How to make high output subwoofer?

[Ric_LV]

Hello!

I am a mobile DJ and I am fed up with renting the subwoofer for my events. I want to build one for my own. I got a great deal for a pair of Eminence 18" woofers ( http://www.usspeaker.com/SigmaPro-18-1.htm ), I got them basically for free, brand new... Anyway, now I have the speakers, but how do I create the subwoofer box? What type of box gives the loudest bass? Let's say, I don't need no super-lows, just something above 30 or 35 Hz. Something simple, but efficient. And one more thing, I am a newbie. Can you help?

[richie00boy]

Big vented box for those babies. Download yourself a copy of WinISD Pro and have a play with some designs.

[nunayafb]

Start by downloading winisd pro from there website, its free.
Obtain the thiele/small parameters from the link you posted, and you can model the woofers in the program. Model the woofers in sealed, ported, 4th and 6th order bandpass, note the excursion of each type, the max spl, group delay and the box size required. The EBP will determine the recommended box type, see winisd help file for explanation on that.

The simplest to build and tune is the first one I mentioned, they get bigger, louder and harder to tune as the list progresses. There is more to it than that but a quick search on each type will get you a ton of important info to clarify the differences.

I am deliberately not giving you too much info because you will learn more and benefit more from searching on specific problems that come up rather than someone paraphrasing it all in this post. So as you progress and learn more you will be able to ask more specific questions. IF you want to stick with this hobby do the above or...

You might be able to search and find someone else who has done something with these drivers before, and you will definately find someone who has built some stage woofers before, search for this if you want a quick "cookbook" style design.

[bob123]

Learn about bass horns and bang them in one of them!!!! Will make the crowd die. The main problems is that the horn is generaly quite big for frequencys down to 35hz and far more complicated to build. But can increase the spl by 15db
(thats 10/\1.5 times more efficient)

Or you could go for the bass reflex option. I have done that and found a need for horns as the power needed to get a decent amount of bass is a bit silly (bass reflex are about 1% efficent where as horns can be up to 60%)

It all depends on your woodworking skills and amount of time you have. If you want to put the effort in go for the horns they are well worth the effort!

http://www.speakerplans.com/index.php?id=1850horn
http://www.speakerplans.com/index.php?id=186horn

[diycoax]

Originally posted by Ric_LV
Hello!

I am a mobile DJ and I am fed up with renting the subwoofer for my events. I want to build one for my own. I got a great deal for a pair of Eminence 18" woofers ( http://www.usspeaker.com/SigmaPro-18-1.htm ), I got them basically for free, brand new... Anyway, now I have the speakers, but how do I create the subwoofer box? What type of box gives the loudest bass? Let's say, I don't need no super-lows, just something above 30 or 35 Hz. Something simple, but efficient. And one more thing, I am a newbie. Can you help?

Hi,

You have a pair 18" woofers, you can use JBL 4642A cabinet...
My friend have two pair TAD TL1801, use two 4642A cabinet...

[Rademakers]

I don't need no super-lows, just something above 30 or 35 Hz.

For PA purpose that's already super-low. Highpass @ 40 -45 Hz or higher is more common for mobile DJ's.

If you're making a basreflex I would advise you to tune around 40 -45 Hz. Otherwise you'll find the Sigma's will run out of Xmax quite fast.

For higher efficiency use a Band Pass Horn to keep things transportable. Sensitivity is ussually raised up to 6 dB (definatly not 15 dB, that would be superb). Stack 2 together for more low end extension:

http://groups.msn.com/SpeakerBuildin...oto&PhotoID=19

With kind regards Johan

[chops]

From the looks and sound of it, I think Ric LV is wanting/needing something rather quickly and simple with good results.

With that in mind, I would recommend a simple ported enclosure of 8 cubic feet tuned to 45hz, both drivers in one enclosure and with two 6" ports 5" long each.

This is a simple design and will get you and your sub out on the road ASAP.

[Ric_LV]

Thank you all for your replies... The are very useful.. However my skills are low... Yes, I can make a good, cube-shaped box, but that's it... I think that if I will start to make horns, they will be made awfuly wrong and that would be just a waste of time. I will try to play with that software, you suggested. Thanx again!

[nunayafb]

diycoax, and anyone else who goes mobile with their own equipment is that monster subwoofer actually considered portable?

Wow, how normal is that sized sub?

[Rademakers]

For mobile DJ use one single sub a side is more common for maximum flexibility. There are metal bars available to put in a mounting hole which you can easily incorporate in the sub. You can put the tops on the needed height on the other side of the bar, with or without safety. This also eliminates the need for special speaker stands. A single unit could be about 20-22" cubed.

Do you have filtering and amps for the sub?

Wkr Johan