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
Using certain types of insulation; silicon, spray foam, cellulose, etc., helps tremendously in reducing sound travel. Glad you are able to enjoy your TV and music better now. The long term benefits for heat reduction and sound mitigation  are really worth it.
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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.   
spray foam dont get that crap on your skin, acoustic treatments are great so great that I installed a Track around my room and I can have curtains all over when I want , cost me little over 1,200 the sound deadening curtains were 120 a panel and gets expensive , I picked up on amazon and there nice and heavy and do the job well and keep light out too. 
If it was spray foam insulation you used it will also extend the life of your roof shingles 
I did my attic several years ago and my attic temp went from 120+ to typically 78 degrees on a very hot day  My AC service guys love it when they have to go into my attic now, or me for that matter
To clarify, the silicone is applied on top the roof
Where I used to turn my volume in the low 60s, I can hear quite a bit at < 40
OMG, the house is so much cooler, which was the point all along
If you want to investigate I got 2 estimates, the one I chose was $2250, the other $7,000! And the $2550 job was very professionally done
OP and others, thanks for all the useful and interesting information. Incidentally, we are in the process of getting our roof deck foamed for better energy efficiency in our hot, Phoenix summers. Never thought that better sound would be icing on the cake. Now I'm even more motivated.
For those that don't want the expense of a spray foam attic or silicone application, you can add an attic fan The one l have is controlled by my smart phone  It lowers my attic temp from the 120's to high 80's but there is the additional electrical cost to consider
These ideas should be thought of as room treatments as much as insulation. I was originator of ambient noise levels in listening room thread, more evidence for how minimizing that can improve the listening experience here.
Update: Im thinking the silicone set up from day one which has further improved the music.

Listened to a variety of music that I am very familiar with, including; Bonnie Raitt, Chris Isaak Heart Shaped World, Jennifer Nettles Playing with Fire, which is one of the worst recordings Ive experienced, but I love the songs. To be fair, some songs are pretty well recorded, but the title song Playing with Fire is a hot mess, but I hear so much more of the music, chorus, etc, then ever before.


Well, I finally hear a lot more of the nuances that was/were recorded. The entire sound stage has opened up in a very big way, notes are much more complete (think micro details)

OP:
Thanks for starting this thread.  I will be looking into the roof treatment.  
Lots of great posts here….

Bpoletti:

I have been trying to find fake plants for diffusion or tall reeds (for lack of a better word).  Reeds perhaps an 1/8 of an inch thick that can be bundled loosely in a tall vase or umbrella stand at first reflection points.  I saw Lars employ such at Axpona 2015 in the Raidho room.  Not had luck finding those so far, either.


I have 17” of rock wool in the ceiling, 6” in the walls. For thermal performance reasons mainly, but my architect said to cover with fire resistant burlap instead of sheetrock and I would have a recording studio quality sound to my room. He was not wrong.

I am not a fan of blown in insulation. The off-gassing fumes are terrible. It’s a petrochemical product that’s bad for the environment. 
@tweak1 now all you need is to add impact windows and you will get an insurance reduction along with further noise reduction. You won’t even hear the hurricane outside,
And so the silicone is on the outside of the roof. I certainly can see the thermal and acoustic advantages of incoming heat and sound. That certainly makes a huge difference but I don't think it makes much difference in the inside acoustics in general. You still have the same reflective surfaces albeit a more dampened planar surface which is what would make some difference but it would be interesting to measure before and after. I just finished a new room with a vaulted drywalled ceiling. Shingled roof, 2 x 12 rafters filled with R38 fiberglass batts.
I know it's going to be an issue so once we get the area rug in (concrete floor East Texas), the furniture and the system back up, we will deal with it then. Probably panels on the ceiling of some type.