So - the noise level in what will be the library/piano room is acceptable (thanks to the anti-noise double glazing), but I'm looking forward to gain every dB of silence I can. Not sure of whether I will install curtains - from what I understand, even lined curtains may not help that much (and for them to help at all, one needs to use a single panel with velcro on the sides... I wonder what my gf will think of that).

 

I haven't noticed any cracks or empty space around the window frame, but one can never be too sure. So, I've just been looking for acoustic sealant - to find, to my surprise, many kinds and brands of sealant, just not any (in France) that is specifically branded as acoustic sealant.

 

Is all sealant created equal? Should I just be looking for any tube of sealant (with one of those Spanish-Inquisition devices for getting the sealant out of the tube)?

low modulus silicone suitable for glazing. like soudal lmn. then some caulk round the inside.

I hear compriband is considered top notch above any mastic sealants. Worth an investigate.