From the Sonos Amp FAQ:
Is the 125 W/channel a peak rating or rms/continuous?
Amp provides 125W continuous average power sine wave, into an 8 Ohm load, both channels driven.
Based on this information, I would go with Option 1.
They will work fine. Of the three options, going with 2) is probably best. The slightly broader Frequency Response of 3) isn’t going to matter outdoors, and 2) are more sensitive, so they’ll play louder using less wattage.
And by the way, of those three specs (Freq. Resp, Sensitivity, and Power Handling), Power Handling wattage is the least useful. Which is funny, because it’s the one everybody knows, but it really means nothing unless you are using way too much amp.
The sensitivity is the most important spec unless you have a huge (1000 W) amplifier.
Outdoors where you get little or no room reinforcement it is even more important.
Dig up an article on speaker sensitivity, amp power and actual sound levels for a better understanding of the issues. I would for you but the spouse is waiting on me to finish the last two posts...
I vote for option #2 because there are more speakers. That outside “room” is rather large and a higher speaker count will give you more even coverage without needing to drive a given speaker at a higher level. For example, if you place a single pair of speakers at one end of the venue, listeners close to the speakers will be unhappy because the speakers will be “loud” while listeners at the other end of the area will be unhappy because the speakers will not be “loud” enough. Two pairs will give more uniform coverage for everyone. Everyone will be aware of the music at more reasonable levels. And, option #2 will be less likely to annoy the neighbors.
Option #3 will require more amplifier power for the same acoustic output as option #1.
I vote for option #2 because there are more speakers. That outside “room” is rather large and a higher speaker count will give you more even coverage without needing to drive a given speaker at a higher level. For example, if you place a single pair of speakers at one end of the venue, listeners close to the speakers will be unhappy because the speakers will be “loud” while listeners at the other end of the area will be unhappy because the speakers will not be “loud” enough. Two pairs will give more uniform coverage for everyone. Everyone will be aware of the music at more reasonable levels. And, option #2 will be less likely to annoy the neighbors.
Option #3 will require more amplifier power for the same acoustic output as option #1.
Agree with all this, but wanted to add a few more comments. First. you didn’t mention how big the overall space is. For most, 4 will be good, but if you have a larger pool area, perhaps with multiple seating areas, or areas where you expect people to congregate, then perhaps more than 4 is the way to go. And speaking of seating areas, if you’re putting in a spa/hot tub, then it makes sense to use a pair of speakers centered around that area, if you suspect that you’ll actually use it a lot.
The third point, that’s still really related to the other points, is that the problem with rock speakers, IMO, is that they aren’t that great at directing the audio where you want it. People use them because they get the speakers away from the house pointed where they send audio into the neighbors yard...which is good idea, yes. However, I didn’t use them for my yard because I didn’t want the audio coming from the ground, nor really felt the need to hide my speakers. So instead, I got normal outdoor speakers and mounted them on fence posts placed about 4 feet off the ground in the locations I wanted them, pointed in towards the house so as not to disturb neighbors. Again, not sure how ‘scientific’ that plan is, but I was happy with the results.
