- It’s power that kills drivers
- High power amps are safe if you can fully control their output - this means know your volume knob’s "levels", and adopt patterns that prevent transient spikes - e.g. power on/off in the right sequence, mute when cueing a stylus, control LF feedback and woofer "flapping" if you have a turntable (through proper isolation) etc.
- Low power amps are safe if you keep them away from clipping conditions. At some point, power output may be low enough that even clipping doesn’t harm your tweeters - but I wouldn’t go looking to experiment on that.
- Tube amps are bandwidth limited at higher power levels, which causes their clipping wave to be *slightly* rounded compared to SS. But I can confirm, a typical tube amp’s hard-clipping still sounds like sh*t and can damage your tweeters - don’t rely on tube amps being much "safer" here.
- High efficiency speakers aren’t always correlated to higher or lower power handling. You can usually play louder safely with high efficiency. That’s why aficionados of loud sessions like me love them :)
- Tweeters typically have much lower power handling levels than woofers in the same speaker - up to an order of magnitude less. This is normally OK because like "pink noise", musical content carries much less energy above 4KHz (etc) than below - "equal energy per octave".
- When you force an amp into clipping, not only does it carry up to 2x the amount of continuous power versus unclipped (basic math - area under a sine curve versus a line), it also "rewrites" the signal to have a higher proportion of high frequency content. This is especially true for "peak" power. This is why it puts tweeters at risk - they’re not designed to take as much power as the woofers in the same speaker, so they’re sitting ducks under clipping conditions.
- Woofers are more at risk from poorly isolated turntable setups. Poor isolation and uncontrolled resonances can cause low frequency feedback. In the subsonic range, this is seen as woofer "flapping" - =-- besides power from the huge amplitude, it can cause woofers to hit their excursion limits and damage the voice coil. In the audible range 20 - 120Hz, LF feedback may be confused for ground hum at lower levels, and can even cause runaway feedback at higher levels. LF feedback can even get so bad it pushes your amp into clipping which then "suddenly" generates a HF spike (a very, very loud POP) that can kill your tweeters!
