speaker boxes.

N

Nick_Black

Mirthmaker
a while back I saw someone build insolated boxes to put thier cabs in to mic, saving the effort of acustifying the whole room. anyone have a link to how to make them, or a link to a page about them? (if you know what I'm talking about..)

thxs :)

cheers

Nick_Black
 
Why not just put a couple absorption panels infront of the amp? Or are you looking for isolation? If so, just build a box within a box(decoupled) like you would a room...
 
thxs for the reply's, :)

yeah, the box inside a box is what I had in mind, (similar to the link that Guitarer gave me, only the box can hold any cab you wish to put in it.)

perhaps I'll build my own design and post it up..

cheers :)

and again, thxs for the reply's.
 
what about a 4'x4'x4'(cube is shit for acoustics though) box? It'll sound shite inside though, unless you make it really dead. But you also gotta think about bass frequencies. I'll draw something...

Right this is a plan view. You should have rigid fiberglass on the ceiling and could leave the floor reflective. It might also be better to fill the gaps between MDF, or drywall, with insulation, and maybe double thickness of whatever you choose. I'd personally build it in thick MDF or HDF. And for the floor, have it decoupled with neoprene sheet, or pucks.

This picture is missing a lot of detail, at the doors etc, You gotta make sure it's all sealed up. It might also be better to keep the amp outside if possible, as the heat will build up quickly. So you need to devise a way of getting the signal in, without sound escaping...

If you don't need isolation, then just build a couple of 2'x2'x4" panels and place them infront of the cab.
 

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yes, that's close to what I was thinking, only my Idea was even smaller (1mx1m) and since I have a hard time getting rigid fiberglass, I was thinking roxul instead. (mt parents do quite a bit of renavating so there's lots lying around) I wans't shure If I should leave the floor bare, I was thinking about going with a complete dead sound...

edit: actually I found a site for rigid fiberglass that'll ship to can. so I'll try that.
 
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ok this was my Idea, The iner box I was thinking about making cardboard, becouse of that it's rigid enough to give structual support, but soft enough to not couse to many reflections, the "rubber mat" is that rubbery stuff you find under your carpet, whic I find works great for reducing reflections.. your thoughts?

boxuo7.png
 
Nick_Black said:
yes, that's close to what I was thinking, only my Idea was even smaller (1mx1m) and since I have a hard time getting rigid fiberglass, I was thinking roxul instead. (mt parents do quite a bit of renavating so there's lots lying around) I wans't shure If I should leave the floor bare, I was thinking about going with a complete dead sound...

edit: actually I found a site for rigid fiberglass that'll ship to can. so I'll try that.
Click to expand...
roxul should be fine, as long as it is semi rigid.
 
Nick_Black said:
ok this was my Idea, The iner box I was thinking about making cardboard, becouse of that it's rigid enough to give structual support, but soft enough to not couse to many reflections, the "rubber mat" is that rubbery stuff you find under your carpet, whic I find works great for reducing reflections.. your thoughts?

boxuo7.png
Click to expand...
I like my idea better, haha (biased or what!?). Mine offers more isolation, mass - air - mass, and bass trapping... Also Why not just have the fibreglass, roxul, covered/held in place with fabric? Mine could be adapted to any size, so 1mx1m would be fine. I just suggested 4', because joiners usually work in 4' or 8', so everything you find is roughly those sizes(here anyway).

With mine, you could also fill the air gap with insulation if you have laods lying around anyway...
 
no it's not bias if you have taken both into consideration and such.. anyway's, I'm shure yours probably is better, it's more the fact that your explanation kinda confused me, (well, almost evrthing did.. acustics is not my strong point..:o)
anyways, could you explain your Idea without short forms and such? (why you have 3 difrent thicknesses of fiberglass and such.. that would be great if you could :)

hope it's not too much hassle.

Nick_Black
 
Another option is to build a box like the Demeter SCC-1. The iso box has a baffle in it to mount speakers on. There isn't a link right to the product, but it's on the Demeter site under the product tab section called "speaker cabinets".

http://www.demeteramps.com/
 
Nick_Black said:
no it's not bias if you have taken both into consideration and such.. anyway's, I'm shure yours probably is better, it's more the fact that your explanation kinda confused me, (well, almost evrthing did.. acustics is not my strong point..:o)
anyways, could you explain your Idea without short forms and such? (why you have 3 difrent thicknesses of fiberglass and such.. that would be great if you could :)

hope it's not too much hassle.

