So what you are saying bigger box like 60"WX48"DX28"H and how about 18Sound 21" 9001 woofer Xmax is 14 mm? Any other want to chime in for help? I have access to cheap plywood can it be done just screw panels together just for measurement purposes then unscrew the panels of the mock up cab then redo it again to get the final output? Thanks!
I still don't think that will be enough. Subtract 1.5" from each longer dimension, and 4" off the shorter one, and that gives a real indication of how much volume you have to work with. In that case, 1136 liters. external flares make more sense than just continuing to grow the box. Omit the L23 parabolic segment (extension), and lengthen the exponential keeping the same F23 frequency, unitl the schematic gives you 1136 liters. I bet you won't get 77cm of extra length in there.
So why stop at 48", and not something smaller or larger? Construction efficiency. I've been thinking about this build for some time. You get both sides out of a 4x8, and you can get three strips of 28" out of another for the ends and the back. One more sheet handles all the 28" wide internals. Three full sheets for all the main panels with little waste. (No waste for a 24" wide panel for 18" drivers.) About $150 in wood if you use Purebond - which is as cheap as I'd go for a final build. If I can find 4x8 Baltic for less than $100 a sheet I'll use it, but I know I can get poplar or maple core Purebond for 50. Araucoply is $40 if you can still get it - it has dried up here. One more sheet plus all the one foot wide strips left over will do all the braces for a set of 4 or 6. Flare extensions are also efficiently constructed out of 4x8 sheets. And last but not least - stack two on top of one another, and put a third behind it and it completely fills a standard bed pickup. Unlike three lab horns, which are a hair too small and take more tie downs, and 4 are too big to fit at all.
I would use the cheapest possible wood for mock ups and prototypes. OSB for the outer box, and whatever cheap Birch they're selling at Home Depot for the internals. They usually have some 'cabinet grade' stuff on special for about $30. Not completely void free, and the internal panels are pieced together. But its relatively flat and you can at least cut it on an angle. OSB is awful for angled cuts -you want a little better fit than that.
So why stop at 48", and not something smaller or larger? Construction efficiency. I've been thinking about this build for some time. You get both sides out of a 4x8, and you can get three strips of 28" out of another for the ends and the back. One more sheet handles all the 28" wide internals. Three full sheets for all the main panels with little waste. (No waste for a 24" wide panel for 18" drivers.) About $150 in wood if you use Purebond - which is as cheap as I'd go for a final build. If I can find 4x8 Baltic for less than $100 a sheet I'll use it, but I know I can get poplar or maple core Purebond for 50. Araucoply is $40 if you can still get it - it has dried up here. One more sheet plus all the one foot wide strips left over will do all the braces for a set of 4 or 6. Flare extensions are also efficiently constructed out of 4x8 sheets. And last but not least - stack two on top of one another, and put a third behind it and it completely fills a standard bed pickup. Unlike three lab horns, which are a hair too small and take more tie downs, and 4 are too big to fit at all.
I would use the cheapest possible wood for mock ups and prototypes. OSB for the outer box, and whatever cheap Birch they're selling at Home Depot for the internals. They usually have some 'cabinet grade' stuff on special for about $30. Not completely void free, and the internal panels are pieced together. But its relatively flat and you can at least cut it on an angle. OSB is awful for angled cuts -you want a little better fit than that.
I'm with you on this one keep the dimensions as you previously stated and have a horn extension like the Levan OR Funktion with supports and bolted together for portability. I can get Russian Baltic Birch 4'X8' 13 ply exterior glue for $80 a sheet in B/BB nice smooth finish no football patches. I can also get at Home Depot cheap Chinese Birch Sandeply for $35 for building a mockup or prototype cab. I can get also cheap prices on Faital Pro 18" neo woofers I have asked Keith at Faital NJ for a new 21" woofer and they won't do it so I am stuck with PD2150 maybe in the future OR I can get good prices for 18Sound 21NLW9001, the 9601 is out of my budget but doable if need be. TnX wg_ski. I am sure we should continue on this project as you can see TH18 on here has alot of followers if I get to build one and testing proves to be worthwhile then we have a winner diyAudio 2015 best sub project!
my current subwoofer project is a dual 21. 18 sound 21nlw9001 was my driver of choice, though the lw1400 also works fine in the design (a tad more sensitive, less xmax).
its 60x60x31 and houses 2 21" drivers (think dbh218). 2v into the cab provides 100db sensitivity at 28hz, and 107db at 100hz. for true 30hz performance, at least a pair is recomended (ideally 4).
its 60x60x31 and houses 2 21" drivers (think dbh218). 2v into the cab provides 100db sensitivity at 28hz, and 107db at 100hz. for true 30hz performance, at least a pair is recomended (ideally 4).
WOW ! Thats incredible have you built it yet sine143? wg_ski is also working on a Bertha like 21" but will use his 18" woofers he has on hand, I am following with the real intent another US built and designed subs hope next high almighty sub project like TH18??? Thanks! Still waiting on plans will build a prototype and testing to follow if both of you willing to share the design.
Cubic footage wise, one of those would be two of these. I think we're all thinking along the same lines. Ultimately, 8 boxes would be constructed if this works. Gives a lot of different stacking options, with and without extensions. And just three (a single pickup load, with every cubic inch of space utilized) will murder anything else I have that fits in the same load. If these really work out well I may sell off most my other subs, because they really will be a jack of all trades.
Would it be better 2 stack then for lower output add the collapsible 4 horn extension pieces with tall supports bolted with washers for security? Do you have a sketch so we here at the forum what your idea might look like? Thanks wg_ski!
sine143 we'd like to see you creation too with 2 subs loaded with 18Sound 21" would be a great addition or option if you will for others to build? DBH218 is awesome I'm sure you guys have it all worked out for us to try here at the forum, me too will be selling off my smaller subs and just use these for sure! Thanks for the continued help and work!
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