The upper the OITC rating, the better a window is at reducing sound transmission. Traditional single-pane windows with Wooden or vinyl frames have an OITC of 19. Batt insulation is Alright as well. Reduce the insulation to fit, and use non-long term adhesive like duct tape to hold it set https://white-ceiling-lights03690.blog-mall.com/30451930/soundproof-windows-no-further-a-mystery