# The ideal speaker cab...what is needed?



## greco (Jul 15, 2007)

There has been a lot of discussion in the past about speaker cab construction...with MANY opinions.

Just to keep this simple, what would be some of the essential factors contributing to the tone produced by a cab for guitar (not bass)? 

Please don't say "the speaker"...that is a given !

Let's stay with a 1 x 12" OPEN BACK and discuss such things as:

1) overall dimensions...this is the aspect that interests me most

2) materials used to make the cab (i.e., MDF vs pine vs Baltic birch plywood etc, the thickness of material, etc

3 Baffle...material, thickness, floating or not, etc 

4) any other factors (Hamstrung is bound to mention the colour of the tolex...LOL...it is an old joke between us)

Thanks

Cheers

Dave


----------



## screamingdaisy (Oct 14, 2008)

I'd say, copy whatever Mesa's doing with their current 1x12 cabs. I've heard/owned some of their earlier 1x12 combos and they tended on the side of boxy at times, but their newer stuff is a little wider... and they sound outstanding.

I don't like saying things like "sounds as big as a 4x12", 'cause they don't. I will say that I don't feel like the cab is hampering the performance of the speaker or the sound of the amplifier.


----------



## tbellisario (Apr 14, 2010)

What Mesa is doing is using the same Theil parameters as published by Altec Lansing several decades ago. I build cabinets and have used many materials, MDF, Birch Ply, Solid pine with finger joints. If the box is built large enough and stiff enough it will sound good.
I started out to be a cork sniffer when it came to cabinet material and construction until I started building and comparing my own. I have some I prefer sure. Largest factor is open vs. closed back, floating vs. fixed baffle board that make the largest contribution design wise as far as the basics go. Cabinet material is way down on the list of contributing factors and contrary to what many would like to have us believe. Covering and glue do not make a diff. 
The unfinished MDF with the JBL in the pic. is the design MESA uses but with a full grill. Outstanding balance and tone.
I have also recovered every manufacturers cabinets possible. MESA uses 3/4" glued MDF, Marshall uses the cheapest particle board you can find.
E-Mail me for pics I cannot see how to attach pics to established threads.
[email protected]


----------



## greco (Jul 15, 2007)

*tbellisario .......... Welcome to the forum. * ENJOY and post often.

Thanks for the responses.

I 'd be very interested in more dicussion around *floating vs. fixed *baffle (this really baffles me....GROAN) 


*AND* what you would consider *the ideal outisde dimensions for a 1 X 12" cab.* I'd like to compare this to existing 1 x 12" cabs.

Cheers

Dave


----------



## torndownunit (May 14, 2006)

I use one of the Avatar 1x12 cabs which is a really deep cabinet (and closed back). It sounds incredible. I actually wasn't specifically looking at that model, I just put up an ad awhile back looking for any 1x12 as I had a few gigs coming up and needed something. I can not believe how huge and bassy is sounds for a 1x12 cab. For my tastes, the best I have heard.


----------



## greco (Jul 15, 2007)

Thanks TDU. How deep is your cab?

I'm hoping the owner of Saxon Cabs. sees this thread and comments.

Cheers

Dave


----------



## tbellisario (Apr 14, 2010)

The floating baffle concept is basically using the baffle as a resonator. If constructed properly the baffle will vibrate with the speaker giveing more surface area to resonate. Think resonator acoustic guitars. Most people can hear the difference between a floating and non floating baffle board.
There are two key elements to correct construction.
1- The baffle board cannot be too thick, best kept less than 1/2" in thickness. Fender used 5/16" pine.
2- Must be attached in 4 corners only, and not screwed into a surounding frame rail on all 4 edges like a Marshall cabinet for example. If too firmly attached to the cabinet you loose the effect. The best examples are Fender Tweed designs. With the grill cloth being somewhat spongy in compression the baffle board is screwed into the top and bottom lip of the cabinet from the inside. Or sometime you see a screw from the outside but backed up with a "T" nut in the 4 corners.
This spongy grill cloth sandwich keeps the baffle from being too firmly attached to the surrounding cabinet. Hence the term "floating"


----------



## Wild Bill (May 3, 2006)

greco said:


> *tbellisario .......... Welcome to the forum. * ENJOY and post often.
> 
> *AND* what you would consider *the ideal outisde dimensions for a 1 X 12" cab.* I'd like to compare this to existing 1 x 12" cabs.
> 
> ...


