My office mate and I actually both bought a pair at the same time - and now we joke that people have to email us before they come in because we can't hear them. The sound is quite loud, and the sized rubber earbuds and that actually go IN your ear make them seriously noise cancelling. I would definitely NOT recommend these for outdoor running/walking/biking because they allow so little outside noise in. However, for the gym, the office, the library, etc, they are great. The sound quality is not concert quality but extremely good for mid-range headphones. Great buy for the price, just be warned that you will hear nothing from the outside world!