I hope someone will be able to help with this issue. I have installed 2 Boston Acoustics' Voyager RK8T2 Outdoor (Rock) speakers in my yard. I'm using a JBL 50W / channel amplifier. I connected a bluetooth adapter to the amp and I can play wirelessly from my phone or ipad - nice setup. The sound is awesome. I have the speakers in the corner of the backyard on either side of a gazebo pointing towards the yard. The problem I have is that in my yard the sound is great. BUT, . . . in my neighbors' yards (behind the speakers), all they hear is the booming bass (e.g. like hearing a high powered car stereo as the car passes by with the windows up - all you hear is the thud, thud, thud of the bass). I would like to keep peace in the neighborhood by somehow "trapping the bass" before it rattles my neighbor's house. The rock speaker has a 8" woofer and two 1" tweeters, with a published frequency response of 50Hz-20kHz (+/- 3 dB). Bass sounds good in my yard, but too loud in others' yards. The other houses are approximately 30-50' away from the speakers.
I have seen plans on the web for building a bass trap - 2' x 4' x 4" thick with Rockwool or Owens Corning 703 inside with cloth on the front and back. But, I don't think this would work well outside in the elements (rain, heat, wind, etc.). I have heard of some plans having mylar on the front and plywood on the back of the trap, which might help with adding some longevity to the trap's effective life - but does that hurt the efficacy of the trap? Can I put mylar on the front and back and try to seal it in? Any suggestions for builds that would make this work for outside?
Are there other designs that might work? e.g.:
1. build a short landscape (precast concrete bricks/blocks) wall behind the speaker (speaker is 18.5"W x 15"H x 13.5"D) to try to absorb some of the bass? How high/wide would I need?
2. put a piece of Lexan (1/4" plexiglass / polycarbonate) sheet behind the speaker? I could potentially bend the lexan into a 30 degree angle or connect 2 pieces to create a bend, to further block some of the sound or potentially tilt it down to reflect the bass sound into the ground. I'm concerned this would potentially ruin the sound in my yard.
3. build a short wood wall behind the rock speaker (I have extra wood from building the existing wood fence which has 5/4"x4" pickets that I could use to build a 3' x 3' or 2' x 3' (landscape) wall?
4. make some tube bass traps and place 1 or more behind the rock speaker to try to absorb some of the bass (e.g. saw plans using 10" construction cardboard tubes used for concrete forms, filled with sand)? How high/tall should they be? How many do I need?
I'm looking for something that would weather well outside. I think the treble and mids are audible but not as bothersome as the bass which is driving a particular neighbor crazy.
Thanks for any advise you can provide.