AS112A and AX84 1x12 cabinet build issues speaker protection

[Zappacat]

I've got both of these speaker cabinets on the drawing board right now :

AX84 1 x 12" Speaker Enclosure

AS112A Plans

I have one of them (AS112A) about half way through assembly and I realized there won't be any space between the front edge of the speaker(once installed) and the front of the speaker cabinet itself.  This leaves me with no room for putting a protective screen or something in front of the speaker unless the protective screen/shield extends beyond the front of the speaker.  Am I missing something here?

What do you guys use for protective speaker mesh / screen ?

I realize at this point that a simple solution to this is to increase the depth of the cabinet box so I can inset the speaker mounting position more but I've already cut the wood and from my understanding these cabinets are designed so that the internal cabinet volume/area is critical to the way they sound.

Thanks in advance.

[tonyharker]

Are you mounting the speakers on the front of the baffle or on the rear.
I normally mount them on the rear so that the speaker cloth/grille fits flush with the front face of the baffle board. 
Alternatively you can rebate around the speaker hole, so that the speaker is inset.

Regards  Tony.

[Zappacat]

I can't believe I didn't consider that.  After I read your post I started looking at some of the amps I have around the house and noticed they were ALL mounted behind the baffle board.  For some reason I had it in my mind they should be mounted on the front side.  Guess I would have known if I had taken the speaker out of the box and seen the mounting gaskets on the front side of the speaker.  Thanks for pointing out the obvious to me.  I guess I get the Beavis and Butthead award for the month.  Possibly the year.

Anyone know of a protective grille mesh I can pick up at home depot or lowes that's suitable for this application?

[J M Fahey]

If your option is Home Depot or a hardware store, there is that black open mesh cloth that's used to make a sun shade over delicate vegetables.
We call it "media sombra" (literally: half shadow) because it lets some Sun shine through.
It's saved my bacon more than once.
The mosquito-screen type is too rigid and makes for ugly bends.
You staple it to the front board, hiding the staples on the sides or back, just copy Fender and others.
On home decoration shops you will find beautiful curtain-type cloth, just try to look through it and balance transparency vs. strength.
You just won't find it in black.
At least I can't , and people stare at me and whisper to each other "satanist".

[phatt]

Hello Zappacat,
There is no magic size it's not the space shuttle the word you need to concentrate on is *ABOUT* this wide *About* this deep.

You only need to look at the massive variations in what has gone before.

Guitar speakers are low compliance drivers and as such do not depend on box size.
If this where not so then every open back guitar amp combo on the planet would sound horrorbillus.

Close the back of the cab and the sound will tighten and focus a little more.

So moving the front panel in by 3/4 inch will not effect the sound.

Speaker cloth should not lay flat on the baffle board,, you need to raise it slightly off the board as the cloth will flap againt the board.
You need to put a small moulding all the way round the front outer edge.
see drawing.

Cheers, Phil.

[Enzo]

Or bolt one of these things over the cone.  They come in all sizes.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-373

And if the grille projects beyond the front edge a little, what harm?

[Zappacat]

Hello Zappacat,
There is no magic size it's not the space shuttle the word you need to concentrate on is *ABOUT* this wide *About* this deep.

You only need to look at the massive variations in what has gone before.

Guitar speakers are low compliance drivers and as such do not depend on box size.
If this where not so then every open back guitar amp combo on the planet would sound horrorbillus.

Close the back of the cab and the sound will tighten and focus a little more.

So moving the front panel in by 3/4 inch will not effect the sound.

Speaker cloth should not lay flat on the baffle board,, you need to raise it slightly off the board as the cloth will flap againt the board.
You need to put a small moulding all the way round the front outer edge.
see drawing.

Cheers, Phil.

I'm confused, many of the guitar amp speaker enclosures I see on the web say not to alter or scale the dimensions due to the fact they've run it through some sonic simulation software during the design process and determined what the dimensions should optimally be.  Even down to the point of making internal bracing schemes exactly to their specs so not to interfere with the internal volume(in terms of space) in the enclosure.

Also, the AX84 speaker planshttp://ax84.com/static/corecabinets/AX84_1x12_Cab_09.08.03.pdf even instructs you to drill different size ports in the back of the speaker cabinet based on what tuning you generally use.