Dave, it doesn't matter! At least, not with a regular guitar cab. A regular guitar doesn't go down far enough into the lower bass frequencies for the cabinet dimensions to become a factor. Basically, it's just a box to hold the speakers up!

All the other info in the thread about high density wood and stuff does matter. The operative factor is that the wood should not have any voids in it, like cheap plywood with holes in some of the lamination layers. These cause bass energy "suckouts". MDF is the best because it is made of sawdust and glue paste. Voids would be impossible. It IS damn heavy and hellish hard on router bits, though. Old-fashioned solid pine is a good choice except the modern stuff tends to have a high moisture content. If you can dry it out for a couple of years without any warping that would be best.

Bass guitar or PA /hifi speakers are a different story. They are asked to reproduce much lower bass frequencies, where the wavelengths are long enough that the cabinet dimensions DO matter! The cabinet still works but you need specific wavelengths that acoustically reinforce those lower frequencies, bringing up their amplitude so that you get a more even bass response in the lower end.

Cabinets can be built out of other materials than wood! During the Golden Years magazines featured articles on building cabs out of clay sewer pipe, concrete, "sandwiches" of plywood with 1/2" layers of dry construction sand, glass and many others. The only caution was that "shiny" surfaces could reflect the treble waves in some dimensions that would cause the cab to sound TOO bright! This applies to wood as well. It's an easy problem to cure. You just staple some batt insulation on any 3 internal sides of the cabinet to kill the reflections.

WB


----------



## greco (Jul 15, 2007)

Thanks for the responses...the baffle information was interesting and informative.

Wild Bill...I know we have talked about this before, I just wanted to see what kind of discussion would arise from this thread.

I have a very small 1 x 12" cab and it never seems to sound as good as my larger 1 x 12" cab. Who knows, could be "all in my ears/head"...LOL

Cheers

Dave


----------



## JSX/6505 (Nov 18, 2007)

Cabinet dimensions most certainly make a difference in the tone a cab reproduces. Two inches might as well be two feet. Maybe not if you are playing low volume country, blues or chicken pickin', but for modern rock and high gain metal cab dimensions play a big role.
I also wouldn't recommend using MDF for a cab constuction. Sure it's pressboard, and very dense, but it is also universally known as having terrible resonant qualities and is susceptible to humidity and other forms of moisture.

For smaller cabs, like 1x12's, a ported design is optimum. 
This helps the cabs sound less boxy and directional. The bass is also bigger and clearer sounding.


----------



## bobb (Jan 4, 2007)

greco said:


> 4) any other factors (Hamstrung is bound to mention the colour of the tolex...LOL...it is an old joke between us)


Black sounds better than any other color...nuff said. 9kkhhd


----------



## greco (Jul 15, 2007)

JSX/6505 said:


> Cabinet dimensions most certainly make a difference in the tone a cab reproduces. Two inches might as well be two feet.


Do you believe that this is true for open back cabs, specifically?

Cheers

Dave


----------



## greco (Jul 15, 2007)

bobb said:


> Black sounds better than any other color...nuff said. 9kkhhd


You just had to 9kkhhd ...didn't you....LOL

Dave


----------



## tbellisario (Apr 14, 2010)

The Theil parameters used by Electrovoice and Altec Lansing show a box 23 3/4" high x 19" deep x 17" wide. This gives an internal volume of 3.2 cubic feet. Also a port on the end 2"x 16" As I mentioned in my previous post I built one of these and front loaded a !2" JBL that give great sound for a "smallish" box with good bass response. Internal volume is very important. Numero Uno. This is the major reason small amps sound small. The first comment that someone has when they plug their little Blues Junior into a 4 x12 is Holy Crap! I didnt think my amp could sound so good or BIG! It is not always the speaker size or manufacturer but the size and design of the box. You asked what MESA was doing for their 1x12, this is it if you are after that sound. They also primarilly load with Celestion Vintage 30's which give good range. Go on their web site and see for youself.


----------



## GTmaker (Apr 24, 2006)

Are there detailed speaker cabinet dimention specs available on the WEB ?
Ported designs are profered but all designs welcomed.
thanks in advance


----------



## Wild Bill (May 3, 2006)

greco said:


> Thanks for the responses...the baffle information was interesting and informative.
> 
> Wild Bill...I know we have talked about this before, I just wanted to see what kind of discussion would arise from this thread.
> 
> ...


