help on building floorstanding speakers

[sr2002]

helo guys,

i am kinda new to buildin speakers. i have recently built a lm3886 bridge stereo gain clone, and an opa541 mono sub amp to power the sub that i built that has two 6.5" drivers.

i am planin to build a pair of floorstanding speakers. thing is over here the crossovers become too pricy because of the inductors so i am not willing to use and crossovers that have the wire wound inductors.

ok, so the thing is i am planin to use some local cheap 8" drivers. and a dome tweeter. should i add any 4" drivers for the mids?

so is just need measurements for the box. i am planin to use 18mm mdf. will 12mm mdf do good?

and also i need the port dimensions and length. i just want the speakers to produce good punching bass.

please donot ask me the specs of the drivers because i dunno they are local drivers.

i am just lookin for a straight forward design.

pleassssssssssseeeeeeeeeeeeee help meeeeeeeee

[leadbelly]

Your situation is impossible to solve. You want somebody to help you design an enclosure for a specific driver that has absolutely no specs available, including a passive crossover that has no inductors. You actually have to make TWO compromises before somebody can help you.

[sr2002]

i know its impossible.

but the thing is all i need is a rough idea on what the enclosure dimensions should be.

and i have changed my plan. i'll make book shelf speakers instead.

thing is i was plannin to use 6.5inch woofer.

so i guess u people cant help?

[googler]

I guess I would say try an open baffle design and buy bobbin type inducters (which are relatively cheap).

[Jay]

Inductors are not expensive if you are willing to build it by
yourself, but you have to be skillfull. It might be a waste of time.

Ready-made crossover is not recommended. Often it is better to have
a fullrange (without crossover at all).

If you don't want to use inductor, then you need to find fullrange
driver, but don't expect great bass. Or you can use ordinary
midwoofer as fullrange driver (which is not costly).

You have a sub. Floorstander or bass hungry speaker might not
that necessary.

Designing 3-way is not easy. Unless it is perfect, it is better to
stick with 2-way. Finding a good midrange is also not easy, it is
even more inefficient to use 4' driver as midrange.

If your MDF is thin, you can include bracings.

Designing a gross crossover is still possible without driver
parameters. But for beginners, it is equivalent with using ready-
made crossover. To have an optimum box you need to measure it. You
might want to find somebody in your community that has the hardware
and software to do this.

It is easier IMO if you try to find a midwoofer (about 6-7') that is
suitable for fullrange. You can ask people or just try to feed the
driver with music signal (before you buy of course) and decide if you
are okay with the sound. A bit of harshness cannot be avoided but look
for clean and open vocal. Then you need to experiment with the box
to get an acceptable bass performance. You can use sand or anything to
reduce the box volume, and you can experiment with port length and
filler. Incorporating the tweeter is the hardest. But you can try.

That is primitive approach you might think. But, use of ready-made
x-over or begineer's cheap design usually worse. But it all depends
on how much money you are going to spend...

But there's always a better way. DIY audio is not a cheap hobby
(IMO it is the most expensive hobby!), so if you're not doing it for
hobby, DON'T DIY your speaker (amplifier is okay, because you just
use other people design hehe, and it is cheap without cosmetics box).
The best way probably is to buy used speaker.

[jomor]

Building a speaker without knowing the drivers' specs and without ... inductors ( !! ) at the crossover, is impossible to success.

It would be far better to buy a real cheap but decent chinese speaker by CAV Audio, for example something like one of these which use Audax drivers by the way (aerogel)