PA Subwoofer

[dangus]

Take a look at Speakerplans.com

Horns are big, but you get more boom for your amp watt. Also consider bandpass, and of course tapped horns which are a lot simpler to build than those folded horns.

[nigelwright7557]

By the time you have bought the wood, screws, cabinet corners, jack sockets, castors, grill, grill clamps etc etc you are getting close to the cost of a ready made speaker box.
There is also the time and effort and making sure you have the right tools for the job.

I build my own enclosures but more to get a loudspeaker box I want. For example I wanted 2 boxes each with 2 off full range 12 inch loudspeakers in them. I used the Eminence 12 beta LT which are full range speakers.

I also wanted a subwoofer so built a box with an 18 inch speaker in it.

If your needs are for a common speaker box then it is probably as hceap to just buy one ready made.

[technofreak]

Originally posted by nigelwright7557
By the time you have bought the wood, screws, cabinet corners, jack sockets, castors, grill, grill clamps etc etc you are getting close to the cost of a ready made speaker box.
There is also the time and effort and making sure you have the right tools for the job.

I build my own enclosures but more to get a loudspeaker box I want. For example I wanted 2 boxes each with 2 off full range 12 inch loudspeakers in them. I used the Eminence 12 beta LT which are full range speakers.

I also wanted a subwoofer so built a box with an 18 inch speaker in it.

If your needs are for a common speaker box then it is probably as hceap to just buy one ready made.

I agree. Due to economy going south here I have given up an Eminence Alpha 6 midhorn idea (which would cost me around 200€ for horns alone) for time being and instead put them in small sealed boxes. So far total cost around 130€. For that price I could have bought for example these boxes.

But the plus side is I know my speakers thoroughly, I know what components exactly are used and, thanks to published data for Alpha 6 and, more importantly, learning from other people's experience w/ those speaker drivers I knew before building them that they will sound good. But of course, this does not apply if you can actually listen to speakers before buying.

[zoranaudio]

Originally posted by Rademakers
A single one of these would suit your purposes, loaded with an Eminence Kappa 15LF. One sheet MDF for about £15 and driver for £125 leaves you with enough room for cables and a nice finish. Of course Baltic birch is got to be prefered over MDF for on the road purposes.



Here is quite similar type of box, I made long time ago and using for home loud listening

[jaya000]

Rademakers,

Nice drawing!
Which software u used for 3D drawing?

I think ur cabinets can be used for 18" with little modification.

[Rademakers]

@Zoran, it looks like it's about 250 litres (50 x 50 x 100 cm) am I right/close? That's about the same volume as mine. High EBP drivers like the 15PK40 don't simulate very well but sound suprisingly good, I think that the high Fs is perfect for your design.

For me this is the third prototype. The earlier prototype had a longer horn path and smaller rear chamber, also made a front loaded BPH with the same volume for comparison. On sheer output and percieved low frequency response the front loaded BPH lost completely.

@Jaya: Thanks, it's done in Solidworks, I asked a friendly forum member to help.

The original was designed for 18" drivers. That particular cabinet is 65 cm deep instead of 62 cm, see the drawing on the right. The extra 3 cm allowes for the 18" to comfortably fit on the baffle. Both can be made from exactly one sheet (including bracing).



Regards Johan

[zoranaudio]

[QUOTE]Originally posted by Rademakers
[B]@Zoran, it looks like it's about 250 litres (50 x 50 x 100 cm) am I right/close? That's about the same volume as mine. High EBP drivers like the 15PK40 don't simulate very well but sound suprisingly good, I think that the high Fs is perfect for your design.

Hi!
Now just took the measurements of my box and they are:91cm height, 55 cm wide, 60cm deep.
I cloned this measurements from some commercial PA box, I don't know which brand was.
Maybe my dimensions not exactly much original dimensions but they are very close perhaps 1 or two more or less.
Is this design of box called HORN or I am wrong???
Also here in my city I saw similar but twice longer and twice less of height with two woofers inside and they can not be seen from the outside, just "horns from both left and right"
Did you see this kind of box and do you have any dimensions for 15" woofers or??/
Is it any mathematic's for this kind of boxes.
BTW I never measured tmy PA woofer, but according to my ears it sounds well and (hard and well defined bass, fast) but not so deep minimum freq, according to my ears this reproduces about 35 HZ, and other box which is on the bottom on the floor use Pioneer 12" woofer with big rubber suspension, vented magnet and covered with plastic, I think the model was TSW 1200C.
This reproduces vibrations which is bad for the health , I think minimum 20 HZ perhaps less, never measured!

[zoranaudio]

Here is another picture, just for sense of dimension, I am 185 cm tall and 120 kg body weight!

[Rademakers]

Is this design of box called HORN or I am wrong???

It's a horn, tho it's usually called a hybrid (between horn and bas reflex). Because of the driver location it can also be seen as a tapped horn with chamber.

Also here in my city I saw similar but twice longer and twice less of height with two woofers inside and they can not be seen from the outside, just "horns from both left and right" Did you see this kind of box and do you have any dimensions for 15" woofers or??/

That's a vague description, that sounds kinda like a double front loaded BPH, like there are many.

Is it any mathematic's for this kind of boxes.

My prototypes showed easily predictable (in general performance)when compared with a rear loaded horn. However the driver location is thought to have a special influence not seen in the simulations.

Regards Johan

[zoranaudio]

Great Rademakers!
Thank's for the description, I remind Mr. V. Filevski (audio scientist from Skopje) who measured all my speakers and designed crossovers for them except the sub-woofers, told me the same that this box is a hybrid like you said.
I don't have loaded any damping material inside box, should I put some???
I have put some damping material from the outside except the bottom and upper side of the box(some kind of rock or mineral wood, which is used in house thermal and sound isolation) and covered with some synthetic material like final layer, like on the picture.
Regards!