No, it's not necessarily just in your head, Dave! The volume of the cab will have some effect, even for regular guitar speakers. The rigidity of the box is VERY important! Any "wiggle" will suck sound energy.

Closed or open back will also make a HUGE difference!

When you build a 4-12" you already are forced to a certain minimum box dimension. Making it bigger will make it more efficient (louder) but being practical forces you not to go much larger.

Some guys will talk about Thiele parameters and the like but it's hard to explain why you would use formulae, ports and stuff where you plug in frequencies below what a regular guiltar can play! Your bottom E string is just below the 100hz mark. Critical dimensions and ports are what get a cabinet down to 20 Hz or so! The only thing coming out of a regular guitar in that range is 60hz hum!

So as a general rule, don't worry about tone. The dimensions aren't critical for any of the frequencies that your guitar can generate. Bigger will boost efficiency, which means overall volume. Typically, with a 4-12" you're running enough power into it that extra efficiency won't really matter much. Single 12" designs can benefit from increased cabinet volume. That's why the typical Traynor YGM-3 Guitar Mate of the closed back design sounds louder for a 20 watt amp! Even with the original lameass Marsland speaker it will outperform other amps in its power class.

Open back will "sound" louder, since it washes out in a cardoid "figure 8 pattern". Closing the back makes the cab more directional and also "tighter", since the cone moves against more back pressure.

That's my story and I'm sticking to it!

WB


----------



## tbellisario (Apr 14, 2010)

I just wanted to clarify my earlier post on cabinet size.
Ther are some variables in design that cancel out other good attributes. 
For instance if I build a cabinet and expect the sound characteristics of a floating baffle and the size is too small, the baffle will not resonate and I loose the desired effect of the floating baffle. It is a system of details that work togther.
Look at some of the examples from the past like Fender Bandmasters and Showmans, Acoustic, Sunn, Altec A7's what you got was good sound at the cost of large cabinets. Some have bass reflex designs, others just ported but mostly large volumes of air behind the speakers.
In an effort to make combo amps portable and affordable manufacturers have resorted to lots of EQ and modeling and get away sometimes with smallish cabinets.


----------



## screamingdaisy (Oct 14, 2008)

tbellisario said:


> They also primarilly load with Celestion Vintage 30's which give good range. Go on their web site and see for youself.


Most of Mesa's 1x12s are loaded with an MC-90. It's a deeper, fuller range speaker with more low mids, a smoother upper midrange and dark-ish top end. It works well in both open back and ported designs.

The V30s are really only used in cabs that were originally labelled as Rectifier cabs, all of which are closed back except for the RoadKing versions... which have sealed V30 on one side side and a rear ported MC-90 on the other.


----------



## mrmatt1972 (Apr 3, 2008)

I've read 2 books about speaker cab design. One was an old one by Bell Labs (borrowed so I don't have it any more) and the other is London Power's speaker cab book. The books both take very different approaches, but the London Power one is more aligned for GUITAR than the Bell one, which was more hi fi. What I learned from Bell was that an ideal enclosure is rigid, especially the baffle, and contains enough air (or air + acoustic insulation) to form an "infinite baffle." An infinite baffle would completely isolate the forward cone excursions from the rearward ones. The air in a closed cab also provides a mechanical spring effect making the speaker more efficient and less prone to overheating. A twelve inch speaker requires something like 3600 cu inches of air (note that means INSIDE dimensions - I can't find the actual figure, but that's close, and too much volume is better than not enough). One caveat is to NEVER make a cube shaped closed cab. All that is out the window though when we talk about open back guitar cabs.

Usually, a 1x12 cab is much smaller than the 3600 cu inch ideal, so open back becomes a good idea. 1. it allows the speaker to move freely, where a too small closed cab damps the speaker movement. 2. It's cheaper to build due to less material. 3. It gives a more room filling sound due to the rearward excursions being send out the back.

It's not quite a "speaker holder upper" like Wild Bill said, but it is close. In my experience, I've tried to make open back cabs as close to the 3600 cu in ideal as aesthetics will allow, and then make it only "semi" open backed. i.e., 1/2 or less of the back is open. 

