PA Subwoofer

[suchuwato]

Hey guys,

I'm selling my guitar amp soon and that'll give me some cash to spend specifically, around £200 / $355

I've already got a pair of these:

Gemini gsm1580

Which aren't that great, I know, but they work (for the moment)
I also use some other gear that isn't mine, so I can't link to it at the moment...

I normally play stuff ranging from House to Hip Hop, pretty much anything.

I'd like to build a subwoofer, as there's no way I can afford to buy a decent one for my budget. Initially I was thinking that I could get a couple of 12" subs designed for cars (JBL or something) and build the boxes (as there's plenty of plans floating about), but then again, these will be for small-medium sized rooms, not cars.

As you may have guessed, sound quality isn't the most important factor, although I don't want it to sound like the sort of thing you hear coming from the back of a chav's Nova

So I guess I'm asking, how much power can I get for £150, leaving £50 to build the box(es?) and get cables etc...

I'm not factoring an Amp into this budget.

Thanks in advance!

 

[technofreak]

Hi,

I quess that Eminence Kappa 15 LF in a 150 L box tuned to 45 Hz would be good solution. Later upgrade your mid-tops to, for example 2x8" + 1" box (Eminence Beta8 is quite qood option for 8" midrange), or even 12" or 15" midbass + 6" horn-loaded cone + 1" and add another sub, and you can hold parties for a few hundred people w/ ease

 

[suchuwato]

Thanks for the reply. I've been looking at this box, any opinions on it? Also would that eminence driver be suited to it, or any other suggestions?

http://www.bcspeakers.com/index.php?sez=3&categoria=45&prodotto=110

 

[Zero Cool]

If you can find the Yamaha SW118V subwoofers. thats a lot of boom for the buck. Cast frame Eminence 18" woofer with high power handling, a low FS and a large X-max these are a pretty good buy for the money. these are pretty cheap new at $399 each and used, even cheaper. the only issues is the woofer is so powerful, it blows the bracing apart inside. many of these used will make horrendous farting sounds. good to talk the seller down point. But a little wood glue and some screws and they are like new. and will play very deep.

These sell for $150-200each USD im sure you can find them over there just as cheap.

Zc

 

[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.





Regards Johan

 

[jbell]

That eminence driver is a good one, however,
Can you point me to a measured and/or calculated 2pi response for that cab?

I know I had to go much bigger to get the response I was looking for.

 

[Rademakers]

These are the excursion and SPL as predicted by Hornresp (2,83V/1m, 2pi), the grey line is the B&C SUB 15 (to which the Kappa 15 LF is indeed suited by the way).

An externally hosted image should be here but it was not working when we last tested it.

@jbell: What response are you looking for?

Regards Johan

 

[jbell]

Rademakers:
usually I go for 40hz, on up for pa subs, but each cabinet has it's plus/minus on size vs response.

What caught my eye, was the design you posted looks like you'd have to model it with a coupling chamber, and then a short L23.

Can you post the hornresp input params?

Also, how wide is that cabinet?

thanks

 

[tinitus]

Eminence Omega Pro 18 will cost you 134 english pound at Blue Aran UK
It will do pretty well in BR(bassreflex)
Delta Pro 18 is a bit cheaper at 94pound and may do fine too
Seems there is a little confusion about which model

At least they will get you a bit below 40hz

But only a few pounds more will buy you top notch english quality, Precision Devices...some bargains on archived 18" models

 

[Rademakers]

usually I go for 40hz, on up for pa subs, but each cabinet has it's plus/minus on size vs response.

I found this cabinet sounds deeper as it goes, if there's such a thing.

Can you post the hornresp input params?

Not yet, will soon.

Also, how wide is that cabinet?

The 15" version is 62 cm cubed.

Regards Johan

 

[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]

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]

@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!