need help building woofer enclosures

[thatotherguy]

i had some old loudspeakers, and i took the drivers out to make a 2.2 kind of arrangement. the 2-way satellites turned out mostly fine, but the woofer enclosures are way to small, and sound terrible.

the new enclosures have to be about 1.06 (1.05966) cu. ft.(that is what the original enclosures were). they have to fit under my bed. it is about 7.75" tall. they should be no more than 2' wide and about 3' deep( at most about 3.5'). now i have a few questions. what kind of wood should i use? pressed wood or normal wood? will the fact that they are so deep make a difference since they will be ported?

here is the final problem. the bed is 7.75" tall and they are 8" woofers. i will most likely make the front slanted so they will fit. will any other configuration besides standard front facing work? the crossover is at 800hz. will facing up or down firing work(the floor is hard wood)?

[thatotherguy]

bump?
what kind of wood, and will the deep enclosures mess with phasing?

[Rademakers]

MDF or plywood (i.e. baltic birch). 800 Hz sounds pretty high, how far are the satelites from the woofers?

Regards Johan

[thatotherguy]

the satellites are 4-5 ft. from where the woofers will be. i was planning on using the original crossover because i think there might be some sort of filter in it. I had intended on changing it because its old, and there are what look like iron core coils in it, but i recently discovered the strange design, and also at least one of the three caps is mylar(one is electrolytic, the other is unmarked)(do mylar caps age? i didn't think they did, but what do I know? lol).

so is MDF like normal pressed wood/particle board? Where can i get it? and is[the plywood you suggested] it any type of special plywood?

thanks for the reply.

[Rademakers]

http://en.wikipedia.org/wiki/Medium-density_fibreboard

http://en.wikipedia.org/wiki/Birch is used as a standard in professional audio because of the stiffness of the board and resistance against fairly rough treatment (handling),

I think it's common practice to put transducers no more than a wavelength apart based upon the crossover frequency, or 1,4 ft in this case.

Regards Johan

[thatotherguy]

once again thx for all the info.

this is my most recent idea, plz tell me if this is a good idea, or just dumb

after pricing crossovers, i realized that a mediocre three way second order crossover would be over $100. considering i rescued these speakers from the trash, i figured it probably isn't worth it (don't get me wrong, they sound excellent). what about an electronic xover like this? http://www.partsexpress.com/pe/showd...number=265-128
before i get too carried away with designing around this, does this need to be wired before the amp? basically, what does low level input mean?

Considering I can use this after the amp(or one like it), i was thinking about replacing the mids, and turning the woofers into true subs with that xover. Am I crazy?
*edit sry is this to big of a topic change? should i repost?*

[Iain McNeill]

it's your thread. I think you can do whatever you want with it.

This is a line level crossover suitable for bi- or tri-amping where you have an amplifier per driver - it goes before the amplifiers. I like this approach because each amplifier has complete control of it's driver, none of this driving through a leaky spring business.

and it looks like your pricing of passive crossovers concurs with mine: it's cheaper to build/buy power amps.

Things can get very complicated in a hurry with active crossovers and without good acoustic test equipment it'll be hard to dial in a good response.

I'd say start with a simple passive first order C across woofer L across tweeter (woofer & tweeter in series) and listen. That's a very good reference from which to start modding.

[thatotherguy]

I'd say start with a simple passive first order C across woofer L across tweeter (woofer & tweeter in series) and listen. That's a very good reference from which to start modding.

i don't exactly get what your saying, i've never done crossovers in series, so i don't know how. is it the same as parallel or what?

i don't know if this will help any, but right now they have first order parallel xovers. tweeter is 3k mid is bandpass at 3k and about 550hz (with the exception of the woofer which is in the original enclosure with a steep 800hz high pass).

[thatotherguy]

update/bump

i put second order 4000hz crossovers on the tweeters, and they sound much better, although quieter. by the sound of it, i think i'm going to need to redo all xovers with second order. are zobels and notch filters good ideas to use? do you think 200hz is too low for the woofer? original was 800, but the mid seems to be able to handle quite a bit of bass. my only fear is that it might blow at high wattage. any ideas are appreciated.

[thatotherguy]

*sigh*

ok i was thinking of replacing the mid with a small woofer like this... http://www.partsexpress.com/pe/showd...number=290-373
do you think that this would be ok for a mid in a sealed enclosure? then i would cross it over to the woofers at about 100hz. if the woofers were crossed over there, as true subs, i shouldn't need a zobel should I? will i need one for the mid? what about a notch filter for the tweeter? the tweeter will have a 2nd order xover at most likely 4k hz. will this need a notch filter? *ah, and one more thing, i was intending on a steep tweeter and sub xover, but what about the mid? should i put a steep one on that as well?*

sry for all the questions, but obviously i don't really know what i'm doing lol.

(bumpbumpbumpbump!)