That sounds like a hell of a lot of bass! I think I saw a post that you liked some pretty heavy bass music, your name is kind of leaning towards that too haha.
Well this is where the decisions come in. First off I now see that flaring both ends is the way to go looking at throat and mouth velocity sims. BUT, when I compare this box to the Karflex design posted by tb46 here:
http://www.diyaudio.com/forums/subwoofers/259509-new-sub-design-constricted-transflex-simple-build-series-tuned-6th-order-119.html#post4236575
The larger 80L + double flare port has only 1.6 dB more output over the exact same tuning...
Thats a 42 Liter larger cab for an extra 1.6 dB... should I be getting more output for that volume increase?
I am calculating an extra 6.4 liters added from flaring the ends which then gives me an 18 x 21 x 24" cab using 3/4" ply, a nice and neat 18 x 22 x 24" if I add and inch to allow for a full front metal grill!
The Karflex on the other hand is only 16.375 x 18 x 22" using half inch ply.
One last point. Using WinISD to design a small BR box for my LAB12, I specified a 35 Hz tuning and built exactly to spec; SolidWorks confirmed internal volume accounting for bracing, driver and handle. When built, I confirmed excursion minima to be at 31 Hz. Is there any way to account for this drop in tuning? My solution would have been to build the box leaving one side removable, then attaching the last section of port and last side with screws and foam rubber to test for Fb and modifying if necessary.
Well this is where the decisions come in. First off I now see that flaring both ends is the way to go looking at throat and mouth velocity sims. BUT, when I compare this box to the Karflex design posted by tb46 here:
http://www.diyaudio.com/forums/subwoofers/259509-new-sub-design-constricted-transflex-simple-build-series-tuned-6th-order-119.html#post4236575
The larger 80L + double flare port has only 1.6 dB more output over the exact same tuning...
Thats a 42 Liter larger cab for an extra 1.6 dB... should I be getting more output for that volume increase?
I am calculating an extra 6.4 liters added from flaring the ends which then gives me an 18 x 21 x 24" cab using 3/4" ply, a nice and neat 18 x 22 x 24" if I add and inch to allow for a full front metal grill!
The Karflex on the other hand is only 16.375 x 18 x 22" using half inch ply.
One last point. Using WinISD to design a small BR box for my LAB12, I specified a 35 Hz tuning and built exactly to spec; SolidWorks confirmed internal volume accounting for bracing, driver and handle. When built, I confirmed excursion minima to be at 31 Hz. Is there any way to account for this drop in tuning? My solution would have been to build the box leaving one side removable, then attaching the last section of port and last side with screws and foam rubber to test for Fb and modifying if necessary.
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Doubling the cab volume should give a potential 3dB sensitivity increase. If you just put the same driver in a 2 x larger reflex box, you would get about +6dB at tuning and very little gain higher up. +1.6dB, whilst it is only just noticeable, it equates to the same as 50% extra amp power.chips and palsa said:
I've tried sims of the first woofer in that list or the hp1060, and it seems to need a 90L box for 40Hz which means larger amplifiers and less room for ports, which means port velocity can go up.
For sheer output for the size in a super portable rig it looks a good way to go. If I was to redesign my 3012lf cabinets (18" x 18" x 22" external using 1/2" crap ply for 1 cab, and the other is 3/8" BB) for a 15 I would use longer 50 sq in ports instead of 32 sq in, but the velocities would still be high. Flared ports might work, but in all honesty this woofer seems better for horns and 6th order bandpass.
The dayton = less power and more room for ports, but larger box. It's a toss up.
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