If bandwidth and gain are inverly proportional then could i?.........................

[Boscoe]

Make an amplifier with the bandwidth from 0-200Hz for a subwoofer therefore considerably upping the gain and so wouldn't need and amplifier that uses as much power so I could make it cheaper? Would this be possible?

Thanks
Boscoe

[theAnonymous1]

Maybe it's just me, but your statement makes little sense.

[Frank Berry]

Gain and output power are not the same thing.
As a rule, IC's have a limited high frequency response as the gain is increased.
You can increase the gain all you like but you won't get any more output power into the loudspeaker. For that, you need a heftier output stage and higher voltage from the power supply.

[Boscoe]

okay fair enough! My mistake thanks anyway

[jcx]

more loop gain can be used over the "working frequency" if the working frequency is much lower that the feedback loop "unity loop gain intercept" frequency

this could reduce distortion at the low working frequencies

but you need to know a fair bit before messing with modifying Class D feedback loop gain

if your amp uses feedback correction and is designed for 20KHz "working band" you likely already have lots more distortion reducing loop gain at 200 Hz than at 20 KHz since most feedback amps use dominant pole compensation that gives a "single pole" integrating error amplification

but increased feedback, loop gain cannot give more output power - feedback only tries to "steer" the output stage more accurately