Indeed, wattage is just part of the equation.. Average watts per channel RMS (root mean square) is an average which means there will be peaks and valleys of power output way beyond and way below the RMS value. Amplifier manufacturers that do not state power in watts RMS per channel is quite meaningless or hard to understand what they mean. And the quality of the first watt is super important. For instance, Klipsch Heritage speaker line with efficiency up in the 98 and above can easily be powered by a 2.3 watt/ch SET amplifier from Decware (see Steve Guttenburg's YouTube channel on this very topic) if you listen at a relatively reasonable level (vs a night club !). There is an obsession on the more watts, the better. That is not necessarily true. PLUS, some speakers have impedances that are all over the map and can approach zero ohms (e.g. almost a short circuit) and that requires a very well designed amplifiers (e.g. David Berning's) more than just powerful amplifiers.
how can low watt tube amps drive speakers with higher power requirements
I am new to hifi and I am super confused about something. Most audio blogs out there ask newbies to stick to amps that output power within the recommended range of the speaker manufacturers. However, on forums, blogs and even some magazine articles, I find pros reviewing tube amps with much lower output power (even in some cases 10-30W below the speaker specs) and find no problems. How can these low power tube amp drive these speakers? For example, the LS 50 metas spec sheet says "Recommended amp power: 40W - 100W) but I have seen posts here and on other forums where people will hook these up to tube amps producing as low as 12W of power at 8 ohms. Am I missing something?