are doing is using a sub-baffle, you can float the baffle to significantly reduce the transfer of vibrations from the movement of the drive unit to the rest of the cab. I have done this on all of my DIY builds for a decade now; noticeable improvement in clarity. Most of the work is already done. Just instead of using mechanical fasteners to attach the baffle, you use adhesives with a constrained layer. 1/4" cork sheet is nice because you can just use wood glue (don't use too much; soaking thru the cork renders the exercise moot). There's also asphalt-based damping sheet (get at automotive audio places - to deaden the bodywork when you got stupid subs in the trunk) - one side has a decent adhesive. Or just use an adhesive that has some absorptive compliance to it; like Green Glue.

Just a thought.
 
#41 ·
Larry it is a cad program but it's one made specifically for the woodworking industry by a company called Planit Solutions, it's geared towards cabinets, furniture and fixtures, it's very user friendly and lighting fast, but you really pay for that.

It's hard to believe but I can tell you that the full software package allowing you to go from "screen to machine", with install and training cost in excess of $30K, plus there's a $1500 annual maintenance fee and an annual security key charge...
 
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