Nick_Black
Click to expand...
Ok, 3 thicknesses because you need something thick 4" for bass and you need a gap behind this(4" panel with a 2" gap will act like a 6" panel, ie absorb more bass), then you generally need 2" for the rest (to absorb well at mid-high frequencies, reducing reflections at these frequencies), and give enough space for the guitar cab. I recommended 1" because the door might not be strong enough to hold 2", and the 1" opposite to keep symmetry.

For isolation: You need mass and need seals(wherever air can go, so can sound). Also, the best sound isolation is a achieved by a two leaf structure, eg. a drywall stud wall, sheeted on both sides.

There are two forms of sound transmission, structural and airborne. It is much harder for sound to travel through air than a structure, and also much harder for airborne sound vibrations to vibrate a solid structure. So it is important to decouple the inner leaf, from the outer(and the sound source from the inner). This leaves only airborne transmission, which makes for better isolation.

The more mass you can get for the inner and outer leaves the better, as sound has more to move, and the bigger the gap between the two leaves the better...
 
boingoman said:
Another option is to build a box like the Demeter SCC-1. The iso box has a baffle in it to mount speakers on. There isn't a link right to the product, but it's on the Demeter site under the product tab section called "speaker cabinets".

http://www.demeteramps.com/
Click to expand...
Here you go: http://www.demeteramps.com/products/cabinets/ssc1.html (right click and choose copy shortcut)

That's similar to what i was suggesting, however mine will give a better bass response(that will probably sound boomy with the thin absorption), the option of which guitar cab or combo you wish you use, and probably better isolation(that looks awfully thin to have good isolation and any absorbent material.
 
ok, I was just thinking y not 3" all around (3" also obsorbs the mid-high frequencies does it not?)

and I supose a problem with the dool seal is thta you don't want to use to many solids for a seal.. but I think I got something for that (2 seals.. just like 2 walls)

thanks for bieng so patient with me thus far (crazy arogant teenager that I am :p)

but why do you have only one big ait pocket? y not on all sides?

Edit: oh yeah, I checked out that link, but I was hoping for a box that you could put in your own cab, instead of using a preinstalled speaker. thanks for the link though :)
 
pandamonk said:
That's similar to what i was suggesting, however mine will give a better bass response(that will probably sound boomy with the thin absorption), the option of which guitar cab or combo you wish you use, and probably better isolation(that looks awfully thin to have good isolation and any absorbent material.
Click to expand...

I would probably build something similar, not exact. I'd make the baffle removable so I could switch out speakers easily, maybe even have a few with speakers already mounted and some with holes and ports. ps Thanks I don't know why I didn't think of right-clicking :p.
 
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Nick_Black said:
ok, I was just thinking y not 3" all around (3" also obsorbs the mid-high frequencies does it not?)

and I supose a problem with the dool seal is thta you don't want to use to many solids for a seal.. but I think I got something for that (2 seals.. just like 2 walls)

thanks for bieng so patient with me thus far (crazy arogant teenager that I am :p)

but why do you have only one big ait pocket? y not on all sides?

Edit: oh yeah, I checked out that link, but I was hoping for a box that you could put in your own cab, instead of using a preinstalled speaker. thanks for the link though :)
Click to expand...
Well even better, 4" with air-gap all round. I only didn't suggest this because it will really reduce the space you have, and if you have a 4x12" cab it might not fit. Also, i doubt an MDF door could hold a 4" panel. And also, it might be better to have a thicker panel with more gap, than two panels with less gap.

A 4" panel works really well, in theory, down to 850hz, then it starts to tail off(although it can work well down to 250Hz), an 8" panel to 425Hz, and 12" 300Hz. A 4" panel, with a 4" gap can absorb similar to that of an 8" panel. Isn't not really recommended to have a gap of more than the thickness of the panel, so for 12", it should be 6" with 6" gap. It could be done with a 4" trap, but 6" will yield better results.

I'll explain how to calculate this: speed travels at roughly 340metres per sec. 20Hz has 20 waves a second, so the wavelength is 340/20=17m. The best absorption is at the quater wavelength, so the thickness needed to(theoretically) absorb well to 20Hz(lowest audible frequency) is 17/4=4.25m. You can also work the other way: Start with the thickness and work out the frequency. 340mps/0.1m(10cm, 4")=3400/4(quarter wavelength)=850Hz.

And don't worry, I'm a crazy arrogant teenager too :p:D
 
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