Hi @Hamzalakhany 

Thanks for your post!

There aren’t any figures (that I could find, anyway) that I can quote to you to give you a “correct” answer - it all depends on what you want from the system. At one extreme, you might be looking for gentle sounds for your Japanese-style Zen garden, or you might be looking to have wild pool parties with lots of people and loud music at the weekends. Even the amount of foliage in your garden could drastically change how many speakers you’ll find are needed. The elevation of the speakers could also be a factor.

All I can really recommend is buying, trying and evaluating whether more are needed or not. You may get more guidance from Sonance themselves - I also recommend asking them, though you may get a similar answer. I suppose one option, if you have the means and are looking to have the install completed in one go, is to over-buy and install what is needed, then return what you don’t need within the money-back-guarantee time frame (45 days in the US, if you buy from Sonos.com).

Hopefully, someone on the Community with Amp and Outdoor Sonance speakers installed can give you a better idea, using their own set up and experience as an example. My posting a reply here will get your topic back to the top of the “Recently Active” list - hopefully, that will help.

I have a pool in my backyard with Sonos providing the audio.  My advice would be to focus on the specific areas where people will likely be sitting/congregating rather than trying to blanket the entire area.  

I started off the space with a single amp powering 2 pair of outdoor speakers (not Sonance) on the backside of the pool and spa.  This is just fine, but I found out that there are many times where we are just hanging out in the spa, so in hindsight, it would have been nice to have a single amp for the pool and for the spa, so that I could control the volume separately and group/ungroup as needed.  I may do that some day. 

I also added a pair of speakers under the porch area.  That wasn’t necessary for audio only, but I added a TV in that space that I wanted to be connected to Sonos, but not always playing over the whole backyard.  Later I added a 3rd space, a seating area, that really didn’t get used much, but I had a port and 3rd party amp I wasn’t using.  There is a whole section of the yard that has no speakers and rarely  gets used.  If I do want music there, I bring out the Move.

So anyway, think about areas to focus on.  It might make more sense to get 2 amps and 2 pairs of speakers rather than a single amp and 3 pairs of speakers.  Depends on the space.  The 6.1 system may be good for covering the pool area, can’t say for sure without seeing the space.

A pair of 60-watt patio speakers installed under eaves 20 feet apart will give you great coverage in areas less than 300 square feet. For 300 to 500 square feet, look for 80 to 100-watt speakers; 150 watts to 175-watt speakers will cover 600 to 800 square feet with clear, sharp music sound at soft volumes.Sound travels easily in wide-open spaces so it can be tough to estimate how many watts your speakers require. The wattage levels of outdoor speakers range between 60 to 300 watts. A pair of 60-watt speakers installed 20 feet apart provides good coverage for areas less than 300 square feet.An office with a ceiling height of 2.5m (8ft) makes one speaker cover an area with a 7.5m diameter (3 x 2.5m), which makes the cover area 44m2 (3.14 x (7.5/2)2). If the total floor area of the room is 700 m2, then you need sixteen (700/44) speakers.Generally, separate your speakers as much as possible but no more than 20 feet from one another. Try to point each speaker toward a central point where the optimal sound will converge. If you have a space of between 200 and 400 square feet, two speakers should suffice.As a rough rule of thumb, if it is an indoor gig, you should aim to have as a minimum around five watts per person. If you are playing outside or want “rave volume”, then you will probably want to double that and have 10 watts per person.Take the speaker's voltage and multiply it by the amperage to get a rough estimate of the maximum wattage. For example, if your speaker has 120V and 5A, multiply these numbers together to get 600 watts.Try to get about 4 feet of separation for bookshelf speakers or 8 feet for floorstanding speakers. If your speakers are too close, sounds will blend together and become muddy.