fabricating a cabinet for my 12" dual voice coil sub

[therich]

hello to everybody this is my first post other than on the introductions board.
anyway, as the heading says, i'd like a little help with designing a cabinet for 'old faithful' my sub. i've just moved house and the current unit is far too large now so im going to make a new one.
what do i need to do in order to get a good sound? i guess there will be an 'ideal' cabinet size for the sub but i really am a novice so any help would be greatly appriciated.
was amazed when i did a search on the model number i found all the details here

http://www.schlotzhauer-versand.de/p...a070304522feee

however, its in german. it does say 30l and 72l at the bottom is that ported and non ported enclosures i wonder?

also i have no crossover / low pass filters can i make them or buy them?

thanks

[tinitus]

Yeah, the small volume is closed, and the bigger is BR, its always so

72 liter is the one to go fore, whether you want closed or BR ( port, ø100 x 150-200mm ) - or at least the smallest recomendable

Volume is netto, so 75-80 liter brutto should do (measured inside)

You want it smaller, so I suppose there is no point in suggesting 250 liter
You say your present box is too big, but doesnt mention how big it is


It is however possible that the smaller volume of 38-50 liter closed will work very good with EQ(bass boost), sensitivity will be around 85db, with a 6db bass boost around 30hz and xo around 50hz ... I suppose it will be quite nice actually
But the short Xmax means you cant play very loud with maximum EQ settings

Crossover ?? ... any plateamp with EQ will do, but you may need one with speaker level input ... depends on your preamp

Whats the rest of your setup like

[therich]

thanks for your reply.
the old cabinet is approx 800x500x600 mm, i made it about 7yrs ago to fit where the chest of draws was in me bedroom!
the rest of the set up is pretty basic tbh even 'crude' in your eyes i dare say !!
i got a mint pair of jamo d266 speakers run by a sony hi fi which is 2 x 55w rms. that does everything ie plays cd's, does radio and take input from i pod.
from there i run rca lead out of the 'record' plugs on the back which i plug into an old goodmans amp which aint brill but has a graphic eq and is 2x 50w rms, so ideal really for my sub. got some low pass filters on that (just an in line a coil winding i robbed from a pair of old wharfdale speakers) and turn everything down on the eq apart from 60hz which is right up. one channel to each side of the sub seems to work very well although i would like to now have the sub just doing the very low's, i think the cut off was a bit too high really.

loud system tho.

[chrispenycate]

Really easy to do an active lowpass before the amp, and you could even make it variable (switchable, at least)
100 watts doesn't sound like much reserve power for a sub – suppose I've been spoilt.
Do you have any electronics training? It would almost certainly be possible to draw enough current from the amp to power an external filter, but I don't know the amp at all (Goodmans were always speakers for me) so can't just put forward a circuit (and you could remove all the low frequencies that your full range speakers aren't reacting to, and take that signal back into the "tape monitor" inputs on your main amp too, if you were feeling enthusiastic, and make them do less work and probably sound better.)
A little work with a soldering iron and an active crossover makes an excellent beginner's exercise.