London Power would advocate making a slightly oversized closed back 2x12 cab and only installing one speaker in it while leaving the other speaker hole open. This gives you a "detuned" cab - they sound great.

YMMV

Matt


----------



## washburned (Oct 13, 2006)

the best theoretical sound from a speaker would be an "infinite baffle", where all sound would only come from the front of the cone: an enclosure is a compromise as the sound from the back of the speaker bounces off the inside of the enclosure and either dampens or reinforces certain frequencies, which are dependant on the cabinet dimension. A port is a way of letting this sound out, but then the question of phase begins to enter: frequencies that come out of the port too late tend to cancel frequencies from the front of the speaker, so the port must be "tuned": a benefit is that the port can be tuned to reinforce, amplify, certain frequencies, especially low ones. Larger is better as it more approximates the infinite baffle; in fact enclosures large enough that most resonant frequencies are negligible are often referred to as infinite baffle enclosures. For electric guitar amplification, ports are unneccessary in a sealed cabinet of sufficient volume; the difference in sound between a sealed enclosure and open back is in the cancelling/reinforcing effect of the sound coming the long way round from the back interacting with the sound from the front.front

obviously I type too slow.


----------



## greco (Jul 15, 2007)

mrmatt1972 said:


> London Power would advocate making a slightly oversized closed back 2x12 cab and only installing one speaker in it while leaving the other speaker hole open. This gives you a "detuned" cab - they sound great.
> 
> YMMV
> 
> Matt


I had an old 2 x 12" closed back cab that I bought for very little. It was huge and well built and I tried the *detuned* concept...it was certainly a BIG sound !!

Cheers

Dave


----------



## Sneaky (Feb 14, 2006)

I've been very impressed with a custom EV/Theile spec hardwood cab with an EVM12L. Best 1x12 I've ever heard.

I used to have a couple Bogner 1x12 ported cubes that were pretty good too, but the Theile design with the rectangular port sounds way bigger.


----------



## Wild Bill (May 3, 2006)

It might help some folks if we describe an "infinite baffle".

At its simplest, picture a BIG wide and tall featureless wall! Now put a hole in it and mount a speaker in the holel

All the acoustic energy will come forth from the hole. None of the air from the moving cone can get behind the wall, to mix with any air moved at the rear of the cone.

This is the perfect, laboratory speaker situation. An infinite baffle! The baffle is of course, the entire wall!

When we make a cab we are cutting into that infinite baffle of a wall, bending back sections of it and forming an enclosure. Any shape that enclosure takes is going to be a compromise compared to the original infinite baffle. That's why dimensions and such become important to the lowest efficiently reproduced frequency and the volume to the overall "loudness".

The rage today is for smaller and smaller cabs. They tend to use ports, ducted ports, waveguides, "space age" cones and magnets and such in efforts to extend the frequency range in order to have good tone. They can do moderately well but the small volumes mean VERY low efficiencies, no matter what, period and end of story. That's why modern small apartment hifi cabinets need hundreds of watts to drive them! They have ridiculously low efficiency ratings. Tube hifi equipment running maybe 10 watts can take that Pat Travers vinyl LP, feed it into those bigass 1970's hifi speaker cabs and blow the walls out!

The same is true for guitar amp cabs, especially bass cabinets. I vividly recall being at a practice in a basement, sitting beside a modern Ampeg 4-10 bass cab driven by a 300 watt solid state SVT. The amp was dimed yet I wasn't deaf! I asked the player if that was normal and he said, "Yep! That's as loud as she gets!". Immediately I knew it was the lameass modern cabinet. Easier to carry, perhaps. Still, it needed those 300 watts just to be loud enough for small clubs. Back in the early 70's bass players would run a 50 or a 100 watt head into a 2-15" or even 2-18" cab as big as a small refrigerator! Traynor used to put wheels along a bottom edge and handles at the top so you could "dolly" it onto the stage. We used to fill high school gymnasiums full of young dancers from front to back with LOUD music, with the bass amp on 3!

I've have many books on speakers and cabs but the one I treasure most is a classic from 1949 called "Sound Reproduction" by G.A Briggs. He worked for the Wharfedale Wireless Works in England. The company is still known for high end speakers today. For both theory and practical knowledge that man knew more about how things work than anybody I've read today and he knew it 70 years ago!

