sub woofer help

Archived from groups: rec.audio.tech (More info?)

Save yourself a lot of grief and work. Get one of the ones used for
automobiles. You can get a dual unit that will work very well, and they are
not very expensive.

--

JANA
_____


"Stu Pidassle" <massendo@yahoo.com> wrote in message
news:1122726703.754678.312590@g44g2000cwa.googlegroups.com...
I need a bit of help with a problem that I am struggling with. My wife
decided that the BA bookshelf speakers I had in the kitchen were too
big, so I replaced them with a set of the smallest Newton series from
Cambridge Soundworks. As you can imagine, the new set up complies with
the wife regulations, but does not have enough bass. I have roughly
4.5 inches under a cabinet to hide a sub woofer. I have been doing
some research into building my own sub, but all the excellent info that
I have found here is much more ambitious than what I have in mind.
What is the harm/benefit of finding a cheap subwoofer(s) (maybe even
auto) and building a box that fit the space vs. building an
accoustically correct subwoofer?

Thanks,
Stu

Archived from groups: rec.audio.tech (More info?)

Just exactly how much space do you have?

If you get a car sub woofer box, don't expect much. They are typically band
pass boxes and are more for rattling the body panels than for sound quality.

If you are looking to put some low end into a tight spot, consider isobaric
coupled 8 inch woofers. There are some that have dual voice coils, although
I don't believe in that sort of thing.

The nice thing about isobaric coupling is that the box volume is cut in
half. If you don't need to look at the pretty woofer cones, clam shell them
together on either side of the baffle, and save lots of space and grief.

Do you know anything about putting a woofer in a box?

http://www.akrobiz.com/speakers/

~James. )


"Stu Pidassle" <massendo@yahoo.com> wrote in message
news:1122726703.754678.312590@g44g2000cwa.googlegroups.com...
> I need a bit of help with a problem that I am struggling with. My wife
> decided that the BA bookshelf speakers I had in the kitchen were too
> big, so I replaced them with a set of the smallest Newton series from
> Cambridge Soundworks. As you can imagine, the new set up complies with
> the wife regulations, but does not have enough bass. I have roughly
> 4.5 inches under a cabinet to hide a sub woofer. I have been doing
> some research into building my own sub, but all the excellent info that
> I have found here is much more ambitious than what I have in mind.
> What is the harm/benefit of finding a cheap subwoofer(s) (maybe even
> auto) and building a box that fit the space vs. building an
> accoustically correct subwoofer?
>
> Thanks,
> Stu
>

Archived from groups: rec.audio.tech (More info?)

Well, believe it or not, Radio Shack isn't the worst place in the world to
look for stuff. But it's not the best either. Try looking at MCM Electronics
(http://www.mcmelectronics.com).

If you cut a hole in a board that is about the same size as the woofer cone,
you can mount a woofer on both sides of the board so they look sort of like
a clam shell. They both have to be exactly the same kind of woofer. Then you
wire the two woofers out of phase so that the signal going to them causes
them to move opposite of each other. Since they are front to front, when one
moves in the other moves out, so they compliment each other. It looks a
little weird to see the back of a woofer on the outside of a box, but it
works! This has the effect of doubling the mass of the moving system and
doubling the spring factor of the suspension. It also adds a little bit of
mass of the air trapped between the cones. What you end up with is a system
that requires only half of the cabinet volume that would have been required
for just one of the woofers alone. You can design either a sealed or a
ported box this way. If you have no way to measure the specs of the woofer
you want to use, then just go with the rated specs of one of the woofers and
cut the Vas in half. Do you have any books on speaker design?

~James. )


"Stu Pidassle" <massendo@yahoo.com> wrote in message
news:1122943240.295069.172120@f14g2000cwb.googlegroups.com...
> James,
> I have never built my own speakers, but I have a decent set of tools
> and basic experiencing fabricating things from wood. I have a spot
> roughly 2' deep x 4' long by 4.5" high to hide my subwoofer. If left
> to my own devices I plan on finding a DVC driver and some form of cross
> over and building a bottom firing box to fit the space. What I can't
> figure out from your site is how this arrangement would work. Two
> woofers firing at each other from opposite ends of the box? Two
> woofers front to back pointing the same direction? Would I need to
> create a port in the box? Do you have a source for your parts? All
> help is appreciated, I plan on stopping at Radio Shack tomorrow to see
> what they have in their parts bin.
>
> Thanks,
> Stu
>