Speaker Cabinet plans

george wrote:

> There is a LOT more to making speaker enclosures than simply
> woodworking...you need to design them for the specific driver(s) that you
> intend to use...dimensions and rigidity are critical issues. If you wish to
> pursue AND do a good job and don't have an electrical engineering degree,
> you'll need some design software. Check out www.partsexpress.com for
> advice, parts, and software + there is some free software online for simple
> designs.

When it comes to guitar cabs, it don't take a rocket scientist.

The history of guitar cabs is to just slap them together without regard
to speaker parameters. There are a couple of general rules when it
comes to sealed cabs, like 4x12. The smaller the interior volume, the
greater the loss of lower octaves, and the more of a low mids peak.
Larger volume gets you more bottom end and smoother response (less lower
mids peak).

There are more complicated cabs. My favorite is the OLD Hiwatt 4x12
with the rear slot. I also have a front loaded Hiwatt with four round
"ports" that are just cut outs in the baffle. Then there's the Mesa
Thiele and the Genz Benz and others. I converted an empty Marshall
JCM800 2x12 combo cab into a tuned cab using a computer program
(Blaubox, freeware). It was NOT tuned the same was as you would a
subwoofer, but tuned to compensate for the tight volume when I made the
combo a SEALED cab. It uses British (not Chinese) Celestion Vintage
30's, and sounds great.

So, you can go low tech, or high tech, depending on tastes and needs.
Tuning is really only necessary for PA, Bass and Keyboard. There is no
need to tune the bottom end of a guitar cab. Neither Leo or Jim ever
did. They just picked a convenient size, cost efficient materials, and
built them.


>
> "Chris Berry" <[email protected]> wrote in message
> news:[email protected]...
>
>>"Ted" <[email protected]> wrote in message
>>news:[email protected]...
>>
>>>You have some good points.
>>>Woodworking is one of my hobbies. They are for a friend who wants cabs
>>>for
>>>playing guitar on stage (bars, etc).
>>>
>>>I need to learn about baffling, etc. Would the speakers be wired in
>>>series
>>>or parallel?
>>
>>I typically use 15mm ply for baffles and 12mm for the rear.
>>Wiring depends on the driver impedance and the desired cab impedance...
>>cb
>>
>>
>
>
>

You have some good points.
Woodworking is one of my hobbies. They are for a friend who wants cabs for
playing guitar on stage (bars, etc).

I need to learn about baffling, etc. Would the speakers be wired in series
or parallel?

I like the ides of the truck bed liner for a tough finish.
"Chris Berry" <[email protected]> wrote in message
news:[email protected]...
> That's a very vague question. 2x12", 4x12" for bass? guitar? what's the
> objective? Weight? portability? roadworthiness? Constrained by driver
> choice? Looking for a classic? Looking to improve a classic?
>
> Assuming it's for guitar, the lightest 2x12" you could build is probably
in
> the 16kg range. That's going for some fancy construction for panel damping
> and bracing. It's my favorite as you can always make another cab at some
> point and it tends to be cheaper as well.
>
> 4x12"s out of 3/4" marine ply will cost you a LOT and weigh even more -
> expect 45kg or even more if you go for Celestion Blues!
>
> Want more bass? How about a tuned enclosure to make the bass louder? Why
not
> try both and make a removable baffle? Why not make 2x1x12"? is it for
> modelling amps? In which case go for a PA type design and even use tweets!
>
> With regard to covering, do yourself a favour and get a shop to spray on
> some epoxy-based truck bedliner. The stuff is only about 100x tougher than
> tolex and much less labour intensive. I apply the stuff on my cabs myself
> with a roller and it's pretty easy to work with so long as you do it
> outdoors - and remember that anything it touches usually needs to be
ditched
> afterwards (GET THE LATEX GLOVES OUT).
>
> What kind of joinery are you capable of? tools? corner clamps make things
a
> LOT easier - box joints are pretty tricky rabet isn't bad at all if you
have
> the precision tools but a standard reinforced but joint (no joke) is the
> simplest and executed well is good enough.
>
> Just remember, draw up as many plans as you can, leave tollerances, use
> flush trims as no board is ever flat or square and when you're ready to
go,
> you'll probably want to dith the plans and do your own thing - at least
> you'll have thought out some of the problems ;)
>
> e.g. you can't have a front lip (strip of wood along the front to make the
> wood look thicker) and internal reinforcement without having the baffle
> permanently attached - or sitting level with the front of the cab (bad
> idea). Either the front or back must be removable both can be. Remember
that
> grill cloth, spray-on epoxy, carpet and tolex all have thicknesses ;-)
>
>
> cb
>
>
> --
> =================================
> Some people have something to say... others have to say something!
>
>
>
>

That's a very vague question. 2x12", 4x12" for bass? guitar? what's the
objective? Weight? portability? roadworthiness? Constrained by driver
choice? Looking for a classic? Looking to improve a classic?

Assuming it's for guitar, the lightest 2x12" you could build is probably in
the 16kg range. That's going for some fancy construction for panel damping
and bracing. It's my favorite as you can always make another cab at some
point and it tends to be cheaper as well.

4x12"s out of 3/4" marine ply will cost you a LOT and weigh even more -
expect 45kg or even more if you go for Celestion Blues!

Want more bass? How about a tuned enclosure to make the bass louder? Why not
try both and make a removable baffle? Why not make 2x1x12"? is it for
modelling amps? In which case go for a PA type design and even use tweets!