WB


----------



## tbellisario (Apr 14, 2010)

greco,
You started this thread with the question of cabinet size for a 1x12 and what MESA had to offer. 
I have built the Theile cabinet as Sneaky has shown in his photobucket pic. the one with the wicker grill covering. Build plans are available on the internet.
I would be willing to let you borrow my unloaded cabinet for a few weeks. Whatever 12" driver you have will front load into this cabinet and you can test drive it to help you decide.
I see you live in Kitchener, I work in Mississauga. E-Mail me if you are interested. [email protected]


----------



## Wild Bill (May 3, 2006)

greco said:


> I had an old 2 x 12" closed back cab that I bought for very little. It was huge and well built and I tried the *detuned* concept...it was certainly a BIG sound !!
> 
> Cheers
> 
> Dave


Tbelisario has made you a generous offer, Dave! If you decide that is the style for you, you should also include the wicker grille in your design. Grille cloth is essentially transparent at mid and low frequencies but some materials do block a bit of the highs. Depending on how bright the speaker or the amp is anyway this can mean the grille cloth moves the response into an area you may not like or you may absolutely LOVE!

I mean, people pay money for "beam blockers" and stuff to change the highs coming out of a cabinet!

Just another factor to consider. Besides, some of us think the wicker looks kinda retro and cool!

WB


----------



## greco (Jul 15, 2007)

tbellisario said:


> greco,
> You started this thread with the question of cabinet size for a 1x12 and what MESA had to offer.
> I have built the Theile cabinet as Sneaky has shown in his photobucket pic. the one with the wicker grill covering. Build plans are available on the internet.
> I would be willing to let you borrow my unloaded cabinet for a few weeks. Whatever 12" driver you have will front load into this cabinet and you can test drive it to help you decide.
> I see you live in Kitchener, I work in Mississauga. E-Mail me if you are interested. [email protected]


Your offer is greatly appreciated. 

I actually started this thread more for discussion and educational purposes. I am tempted to take you up on your offer to try your cab (as I enjoy gear) but I am presently trying to reduce the amount of gear that I have accumulated.

Again, thanks for the generous offer.

Cheers

Dave


----------



## mrmatt1972 (Apr 3, 2008)

greco said:


> but I am presently trying to reduce the amount of gear that I have accumulated.


sigiifa

I didn't think that was possible.


----------



## megadan (Feb 5, 2006)

If you really want to learn a lot about the science of cabinets, I'd suggest posting on a bass or PA forum. (guitarists talking about cabs sort of makes me giggle).

Here are some starts:
http://www.talkbass.com/forum/archive/index.php/t-66416.html
http://www.talkbass.com/forum/archive/index.php/t-272412.html
http://www.talkbass.com/forum/archive/index.php/t-177006.html
http://www.talkbass.com/forum/archive/index.php/t-443538.html
http://www.talkbass.com/forum/archive/index.php/t-23536.html
http://www.talkbass.com/forum/archive/index.php/t-81554.html
XF Guitar Cabs


----------



## greco (Jul 15, 2007)

megadan said:


> 'd suggest posting on a bass or PA forum...... *(guitarists talking about cabs sort of makes me giggle)*.


What sort of made me giggle were the arguments over the choice of the formulae and the results of math that is discussed.

Granted, there is much less in the way of physics involved with speaker cabs for guitar, but we (as guitarists) would also like to learn what is involved and what merits consideration in cab design, even if the design concepts are very basic in nature.

Cheers

Dave


----------



## washburned (Oct 13, 2006)

Got this off the Celestion website:

"Generally, open back or sealed boxes should be used.Open back gives a looser low end with less depth, and 'figure 8' directivity (sound field looks like an 8 when looked down on from above the cab). Sealed boxes give tight, deeper low end but are more directional, giving less spread of sound. Vented / tuned / ported / reflex boxes do not generally offer an advantage to lead guitar speaker operation. If such a loading is required. it is recommended that the alignment should be chosen with care as inappropriate reflex designs can cause speaker damage. The box size is not critical. The baffle size is more important in open back boxes (larger = more low/mid presence), and for closed back boxes larger volume means deeper but looser bass. Do not use internal acoustic wadding, it is inappropriate for guitar cabs, reducing sparkle and life."


----------

