Well, finally got time to model the woofer module. Port velocities are astronomical, so I’m not thrilled.
Outside dimensions 25.5” tall, 20” wide, 24” deep
Estimate 5cu net after driver, bracing and ports.
Model is designed using two or three 4” precision ports. 2 will fit easily as designed. 3 I will have to use the inside flares and glue them in place in sculpted cutouts. Obviously, I’d prefer to use two.
Models were performed in HornResp, which predicts much higher velocities than WinISD, and higher tunes.
Input power: 1250w
Crossover: 40hz butterworth hpf, 2nd and 4th order.
2 ports, 10” net length, 650hz first port resonance.
2nd order: 46m/s. 4th order: 29m/s
3 ports, 17” net length, 400hz FPR
2nd order: 28 m/s. 4th order: 16m/s
2 ports, 6.7” net length, 1000hz FPR
2nd order: 62 m/s. 4th order: 51m/s
3 ports, 11” net length, 600hz FPR
2nd order: 42 m/s. 4th order: 34 m/s
2 ports, 4” net length, 1500hz FPR
2nd order: 81 m/s. 4th order: 81 m/s
3 ports, 7.5” net length, 900hz FPR
2nd order: 53 m/s. 4th order: 52 m/s
Here’s the pretty picture:
Not very pretty, honestly.
The most usable response appears to be the 35hz tune, 4th order HPF.
On two ports, the velocity is stupid.
On three ports, the first port resonance is getting very low.
Maybe I can bump the tune down a hz or two on two ports and see where I’m at.
I have no idea how much of the 1250w I will actually be sending at these, so port velocity may be much lower.