15" PA speaker output wattage limit for 65hz-?

Question

I just bought a Radioshack 15-inch speaker rated at 150watt RMS range 35hz - 18khz. I am using my soundcard to limit output directed to it to 0hz-65hz IE designating it as a sub-woofer. I know it can handle 150watts RMS distributed between 35hz-18khz, but what fraction of 150watts can it concentrate between 0hz-65hz without damaging the speaker?

Answer 1

You can always adjust your output to limit the distortion. If the speaker is not distorting then you will most likely be ok. I doubt you will be able to pump 150 watts of bass into the speaker though. Keep in mind a full range speaker is not designed to run in a bass only mode. Its construction can not handle it like a real sub woofer can. The surrounds (speaker's support/suspension) are not as strong, The voice coil is not as big. The cone is not as durable.

150 watts in bass frequencies puts a huge physical stress on the speaker. Sub woofers are designed to handle this physical stress. A full fange PA speaker is primarily meant for midrange frequencies with the occasional ventures into the higher and lower ranges.

You are much better off to buy a sub woofer if you can swing it.

Answer 2

It'll start distorting the sound below 35 Hz.

There are a lot of other things that come into play apart from just the watts. Damage will come later. First it'll be poor sound quality.