The best room upgrade: $2250


I live in hot as hell Sunny South Florida. My house is open beam ceiling (no attic). Upstairs without air conditioning on is 95* +!

I finally got around to getting the roof Siliconed to knock down the heat and UVs= lower electric bill. What I didn't know was the impact it would make, quieting my listening/TV room. For the first time in 25 years, no traffic noise from nearby I-95 and I-595!!! And when I turned on the TV the sound was relaxed, not echoing in the room. I haven't yet put the stereo on, but will later today
Glad I did this before my Voyager amp arrives- any day now. I need to get a handle on how this changes the sound before I put in the system
tweak1
spray foam



Spray foam has a great R-value, but I would only  recommend it in conjunction with good ventilation. I see vaulted ceilings filled up to the roof decking with spray foam and condensation ruins the roof decking.
You could always move. Northern Michigan is beautiful and quiet. Our waters are shark free.
Reducing your ambient noise level is like buying a larger amplifier or a more efficient speaker, your dynamic range will increase as well as your micro dynamic detail. You will hear the breath between the singers words, the fretting of the guitar, and the hammer hitting the strings on the piano, etc. It is amazing how treating your space can pay such huge dividends with so little outlay of cash.
Much less expensive than other treatments, try getting a dozen or two of artificial ficus trees.  5' and 8' as leafy as you can find.  I have purchased a lot of artificial ficus from At Home stores.  The 5' trees are only $40.  The 8' are more expensive, but I can't remember their price.  

They are very effective diffusers and have improved every room where I've heard them used.