robgrow said:
I've found the Wizzy to be very comfortable when driven by my green light Walter Woods which can develop 450 watts into 4 ohms. There's never even a hint of any strain or distortion. As Chris says, just use your ears. In general it is a very good thing to have lots of headroom.
Gosh, maybe I should just write a long post that would qualify as a sticky. The notion that too little power kills more speakers than does too much comes from the hi-fi world and is quite true. When a power amp reaches its limit, it clips. The resultant squaring-off of the desired waveform transfers vast quantities of energy to high frequencies. This kills tweeters. They're the first to go under such circumstances. So, if you are using multi-driver systems, yes, you do need to worry about too little power.
The situation with driving a cabinet with an amplifier well above its power-rating is a bit different. For woofers especially, over-driving typically produces audible warning-signs. You can hear the cone being over-driven and the resultant "break-up." So yes, use your ears.
Now, with regard to the notion that you can never have enough headroom, that is just plain false. (
robgrow, I'm not picking on you and I know you didn't say that but it was implied in other posts.) As I've noted in these threads many, many times before, what counts is sound-pressure level.
See
here and, especially,
here.
No, there is no real advantage in buying as much power as you possibly can. Those who would have you believe that there is any practical advantage in this are mis-informed. One must also keep in mind that every doubling in power is a change of 3 dB. See
here.
Finally, it seems useful to define "headroom." That spec refers to the amount of power an amplifier can deliver over and above its continuous rating for short, "transient" periods. Both the continuous power rating and the headroom rating should be accompanied by a specified level of distortion. The formal headroom spec also includes the "burst" time over which the transient capability is to be measured but I won't go into that.
The botttom line to all of this (especially if you actually read those links) is that one should consider the sensitivity of the cabinet(s) in terms of SPL, and the power-rating of the cabinets and buy an appropriate amplifier. In general, too much power will not hurt at all (if you use your ears) but you may end up wasting $$$ if you adopt the "more is always better" attitude.