Wow! Thanks for all the helpful advice!

I've never played outside, so I have no idea of how the sound dynamics change as compared to indoors. It would seem from your replies that the issue is mainly that the bass frequencies are lost.

There will most likely be bass guitar in the songs, either myself or the pianist will play the bass. However, I would like to keep the lineup as small as possible, since last time I did something like this, it was such a huge hassle to get everyone together to practice, and even when we would set dates, someone would back out at the last minute. The way that I'm doing it this time, there's only three musicians and two alternating vocalists. That way, the three of us can get together and work on the music, and whenever the vocalists are available, they can practice with us.

I guess I should have gone into further detail about the neighbourhood that I live in. I live on the corner of a small court and my backyard backs on to a small park. Therefore, I have no concerns about noise to the rear, and I'll actually be pointing all the speakers in that direction. The only concern with my neighbours are the ones to my right and left. Like Blaksmith recommended, I've decided to play for just 1 hour and at around 5 pm, so there's not a big concern about disturbance.

Also, I've chosen songs that aren't too all-out rock [:(], given the location.

Chacron - I live in Toronto, so I doubt you'd catch a plane from BC for just 1 hr's worth of "entertainment". And unfortunately, I'm not playing any Pink Floyd...too inaccessible for the crowd I'll be playing for (curse those dance music freaks!)