My friend complaint that his MacBook Air 13" 2011 does buzz a little bit though when blasting music at maximum volume. Additionally, it does not sound as loud as he expected. It seems that something blocks the internal speaker. I helped him check out, and this is what I have found out. In this forum, some people have said that it is owing to the backlit cover which blocks the sound. I do not have the 2010 Air model, nor does my friend, so I cannot confirm this story. I inspected his laptop for a while, and then when I removed his keyboard protector, it seems that the volume is 50% louder . And it even seems that the buzz effect reduces a lot though. You have to be really anal to detect the buzz effect. It is there (of course, it is just an built-in speaker), but it is really really hard to realise the buzz effect. I inspected further, and have found out that quality of sound maybe a key factor. When playing 320 kbps quality songs, it runs smoothly. With 128 kbps songs, it only buzzes here and there at around 70-80% volume, but then at 100%, the loud volume > effect . So the morals of the whole story are: 1. Do not use a keyboard protector . 2. Do not store cheap music in your laptop .