Soundproof windows are built on these principles. They use materials that could take in sound or result in it being reflected. Batt insulation is Alright also. Minimize the insulation to suit, and use non-permanent adhesive like duct tape to hold it in position. You can find a problem between Cloudflare's https://josuegyobm.kylieblog.com/30421762/acoustic-window-solutions-fundamentals-explained