WinISD pro to simulate 6th order bandpass subwoofer

[Cro maniac]

Cristophorus,

you have low Q driver, so it is optimised for use in small boxes (BR or use with PR). I recommended such a small, low-tuned BR box because it it gives rolloff similar to closed box which best integrates with car cabin gain.

Blue graph gives rolloff of only 3dB/oct, so it will have have strong rising response to lower frequencies when placed in car.No good.
I you'd like to turn some heads when driving by, but still want to attain relatively flat curve, then aim for something in between red and yellow curve.
I don't think that yellow curve would give you boomy bass because you usually shouldn't cross-over your sub higher than 80Hz, because mains can take care of the rest of the spectrum, you will avoid main car cabin resonance and subwoofer localisation problems. 120Hz really isn't something that you should need sub for. I usually like to cross-over my subs between 40-60Hz and leave the rest to the mains (if they are up to the job).

[christophorus]

Hi Noodle_snacks,
Why I add 1 ohm resistor, because it raised overall SPL by 1dB.
If it's not good, I pull out that resistor.

Hi Cro maniac,
to get in between red and yellow curve, I change box dimension to 36 liters.
How about adding mass? When I add 20grams mass, in Transfer function magnitude graph overall curve raised by 2dB! but SPL graph barely changed.
Is it a good idea adding mass to cone?

Thank's
Chris.

[Cro maniac]

Series resistor will only ruin the ability of the amp to properly control your sub.
Also, one fifth of the power of your amp that you should be using for sound will be lost in resistor heating. That's 75W of heat for 300W on sub.

All manufacturers of drivers try to get speaker cones lighter, and you try to get them heavier
With heavier cones you lose sensitivity. In your case, it only attenuates higher bass frequencies, so at first sight it may seem that low bass sensitivity is increased (transfer function), but when you look to SPL graph, you see that in <60Hz region nothing has changed. So, forget adding mass to driver.

[christophorus]

Thank's Cro maniac,
so it's better for WinISD creator to delete adding mass and series resistor option, if it makes no good at all.
I think I reach the optimum design for my "not so good" spec. driver and start making wood dust.
I will post here when it done.

see you.
Chris.

[noodle_snacks]

the series resistance is useful when you are simulating the response of midwoofers in an enclosure that would have one or more inductors in the low pass crossover (inductors have a DC series restiance)