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-   -   Enclosures for Eminence Sigma 18" and/or Eminence Kilomax 15", PA-sub application (http://www.diyaudio.com/forums/subwoofers/61774-enclosures-eminence-sigma-18-eminence-kilomax-15-pa-sub-application.html)

esaias 2nd August 2005 09:03 AM

Enclosures for Eminence Sigma 18" and/or Eminence Kilomax 15", PA-sub application
 
Hello!

I have pair of Sigma 18" and a pair of Kilomax 15" and I (we) need new subwoofers for our PA system.

The sub needs to be loud and longthrow. And preferably compact in size to make handling/rigging more easier.

I have been trying to look for enclosure designs but haven't been able to find any drawings, just some few numbers.

Is there any readily availeable drawings of cabinets that use kilomax or sigma?

I can build stuff from drawings but I don't dare to start design such stuff from scratch.

Thanks!

-Tomi

rcw 4th August 2005 08:01 AM

re boxes
 
From its specs the Sigma 18 is most suited for horn loading.
There are numerous designs for scoop bins that should suite.
The kilomax is optimum in a filter assisted QB5 alignment, otherwise its full power handling capacity cannot be used, this will have a f3 in the 60-80 Hz. region.

Rademakers 4th August 2005 04:14 PM

Quote:

Is there any readily availeable drawings of cabinets that use kilomax or sigma?
Not that I know.

Both speakers are suited for bassreflex application. Hence this will give compact designs. The electrical powerhandling of the Kilomax 15" won't be reached by far in a typical PA bassreflex enclosure. But then again it won't need to do so.

Designing bassreflex really isn't that hard. You can always download WinISD Pro and use this for doing it right.

For unanswered questions and second opinions you could always get back to the forum.

Mvg Johan

rcw 5th August 2005 12:16 AM

re sigma 18
 
It is true you can reflex load the Sigma, but you can't get any worthwhile bass much lower than 60Hz. from it because its xmax. is small, and its Vas is large, indicating that it is intended to drive scoop bins.
The general idea for mobile sound reinforcement is that if you don't use the full voice coil rating and excursion capability of the drivers then what you are hauling about is too large and takes up to much space.

norty303 5th August 2005 03:04 PM

You're trying to do the impossible i'm afraid, and with a driver that isn't the best to begin with.

There's not really such a thing as long throw as far as subs are concerned (go to ProSoundWeb and read the thread there, its too long to reproduce here) and a scoop bin is not the greatest design for most applications due to the timing issues, leaving a wooly sound. In order to go low with a horn you can do a number of things, most requiring a large mouth area either from a single cab or more commonly stacked multiples.

As you can see, this doesn't really fit with your 'compact' requirement.

Can I suggest popping over to the speakerplans.com forum where this is an everyday question and people in the know can give you some good advice. Personally, I'd be considering selling the drivers you do have and buying some Ciare 12.00 to put into some Punisher horns. Not the easiest build but incredible output from the 12" driver. Only problem is its a true sub really only useable up to 90-100hz so your bass/midbass speakers will need to be able to play down that far convincingly.

And if you're after plans there are many good ones at speakerplans.com too

Rademakers 8th August 2005 03:11 PM

Quote:

It is true you can reflex load the Sigma, but you can't get any worthwhile bass much lower than 60Hz. from it because its xmax. is small, and its Vas is large, indicating that it is intended to drive scoop bins.
That's also a way to see it. Vas is highish indeed.

I got down to about 40 Hz (f6-ish), that's all you need for most types of music. However, it's an typical Eminence driver with it's small Xmax and of course the lowest in series, so you should expect a powerdip anyways.
But I think it could handle 500 Watts in practice and that would be enough.

Tho I would rather sell all 4 and setlle with good 18"/15". A Qts of around 0.3 is pretty typical for a good 18"basreflex for PA use btw.

Mvg Johan

rcw 8th August 2005 11:57 PM

sigma
 
The Sigma is very much like the 70's JBL drivers like the e140 and k151.
These are designed for horn loading, and in the case of the e140 it could also be used for mid bass and in foldback boxes.
If you are into retro then the sigma might be o.k. in a 4518, horn/reflex "Keele box", but in the modern p.a. context these are too large since power has become a lot cheaper and the filter assisted reflex boxes give better bass for space.

esaias 9th August 2005 01:01 PM

Thanks a lot for helping me out!

I think we're going for BillFitzMaurice Tuba36 wich seemed quite interesting although the horn enclosure is much more complicate to build.

These are for Kilomax 15"s

Is this a good idea or do you know a better alternative? :)


-Tomi

rcw 10th August 2005 05:17 AM

re tuba 36
 
I would not use one myself since in a typical free standing live situation you need to group at least 4 of them to get enough mouth area to go down to 40Hz. with any accuracy.
Overall the bass extension you want is the critical question, 60Hz. is easy and most common 40Hz. is better and a little harder.
Anything below 40Hz. has always been looked at as a bit of a luxury because costs size etc. really start to blow out.
The classical rock/r&b sound was brought about by 60Hz. "w" boxes.
If you take the exact approach..
1.) Find out the volume of the venues you will be playing.
2.) find out how much transportation volume you have and/or can afford.
3.) The music you play determines how loud and how low.
The last is important because both of the drivers you mention are optimised for 60Hz. "punch" region bass output that is typical of the classic rock/r&b sound.
You can go lower with them but they are not optimum since you will be driving them well beyond the linear excursion limit and that is not good for reliabilty.


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