DIY guitar cab

[BigRedX]

Guitar and Bass magazine ran a couple of articles about building your own guitar speaker cab earlier this year. I suggest you track them down.

[synaesthesia]

Guitar cab speakers are not flat to begin with, PA speakers are flatter generally in response; your typical guitar speaker such as a generic Celestion 12 or Eminence 12"(e.g lil texas etc) have spikes and ravines in response to begin with. For a flat modelling speaker, use a PA cab and use the digital device's cab sims. If those are crap, there is nothing you can do there, some devices offer customisable adjustments, most don't. Otherwise use a guitar cab, and turn off any speaker simulation if your device has that capability. If you are using a regular guitar head, then you have no real worries, except that you need to know that the choice of driver does make a lot of difference.

Cab tuning is unimportant if you are making an open back one, but if you are making a closed back one you'd want to know how you might be humping up the mid bass, if that matters to you. I have several cabs built for various purposes: my main pair of 1X12s uses PA speakers in a ported configuration so I can have a deep low end,which I can filter off as I like electronically. I also have guitar cabs built with Eminence Lil Texas, Tonkerlite and Celestion Gt12 -75s for different responses with built in spikes and ravines. The spikes are in the 1.8 Khz - 2.2 Khz zone, the zone that is 'nasal'; and the dip is typically in the 1.2khz - 1.8Khz zone.The difference is about 15 - 20db in the extremes. These are the typical responses of guitar drivers used by Fender, Vox, Marshall etc....They all drop off about 3.5 Khz or so some higher than others, but they all drop off at 150Hz or so and some low end performance can be improved by your box design, i.e. if you want to have thick fender 4X10 or Marshall 4 X 12 lows in a 1X 12 box, or if you play in a metal band and want a guitar 'subwoofer' tone, which really only goes to about 100hz.

Your metal grille source is here:
[url="http://www.speakergrills.co.uk/"]http://www.speakergrills.co.uk/[/url]

There are lots of fabric sources for a Fenderish, Voxy or Ampegish look, but I use french cane or rattan webbing (wicker grille) like Mesa Boogie in my own guitar cabs. The supplier used to be in Lincolnshire when I bought from them but they are now in Aberdeen somewhere.

[url="http://www.canestore.co.uk/sheetcane.htm"]http://www.canestore.co.uk/sheetcane.htm[/url]

You have to soak the rattan in water (soak for a day or two, not dip), and fix it on while it is wet, when it dries, it pulls back naturally and you will have a taut grille.

With regards to your original drawing, keep the box vertical as 2 X 12 but reduce the distance between the two drivers from 54.3 to as close as physically possible.

good luck.

Edited July 4, 2010 by synaesthesia

[skankdelvar]

[quote name='JackLondon' post='885386' date='Jul 4 2010, 12:17 PM']3. I will do a open back so do I use any sort of foam lining inside the cab or is it pointless ? Also is it a good idea to attach the grill to the back where the gap is to protect the speakers from possible damage etc ?[/quote]
Foam? No point. Don't put a grille on the back. You'll find it gets in the way when you want to put your leads, pedals, sandwiches, stash etc in there for easy transportation.

[quote name='JackLondon' post='885386' date='Jul 4 2010, 12:17 PM']4. Birch Ply is apparently the best but what thickness ? Is 12mm enough or should I go for 15mm?[/quote]
Myself, I've used 15mm and 12mm. Opinion varies on this one, so I'm keeping out of it.

[quote name='JackLondon' post='885386' date='Jul 4 2010, 12:17 PM']5. Is it possible to wire some sort of a switch into the cab to swap between the speakers being wired in series or parrallel ? To have the option of either 4 or 8 Ohm ?[/quote]
Given you've said you're buying two 8 ohm speakers, your wiring options using both wired together to a single input jack are:

* parallel = 4 ohms
* series = 16 ohms

If you [i]really[/i] need a 4ohm / 8 ohm option, you'd could go with switchable option of one one speaker out of circuit (8 ohms) and both speakers in circuit (4 ohms). OTOH, if your amp has two speaker outputs and supports 4/8 ohms, you could always wire the speakers in 'stereo' - ie two jack sockets on the cab. All sounds a bit fiddly to me, but hey, let's push the envelope.

[escholl]

[quote name='JackLondon' post='885386' date='Jul 4 2010, 12:17 PM']2. I would like to put the cab on wheels so my question is : Does it matter if the main orientation of the speakers is horizontal or vertical ? I would ideally like to have it vertical, it just looks cool that way.[/quote]

The horizontal dispersion will theoretically be more even with the drivers arranged vertically (which is good). So if you like the way it looks too, then I'd say go for it vertical.

[RichardH]

[quote name='skankdelvar' post='885997' date='Jul 5 2010, 02:46 AM']If you [i]really[/i] need a 4ohm / 8 ohm option, you'd could go with switchable option of one one speaker out of circuit (8 ohms) and both speakers in circuit (4 ohms). OTOH, if your amp has two speaker outputs and supports 4/8 ohms, you could always wire the speakers in 'stereo' - ie two jack sockets on the cab. All sounds a bit fiddly to me, but hey, let's push the envelope. [/quote]


Whacky alternative wiring - I put three switched jacks on the back of my 2x12, and wired them so if you use the centre jack is runs both drivers in parallel for 4 ohms, and each of the other two sockets just connect to a single driver, so it can be sued by two people if needed.

[stevie]

[quote name='JackLondon' post='885559' date='Jul 4 2010, 04:58 PM']Anyone know where I can get these in UK > [url="http://www.reliablehardware.com/mediumrecessedtiltcasterhousingblack.aspx"]http://www.reliablehardware.com/mediumrece...usingblack.aspx[/url][/quote]

That looks like an Adam Hall wheel.

The mesh looks like some kind of fencing product but I've no idea where you can get it from. EBS use some neat fencing wire for their grilles that looks even nicer.

[stevie]

[quote name='Dubs' post='885550' date='Jul 4 2010, 04:31 PM'] bargain! How can the speakers cost more than the complete cab?![/quote]

Buying power plus selling directly to the public. It's an unbeatable deal as long as the logo is removable.