[Justin_D]

I'm thinking about doing this, if I convince my teacher who is quite liberal, for a school project.

Here is what I want to do, and this will be my first

--A "space conservative" sub: not necessarily Sunfire small, but small enough to be taken to college.
--Goes down to 20hz (or lower) accurately
--NOT BOOMY
--Probably a 12" Driver

I have a Velodyne CHT-12 right now. I could sell it, or combine it with this DIY.

Is this going to be beyond my scope? How much is this going to cost? Can you suggest some amps and drivers?

[Travis Cain]

It might be better if you told us how much you're willing to spend rather than ask us how much it will cost. It would also help if we knew when you would have to have it done by. I'll assume you're looking for "bang for the buck"..

That said, for an amp I would suggest a 250 watt plate amp from http://www.partsexpress.com which go for $128. If you have a couple months before your project needs to be done, it might be worth waiting to buy it as it goes on sale quite often..

For 12" drivers, I would suggest an Adire Audio Shiva, however they were just "revamped" to Mk IV and are currently out of stock until next month I think. They go for $125. One of the great things about the Shiva is that Adire offers several different box designs depending on what kind of sound you're looking for so you don't have to do the work of making the calculations. Since you're looking for that sweet 20hz, perhaps an Adire alignment ported design might work out for you as it's less than 20" cubed so you should be able to bring it to school although it'll be pretty heavy. You can find more info about the Shiva and it's box variations at http://www.adireaudio.com

If waiting for the Shiva doesn't work out for when you need your project completed, another option would be the Dayton 12" Titanic Mk III for $160 at partsexpress.com but if you chose that route you'd have to design the box yourself. It's not incredibly difficult to do, but it will take a little time and researching.

As it's your first creation I would lean towards the Shiva as the box designing and blueprints are done for you. And as it's a really popular driver in this forum you might be able to pick up a used one and save a few bucks..


There is certainly a ton of other drivers & amps that can make outstanding subs.. But you'll be hard pressed to find better value per dollar IMHO..

[Ryan T]

If your going for a small sub that can go down to 20 Hz and lower your going to need a very powerful amp and a LT circuit. You'll also need a nice high excursion driver that can take lot of power (maybe an AV12?) to hit the lower notes with any authority. The more you can increase the size of the enclosure the less power you need to get the driver going. That one of the trade offs of small enclosures.



Ryan

[Justin_D]

Thanks alot Travis!
That was very informative. I have been looking @ Shivas before you even mentioned them. I was very unsure about amping it though. $400 would be the prefered maximum. I can wait. I may just do it for me, myself, and I. Screw school and their time limits! I wanna be able to take my time so I don't make TOO many mistakes. I like how w/ the MKIV I don't have to design my own box. I don't think I'm ready for THAT yet. Do you know any websites other than diysubwoofers.org that are good the inform me of the task ahead?

Put this 12" driver in a 1 cu^ft sealed box and give it about 300 watts minimum

[Justin_D]

I have no idea what sub that is...

[Justin_D]

I am now torn between the Tempest and the MkIV. I like that the MkIV is smaller, but I think the Tempest would really kick it into high gear when it comes to the bottom end. I know I'm probably getting into the territory of "not movable" stuff, but couldn't I just build the Tempest into a simple cyllindar design w/ a port similar to Warrick's sub? Obviously costs have gone down since he bought his!

I am also curious. Would this 250 watt plate amp be enough to power a monster like the Tempest?

I'll just keep editing this post :-) The more I look, the more I like the look, size, and simplicity of a of a cylendar sub w/ a port on top. Would there be a passive radiator involved? Do I HAVE to have it? Is it optional? Would it be worth it?

[Ryan T]

how much power will be enough depends on the enclosure size and if its vented or sealed. I have my tempest in a huge vented enclosure and 250 watts is plenty to bottom out the driver. But if i go put that amp on my 25 Liter sealed shiva I cant get it very close to Xmax.

What size enclosure are you looking at? I would say definatly go for the tempest if you can live with the large enclosure. I've messed with bot hsubs (well my shiva was a MkIII) and the tempest really does have a lot more power in the low end. Thats not to say the shiva is a slouch by any means its just it doesnt shake the room witth the same authority as the tempest does.


Ryan

[Ryan T]

Quote:

I'll just keep editing this post :-) The more I look, the more I like the look, size, and simplicity of a of a cylendar sub w/ a port on top. Would there be a passive radiator involved? Do I HAVE to have it? Is it optional? Would it be worth it?

If you are porting the sub you will not be using a passive radiator. a passive radiator cannot be down or up fireing it has the be mounted verticaly so unless you lay the sub on its side you cant use a passive radiator well you could spend a lot of time mounting one on the side...

My tempest i have now is a monster. You wouldnt be able to move it unless you had two people. Here are a few real quick pics. The top left is the sub without the sock over it, top right is with sock and in my bedroom/listening room, last pic on bottom is the top endcap with the port.

http://www.geocities.com/ryatod/tempest.html

I've gotten very good results in terms of output with my really tiny shiva. Its 25 liters as i mentioned above. The external dimensions are about 13"x13"x13". With that size enclosure its pretty portable but you'll loose everything below 36 Hz or so unless you make a LT circuit. The other draw back is it takes a TON of power. The enclosure is so small that it takes a lot to compress and decompress the air. The LT circuit would only make the power consumtion worse but you would get the last octaves back.


Ryan

[Wayne Ernst]

The driver that Jim posted a picture of is from Elemental Designs, runs $270 and can be found at the following site:
Nice Driver


** I have to admit, I knew nothing about this driver before Jim posted the picture. However, I looked at the properties for the picture, and found the source where it was located - then back-tracked to the Elemental Web site.

Enjoy!

[Allen Ross]

Justin, nothing is too big to move when it comes to subs, If i had the cash i would build a another 9 cuft tempest for my dorm, i still got some closet space. The best investment i ever did was the 17 bucks i have spent on the casters, it makes it so nice.

[Wayne Ernst]

Quote:

Jus