Can anyone enlighten me on this?

What's a good simple speaker enclosure to build just for someone starting out?  I'd like to be able to experiment with it open vs. closed back.  I don't want it to be heavy but If it's better for the sound to use more dense wood then I could deal with that.

Thanks in advance.

[phatt]

OK, look if you want to believe  in Hi teck then do as they say it's your amp after all.
In all My Years Of Experience I've never had issues with such *TRIPE*

Yes I spose if you wish to disect every last dB from a box you can run a wacky sim on it if you must.
Keep in mind the Marshall Simulation Experiment:)
Jim Marshall designed Built by this amazing bit of computer called the *Brain*.

It's called the economy and cost simulation (and you don't even need a conputter:)

Take x number of boards from a supplier and work out the most amount of boxes you can get out of one sheet of board.

Sounded good emough to make his Amplifiers *World Famous*

Ports only work below 100Hz and can make things rather peaky and thats just with HiFi woffers. Now take a guitar speaker which has freq response all over the place and it's anyones guess as what it will sound like.

The bottom string on your guitar is 82 Hz  and you want extra bass
Then go buy a bass guitar and a bass amp.
The problem with this modern world is everything has to be hi-teck and specialized and made to sound vastly complex and the simple truth is it's NOT.

If you want better Bottom end then tweak the Amp.
Phil.

[rowdy_riemer]

I have to agree with you, phatt; I don't think there is a need to over-engineer a speaker cab. I've got a MOD-8 in a sh*$tty old school intercom speaker box, and I'm surprised by how much low-end it has, UNLESS, I plug my ValveKing Royal 8 into it. But the ValveKing Royal 8 has crappy low end regardless of what I plug it into (I've got a fix for that on the way). There are some general things to do to tweak the sound a speaker cab, but don't worry about exact placement of anything. Then again, I don't exactly have a lot of experience building speaker cabs, so maybe I'm full of crap.

[J M Fahey]

many of the guitar amp speaker enclosures I see on the web say not to alter or scale the dimensions due to the fact they've run it through some sonic simulation software during the design process and determined what the dimensions should optimally be.

Thanks God it ain't so.

[bry melvin]

re speaker at very front of cab
mount the speaker on the back of the baffle

use a tone ring  (sets the speaker back)

as far as dimensions... it makes little difference unless you calculate ALL the specifics of the speaker used....use a replacement later and it's all for nought.

and yes the original marshall cabs didn't take ANY of this into account. Nor any of the fender showman amps etc etc.

if closed back the ports should be ~ 1/2 the speaker area...diameter (or of  a size that equals the area of a round hole half the speaker diameter if rectangular) that's so you don't get wind noise...not for exotic physics.

Also if you're sealing the cab...SEAL with calk liquid nails etc  again wind noise...  oh and stuff them about half full of insulation.  need more power for sealed cabs though....not for AX84

[Zappacat]

re speaker at very front of cab
mount the speaker on the back of the baffle

use a tone ring  (sets the speaker back)

Tone ring?  Can you elaborate on this a little.  What material do you make it out of?  Dimensions?

[bry melvin]

tone ring link:

http://www.mojotone.com/amp-parts/Hardware/Mojo-12-Tone-Ring


A tone ring setup will place the speaker flush with the front of the cabinet...not protruding, but still could have front access for mounting. Very useful on tweed deluxe type cabinets etc. Don;t have to remove amp to get at speaker.   speaker is mounted on the tone ring which is mounted on a second partial baffle.. hard to describe see pics in link.

[phatt]

Notice the use of the Word *TONE* to describe a simple metal recess ring.
Then also notice the Word *MOJO* to better describe it's scientificly proven quality.

Excuse me while I step out and throw up.
Phil.

[bry melvin]

actually mojotone provides some pretty good kits for repro fenders

the POINT of a tone ring (disregarding hype) is  for an old tweed copy where the chassis hangs down the back...it allows you to velcro the grill ala peavey and r&r the speaker without dismantling the amp...Convenient when making "tweed" "copies"

However that supplier is a bit steep for something you can make with a 4 foot brake and a wire welder  

But it did provide a convenient picture.