Playing Below Port Tune

[johnhay20hz 0]

I got a question,

everyone says that playing a subwoofer below the port tune will cause the subwoofer to be unloaded, and with too much watts it will "bottom out"

is this unloading the subwoofer basically becoming a sealed box with a 4", 5",3" etc hole in it (loss of major amount of bass)

, or the unloading making the subwoofer box be like an infinite baffle, decreasing power handling, but increasing efficiency?

if it is infinite baffle, would it have a similar 6db/octave (i think this is close) roll off instead of a usual sealed boxes 12db/octave

[bassahaulic 155]

All depends on the box, woofer, power, music, and tuning.

[johnhay20hz 0]

well how about a fi 15" x subwoofer tuned at 32 hz?

btw i dont understand how this could be driver dependent, seems like a general thing

[Duran 387]

well how about a fi 15" x subwoofer tuned at 32 hz?

btw i dont understand how this could be driver dependent, seems like a general thing

It's not, because a woofer with 10 mm one way throw will bottom out sooner than a woofer with 30 mm one way throw.

[johnhay20hz 0]

yes, but any subwoofer can bottom out with too much power

mostly im asking that if i want a infinite baffle set up can i build a high tuned ported box say 60 hz or whatever

and have an infinite baffle roll off in the lower frequencies?

[95Honda 486]

The roll-off is more around 24db/octave or greater.

Your example is not Infinite Baffle because the rear wave of the driver is 180 degrees out of phase with the front and being combined in close proximity, hence the greater than 24db/octave roll-off. Infinite Baffle means exactly that, there is an infinite space behind the driver, completely isolated from the front.

Infinite Baffle drivers also have different parameters to allow them to operated in this specific environment.

Infinite Baffle is not as efficient as a standard 4th order vented box, all else being equal...

[johnhay20hz 0]

thank you,