With regard to covering, do yourself a favour and get a shop to spray on
some epoxy-based truck bedliner. The stuff is only about 100x tougher than
tolex and much less labour intensive. I apply the stuff on my cabs myself
with a roller and it's pretty easy to work with so long as you do it
outdoors - and remember that anything it touches usually needs to be ditched
afterwards (GET THE LATEX GLOVES OUT).

What kind of joinery are you capable of? tools? corner clamps make things a
LOT easier - box joints are pretty tricky rabet isn't bad at all if you have
the precision tools but a standard reinforced but joint (no joke) is the
simplest and executed well is good enough.

Just remember, draw up as many plans as you can, leave tollerances, use
flush trims as no board is ever flat or square and when you're ready to go,
you'll probably want to dith the plans and do your own thing - at least
you'll have thought out some of the problems ;)

e.g. you can't have a front lip (strip of wood along the front to make the
wood look thicker) and internal reinforcement without having the baffle
permanently attached - or sitting level with the front of the cab (bad
idea). Either the front or back must be removable both can be. Remember that
grill cloth, spray-on epoxy, carpet and tolex all have thicknesses ;-)


cb


--
=================================
Some people have something to say... others have to say something!

"Ted" <[email protected]> wrote in message
news:[email protected]...
> You have some good points.
> Woodworking is one of my hobbies. They are for a friend who wants cabs for
> playing guitar on stage (bars, etc).
>
> I need to learn about baffling, etc. Would the speakers be wired in series
> or parallel?

I typically use 15mm ply for baffles and 12mm for the rear.
Wiring depends on the driver impedance and the desired cab impedance...
cb

"george" <[email protected]> wrote in message
news:[email protected]...
> There is a LOT more to making speaker enclosures than simply
> woodworking...you need to design them for the specific driver(s) that you
> intend to use...dimensions and rigidity are critical issues. If you wish
to
> pursue AND do a good job and don't have an electrical engineering degree,
> you'll need some design software. Check out www.partsexpress.com for
> advice, parts, and software + there is some free software online for
simple
> designs.

And pretty much none of it actually applies to making guitar cabs... (this
is a guitar group)...
Thiele-small parameters are good up to a point... they'll let you guestimate
how the enclosure will affect the sound, the port resonance, air speed in
the port but NOT if it will sound good or not. That's simply not possible
with the tools available. Don't forget also that speaker manufacturers have
considerable variance in their parameters and parameters change over time.
For your typical guitar enclosure, the dimensions are determined by the
physical application. Simply put, It's got to be big enough to put that head
on it, under that combo or below the rack box you're using. Then the volume
should be about right - just remember that the 4x12" was originally an 8x12"
that was sawn in half whose dimensions were big enough to place the head on
top of...
Honestly, for guitar you really don't need to fuss much about the
parameters. an enclosure with a big enough internal volume (1-2cuFt/12"
speaker is about right). Some people prefer baffles and cabs to be made out
of pine (early Fender - as that was cheaper than ply)- others (Marshall)
tended to go for big marine ply but not any more - check the weight
differences of the 4x12" cabs and compare with the reissues. It's always
easier to copy an existing design though.
I've heard great sounding cabs made out of chip board, ply, pine, MDF,
Ply/bitumen mat sandwich, seen internal carpeting work well, glass wool on
the inside (I HATE that stuff), foam, excessive bracing, minimal bracing,
extreme roadworthiness - pretty much anything you can think of. At the end
of the day, I've highlighted *MY* major considerations when building a cab.
Remember: Weight, size, drivers, cosmetics.
Sound can always be fixed with internal damping and bracing but it's good to
have a rough idea of what you'll be needing.
I've just finished a lightweight 2x12" that's slightly deeper than usual -
33cm deep. It fits a Marshall head on top of it at about 50cm off the deck
or a rack case at stack height when it's on it's end. At 18kg it's
ultra-light weighing about the same as a Marshall 1x12", sounds good and is
louder than a 4x12".
Construction is 9mm ply for the casing with a 12mm front and back. Low
density fibreboard is glued on to the panels on the inside with acoustic
foam stuck on to that. (I always make sure that full contact is made with
the adhesive. There are next to no internal resonances as a result (relying
on calculation for resonance separation isn't reliable)
cb

You might also want to post this question in another group, alt.guitar.bass.
There are some very active speaker builders who frequent the group.

"Ted" <[email protected]> wrote in message
news:[email protected]...
> Does anyone know where I can get free plans for building cabinets? 2x12,
> 4x10.
>
> Thanks
>
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There is a LOT more to making speaker enclosures than simply
woodworking...you need to design them for the specific driver(s) that you
intend to use...dimensions and rigidity are critical issues. If you wish to
pursue AND do a good job and don't have an electrical engineering degree,
you'll need some design software. Check out www.partsexpress.com for
advice, parts, and software + there is some free software online for simple
designs.

"Chris Berry" <[email protected]> wrote in message
news:[email protected]...
>
> "Ted" <[email protected]> wrote in message
> news:[email protected]...
>> You have some good points.
>> Woodworking is one of my hobbies. They are for a friend who wants cabs
>> for
>> playing guitar on stage (bars, etc).
>>
>> I need to learn about baffling, etc. Would the speakers be wired in
>> series
>> or parallel?
>
> I typically use 15mm ply for baffles and 12mm for the rear.
> Wiring depends on the driver impedance and the desired cab impedance...
> cb
>
>

That would entirely depend on the impedance the amp was intended to drive,
the impedance of the speakers and how many of them there were.

"Ted" <[email protected]> wrote in message
news:[email protected]...
>
> Would the speakers be wired in series
> or parallel?
>
> I