To be fair, we live in an older multi-unit apartment where noises travel all too easily between walls and through floors even when listening to moderately loud music. Our bare floors would echo any music or television turned up beyond "3" on the dial, and ever since our movie night party foul, we've been extra careful about how high we turn things up. Ironically, the music that causes the most issue isn't our staple of rock bands, hip-hop tracks or 60's soul. The genre of music we'd have to most closely monitor was classical music, which we like to listen to at louder volumes, and which often presents compositions with very quiet interludes interjected with dramatic notes to inspire valkries and their ilk to take to the skies.
So what's an apartment dweller to do when you like to listen to music at volumes beyond careless whispers levels, easily discern movie dialogue without resorting to lip-reading, and not impose any unintended shared...ahem..."other" sounds down or across to neighboring dwellers?
How to Dampen Acoustic Volume Inside an Apartment:
1) Cover Your Floors: If you live in an apartment with hardwood floors like we do, the best investment you can make in reducing noise levels, both outgoing and to a certain extent incoming, is to add rugs to the floors. And the thicker the pile the better. We've had both Target and IKEA rugs in the past, but they tend to be a bit thin in texture and quality (plus our cats liked to pull out chunks of the rug regularly)
Nicer quality rugs can be super expensive, but as longtime fans of FLOR carpet tiles, we recommend this flooring option to every one of our apartment renting friends who live upstairs with hardwood flooring for reasons both acoustic and aesthetic reasons. Since you can purchase them in small batches according to budget, match them to any size room, and even mix and match, they're a superior option to a single rug.
We recently fell in love with one of their latest designs, Just Plain Folk, a 100% recycled nylon fiber design which not only looks cozy, but killed the echo in our living room so we can turn up the iTunes and enjoy our Bieber...we mean...SLAYER to our heart's content. FLOR representatives mentioned though they cannot endorse their products as sound dampening solutions, there have been some customers who have even applied them as acoustic wall panels to reduce higher frequency sounds. Whether FLOR, carpet or traditional rugs, remember thicker is better when it comes to sound dampening.
2) Apply "Acoustical Wallpaper" onto your walls. If you want to get serious about dampening sounds without having to rip out the walls, dB2-4Walls wallpaper can supposedly reduce noise up to 75%. Installation appears to be moderately involved, requiring skills just above installing regular wallpaper, but is going to be best done with a buddy, since it's quite hefty stuff (we've got a sample of it and it's a lot thicker than the website makes it seem like). And besides the acoustic dampening characteristics of this recycled material, non-PVC, moisture barrier, mold resistant sheeting is designed to be painted over. Parents might also like lining their nursery with "Acoustical Wallpaper" so baby can get their 50 winks.
3) Fill and Furnish Your Room: Ironically, the more stuff in your apartment, the less noise will be noticeable emanating from your Dance Party USA. So add curtains, wall art, floor pillows, and other decorative elements and furnishings. If you're even more serious, you can install some acoustic curtains such as STC 13 Quiet Curtains, rater to reduce noise by 13 decibels.
5) Keep speakers away from walls you may share with neighbors. This also means keeping audio equipment like speakers and subwoofers elevated so sound travels more directly across and not downward. Seems obvious, but a great many people setup their systems without regard about how it may sound beyond their own walls.