Well I decided that it is time I invest in a high quality, high output sub that reaches very low to be used as my reference sub.

Being the cheap bastard that I am I have decided on a DIY sub. I have found a great package at www.solen.ca using a peerless 12", 2 passive rads, and a 500w @ 4ohm plate amp.

The package is a modified kit based on this: http://www.solen.ca/sxls12.htm
I am going to use a beefeir sub, 2 rads instead of one and upgrade the amp to more power and it includes an eq. All recomended by Solen.

Now I have never built a passive rad sub before, and I do have a basic grasp of the workings of such a system, however my cheepness is nagging at me.

Is it worth the extra $250 it will cost in passive rads instead of using ports?

Keep in mind that the end goals of this sub is to be a reference sub that I can test other subs against, and one that can achive high spls at 20Hz.

 

so you buy this kit that includes that includes a sub and plate amp and you build a box for it? i doubt it will have the low end your looking for.

i suggest you buy a quality sub with a lower fs somewhere around the 25 hz region and then put it in an box thats designed to play low and loud. quarter wave transmission line

 

would this work
a pc's psu that would give power to a car amp to a car sub in a box in your home .does it work ? if not, why?

does a home set up run at 8oms ?
how can i get 4oms so i can use all the speakers that i have form my last car

 

The sub in the kit has a FS of 18Hz.

Dukk, going from a Pasive Rad design to a Ported design, I should be able to keep the internal volume the same and still have the low tunning freq right?

 

Hmm I'm in the same boat as you Been debating on building a DIY sealed sub for music, or buying a premade kit. I alread have an external amp to use, but I would want an active crossover to adjustment + sub and MDF for box.

 

Running the box numbers I get this:
http://www.the12volt.com/caraudio/boxcalcs.asp#por
Vb - 1.59ft^3 (44.9L)
Fb - 20Hz
Port D - 4"
Port L - 50.3"

A 50 " port is a little long IMO.

Doubling the box size brings me to
Vb - 3.18ft^3
Port D - 4"
Port L - 23.69"

Still long...

Vb - 4.5ft^3
Port D - 4"
Port L - 15.8"

So, I could use two passive rads at an extra cost of $250 and build a 1.59ft^3 box...or build a 4.5ft^3 box with ports...

 

But what about length (as Jrace just found out)

The reason for using passive radiators is when porting is impossible due to port length vs enclosure size.

Jrace, what did the response look like at 4.5ft3 ?? Vs's the 1.6ft3?
Also if the PR design used 2, you better go to a 6" port (or 2: 3") at minimum. That will make the port length even harder.

What sub are you using anyway?

[ December 28, 2005, 06:19 PM: Message edited by: chev2 ]