Speaker wattage question

My speakers are rated 15 watt - 200 watt. Before I was using 60 watt amp, now using 120 watt, and it is definitely better, though the quality of the current amp is higher as well. I sometimes listen to jazz/rock fusion at relatively high volume for couple of hours straight - nothing happens. The amp feels very relaxed and so do the speakers. In the case of the speakers that I have I wouldn't want to stay closer to the 15 watts than to 200 watts.
That math is too complicated for me. But the question was not about the precise figures but about real life situation and the position of the volume control. Anyway, I guess that this is the kind of situation when you cannot just rely on your hearing not to damage the speakers.
It appears that as it is often the case there is no general answer, it all depends on the particular application. One thing is certain though - when choosing speakers first choose quality drivers not nice cabinets and fancy crossover work.

That math is too complicated for me. But the question was not about the precise figures but about real life situation and the position of the volume control.

sorry. I thought i had simplified it as much as i could. 
Well, one thing you could do it measure the SPL at your listening position with a RadioShack SPL (or any other) meter & see at what volume knob setting you are getting 91dB SPL average (which corresponds to 10W), 101dB SPL average (which corresponds to 100W) & what the peaks are at each of those volume knob settings. That will tell you how much you can crank it up & be safe with your speakers.

One thing is certain though - when choosing speakers first choose quality drivers not nice cabinets and fancy crossover work.

mostly true. Remember that cross-over networks can make or destroy your speaker. I.E. you could have quality drivers in your speaker but a really crappy, current hogging x-over driving those quality drivers & you will end up with an overall shitty speaker.
In the end, the quality drivers, the x-over & the cabinets are all tied together. It's difficult to separate them as individual pieces. Another example - you could have quality drivers, a 1st-rate x-over network but your cabinets side-walls could be weak & resonate too much w/ the music. Once again, the result will be shitty (with too much bass boom/overhang) & you would have wasted your $$ on quality drivers + x-over in an ill-designed cabinet.
All 3 items you wrote need to work in compliment w/ each other for the speaker to be sounding its best.
Yeah for sure don't buy a fancy speaker cabinet when you know that the drivers aren't top quality. 

Of course, all three elements must come together to make good speaker, but drivers come first, that's the start.

Hi all, I know 165 watts sounds like a lot but it is not a huge amount.

The way to think about this in my opinion is in dB.

100 watts into 8 ohms is a 20 dB amplifier  referenced to 1 watt of power and you add that 20 dB to the 1 watt efficiency of your speakers.  
When talking power 3 db is twice the power so 165 watts is close to 23 dB added to the 1 watt efficiency of your speakers.
a 1000 watt amp is 30dB of power.
So if you decide 1 watt is the reference power level
Then 10* log of (RMS wattage of your amp) is how many dB it adds to the 1 watt efficiency or sensitivity of your speakers.
If you do that with your 165 watt amp you come up with 22.16 dB added to say 90 dB for a total sound pressure level of 112.16 dB at 1 meter.

General rule of thumb if your speakers sound clear you aren't putting in too much power if they sound distorted you should turn it down and see what is going on.


This is how JBL determines maximum power level and it is run for 8 hours to sense failure not distortion.
https://www.jblpro.com/pub/technote/spkpwfaq.pdf

other companies may do it differently.

You can always install a fuse on the speaker cables to insure that you won't damage them...