push-pull design

[Brett]

Originally posted by fwater
Two woofers in series will require around the same volume as one woofer for the same bass extension

Unibox shows no difference in Vbox for two drivers in series or parallel to get the same Qt and F3.

[nukaidee]

well.. essentially I'm trying for a multidriver.. smaller than standard bookshelf speakers with decent everything. sounds impossible.. i know..
my current plan..
exterior - single box style, interior is going to be 2 different spaces, so hidden baffle.
bass - 1 or 2 (isobaric) 3 inch subs from tangband
top section - full range drivers from tang band (3")

its just a thought for now. isn't heavier better? =P but I want to keep it small, and the sub will be downward firing, speakers will be on 1 inch standoffs.

oh. btw. anyone know where else to get tb speakers in canada? solen doesn't have any bamboo series.

[tinitus]

Originally posted by Brett
Unibox shows no difference in Vbox for two drivers in series or parallel to get the same Qt and F3.

i did wonder about that one too

[fwater]

Originally posted by Brett
Unibox shows no difference in Vbox for two drivers in series or parallel to get the same Qt and F3.

Jeff Bagby's Box Modeller 3.20 shows differently. In some (maybe many) cases, the f3 will appear similar in numbers, but the Qts is different for either wiring, even if you're using the same volume. The curve also appears different, the rolloff often having a hump or sometimes a more "rounded" bottom. The volume requirement for similar output isn't exactly 50%, more like 60-70. I can't recall exactly why this is, maybe someone a little more well-read will jump in.

[fwater]

Originally posted by nukaidee
well.. essentially I'm trying for a multidriver.. smaller than standard bookshelf speakers with decent everything. sounds impossible.. i know..
my current plan..
exterior - single box style, interior is going to be 2 different spaces, so hidden baffle.
bass - 1 or 2 (isobaric) 3 inch subs from tangband
top section - full range drivers from tang band (3")

One single (mono) box containing all the drivers or two (stereo) boxes each housing a woofer and a fullranger?

I am continually impressed by the amount of bass that can be extracted from any number of 4" drivers, but that 3" woofer might not get you any satisfying output in any other situation than desktop comuter speakers. A quality 4" do the job that you're trying to accomplish. At any rate, I can't think of any situation where the tiny volume requirements for a 3" driver would need to be reduced even further, unless it's going into a matchbox car

[nukaidee]

ok ok i can do a footprint of 4" =P
lets see if i can explain it better..
this is going to be a stereo setup, 2 boxes in total. each "box" will house 2 drivers, 1 full range and 1 subwoofer. each will be separated by an invisible sealed baffle? i think that is what you call it.. i don't mind porting the sub, but i think i calculated something stupid like 0.5 inches in diameter and 2 inches length.. where am i going to find pipe like that.... if you say the 4" are good, can you recommend one? i'm trying to source them in canada, and hopefully around 25-30 each. the enclosures will be mdf.

thanks for your help!

[fwater]

Originally posted by nukaidee
ok ok i can do a footprint of 4" =P
lets see if i can explain it better..
this is going to be a stereo setup, 2 boxes in total. each "box" will house 2 drivers, 1 full range and 1 subwoofer. each will be separated by an invisible sealed baffle? i think that is what you call it.. i don't mind porting the sub, but i think i calculated something stupid like 0.5 inches in diameter and 2 inches length.. where am i going to find pipe like that.... if you say the 4" are good, can you recommend one? i'm trying to source them in canada, and hopefully around 25-30 each. the enclosures will be mdf.

thanks for your help!

O.K., now I get it, we're simply using just a little bit of different language. A baffle is the name given to whatever seperates the front wave from the backwave (usually the front of the cabinet), what you're referring to can simply be called a separator or divider.

A 4"x4" footprint isn't very big. If the enclosure could be 36" or more tall, then there would be something to work with. At 12" tall, you're going to net less than 1.5 liters. I can't think of any 4" driver that could live in that volume with any output below 100Hz. I also can't imagine that a 3" driver would do any better, even if the Fs is 65Hz.

By no means do I want to discourage anyone, but if it's bass you're after in this small of a package, I cannot see a way to do it, even with an isobaric setup. If you can do a seperate sub in a more remote location, then I have a list of the usual 4" suspects, but a 3" fullranger will probrably do a fine job at less cost.

[burnett]

reminds me of this commercial design:
http://www.barefootsound.com/products_mm27.html

looks like a kind of push pull thing:
http://www.barefootsound.com/technology.html

J.

[nukaidee]

yeah! something like that.. actually you're right too.. the footprint is really small. what if i do something like a 6 x 8 x 14 wxdxh... i dunno. i need to run it through the calculators again.. which calculator do u use?

[burnett]

that's not my design, sorry.

all I know about it is, that the tweeter is a scan speak (probably a 9500 or 9700), the mids are from vifa (p13 I think), and the subs look like some peerless (x)xls 10 aluminium.