Chances are that the noise is disturbing other residents.
I recommend that you make up a petition to have the tenant refrain from playing his/her guitar on the premises. Have the other neighbors sign it and then approach the management company again.
If you are a good tenant, your landlord won't want to lose you.
Ask the tenant to come into your unit to hear the problem. Also suggest he please put a layer of foam rubber or sheet of sound barrier to put under the loudspeakers. This will soften the vibrations in the floor.That is what you are hearing.This will help if the tenant will at least try to be considerate .
Judy is correct.....it's likely that you can make a "bigger noise" by acting as a group. File your complaint with the local police department and keep doing so until you get action.
This is a vulgar form of noise pollution and should not have to be tolerated by anyone.