I've found insulation like rock wool decent for muffling general noise, but honestly, voices—especially higher-pitched ones—still slip through pretty easily. If you're dealing with karaoke nights regularly, might wanna look into adding acoustic panels or sealing gaps around outlets and doors...that helped me a ton.
Totally agree that insulation alone won't fully block voices, especially higher frequencies. Rock wool is great for general noise reduction, but voices tend to travel through structural elements like studs and drywall. Acoustic panels definitely help, but you might also consider adding mass-loaded vinyl behind drywall or even doubling up drywall layers with Green Glue in between. Did this in my home office—made a noticeable difference when the neighbors had their weekend gatherings...though karaoke nights might still test your patience occasionally.
I've actually been thinking about trying the mass-loaded vinyl myself. Did you install it directly onto the studs or over existing drywall? I've heard mixed things about installation methods...some say it's easier to handle if you attach it first, then drywall over, while others suggest sandwiching it between two drywall layers.
Also, curious—did you find that adding Green Glue was worth the extra cost and effort? I've done double drywall before without anything in between, and the improvement was decent but not mind-blowing. Wondering if Green Glue really makes a noticeable difference or if it's more subtle. Karaoke nights around here are brutal too, haha...if anything can tame those high notes, I'm all ears.
I went with sandwiching the MLV between two drywall layers...honestly, wrestling that stuff onto bare studs sounded like a nightmare. As for Green Glue, I'd say it's subtle but noticeable—definitely helps soften those karaoke screeches, though sadly doesn't improve their singing talent...
Good call on sandwiching the MLV—definitely easier than wrestling it onto studs. Green Glue's subtlety is pretty common; it won't silence everything, but it does take the edge off. Karaoke screeches aside, sounds like you're on the right track...hang in there!