The Northern Line is particularly noisy - I suppose because it's the line which has most parts actually underground (see Line Infrastructure section here). Parts of the Jubilee Line are really noisy - specially the Jubilee Line extension bit from Waterloo to the East End. Any other contenders for noisy parts of the system?
However, ramping up volume to compete with the noisy London Underground, appears to be no joke as "experts" in Australia have just reported the following: "Sydney's National Acoustic Laboratories found a quarter of personal music system users in a random sample listened to music at dangerous volumes.", said the BBC and a number of other news sources in the UK.
Also "A recent study by the Royal National Institute for Deaf People (RNID) found 39% of 18 to 24-year-olds listened to personal music players for at least an hour every day and 42% admitted they thought they had the volume too high.
The RNID regards 80 decibels as the level at which hearing is threatened - 20 less than a pneumatic drill.
Some MP3 players can reach 105 decibels. EU iPods have a sound limiter to comply with noise safety levels, however sometimes users hack through this in order to listen to it louder."
And they're with me on my London Underground noise theory too "RNID has been concerned for some time that many people are turning up the volume on their personal stereos to levels that could create hearing loss in the long term.
"This is precisely the case when attempting to drown out unpleasant noise from traffic and on the Tube."
Anyway the RNID have launched a microsite and campaign called "Don't Lose The Music" to urge us to be aware of the risks so we can continue to enjoy music for longer.