Myth #1 - A 1000W amp will be so ridiculously loud that it's stupid.
Truth #1 - When driving a perfect loudspeaker a 1000W amp is only twice as loud as a 100W amp. When driving a real loudspeaker that suffers from thermal and mechanical power compression a 1000W amp will be less than twice as loud as a 100W amp, probably only about twice as loud as a 50W amp at best.
Myth #2 - The higher the cab power rating, the more powerful an amp you need to prevent 'underpowering'.
Truth #2 - Generally the larger the cab, the higher the power rating, because it's determined by the power handling of each voice coil added together, the bigger the voice coil the greater the power handling (bigger or more expensive speaker tends to equal bigger voice coil), and the greater the number of voice coils the greater the total power handling. The larger the cab and/or the greater the total cone area, the higher the sensitivity and thus the LESS the amount of power you need to reach gig SPL.
Myth #3 - If your amp isn't powerful enough you risk blowing your speakers through underpowering.
Truth #3 - You will never blow woofers or mid-bass drivers, i.e. the 8"/10"/12"/15"/18" speakers found in a bass cab, because your amp isn't powerful enough.
Myth #4.1 - Clipping blows speakers because it creates DC or square waves.
Truth #4.1 - Clipping does not cause DC. Clipping does not cause square waves.
Myth #4.2 - The square waves caused by clipping mean that the woofer has to stand still all the way in, then instanteneously leap all the way out, then stand still, then leap all the way back in again and so on, which causes the woofer to break due to the harsh movements and the lack of cooling when the woofer is stationary.
Truth #4.2 - If you were to apply a square wave to a perfect loudspeaker it would move steadily out and then steadily back in, because the cone position is the integral of power over time, which gives you a symmetrical triangular wave. However all woofers and mid-bass drivers have sufficient inductance that the square voltage wave from the amp does not result in a square current (and thus power) wave due to the lowpass nature of a series inductance.
Myth #4.3 - Clipping hugely increases the power output from the amp due to the square waves
Truth #4.3 - Clipping only increases the power output at higher frequencies. Due to the lowpass nature of the voice coil inductance very little of this extra power is delivered to woofers. However this extra high frequency energy can blow tweeters or midrange drivers if the clipping is heavy and prolonged. Most rigs will clip at some point during a gig, some on the majority of louder notes - however this gives times in between those moments of extra HF energy for tweeters to cool down.
Myth #4.4 - Clipping is really dangerous to speakers because of the extra harmonics and thus HF power it generates.
Truth #4.4 - The extra harmonics and HF power generated by power amp clipping are no different to those generated by preamp clipping or distortion or fuzz pedals. This kind of distortion rarely sounds good through tweeters, and thus the unpleasant sound tends to protect them from being blown as most sensible people turn the tweeter down before damage occurs.
Myth #4.5 - Clipping is always bad so you should turn down if clip lights flash.
Truth #4.5 - Every bass player will cause their amp to clip at some point on the gig, the dynamic range of bass guitar is too large for this to be avoided. Frequent clipping is not a problem. Only near-constant clipping is an issue due to the lack of cooling time in between 'clips' for the tweeter/midrange driver. If the clip light is almost permanently on, or you can hear the clipping almost constantly, then turn down or reduce your lows.
