Thread: how to build a quad box or a twin box?

Quad boxes are one of the main reasons I dumped all my electric s**t and went acoustic. Got sick of lumping quad boxes and heads around....before I got my license I even walked a 50 kg amp head 2km home from school one day.

Can I borrow those books Soundman? I'm eventually looking at building a 1 X 12 speaker box to go with my SWR 2 X 10's and I do a lot of slapping and popping too!

There's a guy that posts a lot on talkbass.com that designs speaker boxes professionally. He's got his own website where you can buy plans to build them yourself. His boxes though are somewhat not the normal stuff you see out there but apparently the designs are all amazing. He even has a support forum for builders of his stuff.

http://www.billfitzmaurice.com/

Toddles,

If you're working to a budget and/or are fixed on a twin 12" design then this probably won't be for you but it may be food for thought.

One of, if not the nicest/best sounding quads I've ever encountered was made by Mesa Boogie. It was probably about 2" smaller in width and height than a standard Marshall "1960" slant quad and it was very soldily built (thick sides, etc). It was a half closed, half open back design......top speakers were open, the lower pair sealed BUT the cruncher was the speakers, they were Boogie's (maybe made by Eminence in the US) and rated at 150 watts each.......Yep, the box had a rating of 600 watts. The friend that owns it uses his Boogie Mk IV combo to power it and we have used it with a Marshall head and also a Laney VC-100 combo (as a head). Regardless of what power, it always sounds superb.

Boogie later dropped the speaker rating to 300 watt and they alledgedly lost the sound. If I ever find a 600 watter s/hand while I'm holding some cash I won't hesitate to grab it.

The watt's on a speaker dont realy mean much, just means how much thermal abuse they will take.(more watts more heat)
Its like comparing 2 cars, 1 has 100kw and weighs 1000kg and the other is 150kw/2000kg... which is faster? There's to many variable's to compare in speakers to judge them by just watts... hence the MBoogies 150watters had a better sound than the 75watters... its nothing to do with watts, its more like a differing in design's/materials and TS specs.

As far as any branded quad.... sorry never very impressed.. almost without exception they are chipboard or mdf.... a quad is one of the most undesigned speakers there is.... apart from a few exceptions they are a square box as small as possible to fit 4 speakers in.
Any imported guitar cabinet will invariably be overpriced because of the cost of shipping all that air arround and the simple fact that here in AUS timber sheet goods are as well priced as you will get just about anywere in the first world.

I'm afraid I'm not the man to give an opinion about the relative merits of one brand of guitar anything over another because I am not a player.
With gituars and anything associated with them beauty is in the ear of the beholder.... styles, preferences and opinions vary so much....... its like getting into a discussion about sharpening.

One thing I do know is that Boogie are clever blokes (as far as guitar dudes go) the difference has always been that boogie actualy spend time doing SOME design and thinking about things other than how quickly and cheaply they can bang out a product.
That boogie quad is in fact not a quad at all it is two twin boxes bolted together getting the best of open back and closed back sound.

Almost without exception quads are closed back.

On the subject of eminence.... most of the american manufactured amps of the tradional period would have had eminence manufactured speakers in them. It was only in relativly recent times that eminence actualy sold speakers under their own brand.
They always were and still remain an OEM manufacturer ther is hardly a sound reinforcement or musical instrument brand world wide that hasn't at one time or another used eminence speakers or had their speakers built in the eminence factory including the major speaker brand names.

eminence still has all the jigs and dies used for its early designs and started re issuing some of the old designs exactly as originaly built for the retro guitar market.
I know celestion is also reissuing vintage series too.

If you want an absolute balltearer of a bass quad box look at the eminence 200 watt 10" ( cant remember the numbers). That is an absolute pearler of a speaker the magnet isn't much smaller than the hole it bolts into.
The driver is smooth sweet and clean ( to a point ) and has good efficiency.
It runs out ot top end ( cone mass and voice coil inductance ) or at least gets a bit ragged arround 2Khz or so. but for bass thas OK.
That 200 watt power rating..... yep its for real.

That give you a an 800 Watt quad box:eek: ..... you will probaly need a 1600 Watt amp to cause it stress now thats balls the size of socker balls.
Now a box like that is completely useless except for impressing school boys or for getting flem of your chest... then perhaps you want to jam with a guy in the next state.
I have a horn loaded mid high pack with two of those drivers in it & its sweet as a nut and trucks like a kenny.

As for loaning my speaker books......mmmmmm.... no.
But I could coppy a couple of pages...

As for slaped bass that single 15 and two 10's in two seperate boxes isn't a bad plan either, very flexible and easied to lug.

In truth high power drivers arent what is needed for instrument applications.
High power means a different then now than it did in the past.
600 and 1000 watt real watts drivers are available....Don't get me started on that one.
Highere power means higher cone mass and higher voice coil inductance which both reduce high frequency production and efficiency and transient response also suffers.

With bass you are looking for two things moderately low frequency response (not all that low 80-120Hz or so) and for slaped bass transient response.
mid frequency response...... yeah suppose. Top end..... Gituars do not produce top end. 6.5Khz is not top end and thats where most guitars top out. So when a gituarist says top end he probaly means High Mid.
(Particularly if he's been playing heavy rock & roll for 10 years or more because his hearing stops about there .)

This post is getting way too long & I'm staryingvto ramble so I'll stop here

cheers

Heres another set of plans
This is for a 4x12 Cab Box
dayvo

4 x 12" now there's a back breaker

With some of the newer better 8" drivers out there a 4 x 8" is a viable option.

A quad box isn't at all complicated and there "is no design work" involved.
They are just a box barely big enough to hold the drivers.
Mostly there is no damping (that's unnecessary cost), but some damping will smooth the response a bit but dont go overbaord, it'll make the box sound bland. All of two adjacent sides and half or all of the back would be about right.

The timber always looks thick from the front because the front edge is double (or more) thickness and the baffle is traditionaly fitted from behind and fixed to the back of this double thickness.

15mm CD ply is a good and reasoable choice for a quad.

just remember to leave at least 10mm (and not much more) clearance all round and between the outside dimensions of the speaker frames.
It is necessary to brace both the baffle (there aint much wood left) and the back as they are big square floppy bits of wood and there is considerable air preasure inside one of these.
Many of the cheaper designs just stick a lump of pine front to back right in the centre, this is a bare minimum.
A 50 to 75mm strip of ply on edge top to bottom or side to side both front & back then tied together with a strip about 100mm wide in the middle is strong & effective without getting in the way.
Make sure your joints are good, strong and air tight.

most of the early guitar cabs and many of the modern ones are built with a front baffle that just screws in from behind and a back that just screws on.
The speakers load from the rear with grill cloth wraped arround the baffle

For a high power quad this is just not adequate.

I recommend full glued and screwed construction with the speakers loading from the front.
For mounting the speakers, chipboard screws hold adequately in 15mm plywood but my preference is 3/16" T nuts and allen key bolts.

making a slope front only makes the whole deal a little harder.

cheers

Harry,

Sorry if it seemed I was attributing the alledged sound difference between the two Boogie quads to the wattage......I wasn't but unfortunately, to my knowledge, identifying the wattage is the only way to quickly differentiate between the early and the later models.