Playing repetitve music as meditation practice The way I see it, music (like everything else?) is empty of inherent existence. This is not obvious. Plato and Aristotle believed that harmonies and rythm express/represents "charachters". Contrary to the Greek champions, I do not think musical harmonies and rythms express or represent anything in and of themselves. The "meaning" and interpretation of music is dependent on causes and conditions, dependent on its parts, and imputed by mind. Music is empty. 

My question is how this emptiness of music can be incorporated into my practice. In stead of giving up music because I want to spend my time with meditation, I am wondering if the emptiness of music might in stead and in addition be used as a "mantric device" in mediatative practice. 

Here's the idea. I play bass. Me and my fellow musicians love minimalist repetition. Some say practicing an instrument is boring because you have to to the same thing again and again, but I don't agree. I think playing the same bass line over and over (alone or with others) is giving the same experience as meditation with mantras. When you play a simple line hundresds of times, you don't have to think about playing. And after a while you don't know where the line starts and ends, it's circular. The mantra is in my fingers and not my mouth. In the end, both mouth and fingers are in the mind anyway. 

It may be a long shot, but I wonder if this way of using repetition is used as a meditation device in any Buddhist practices. What schools of Buddhism is most open to this kind of idea?
The biggest issue with music is:

you can get attached to it
can created mental recitation of the lyrics which in turn creates verbal fabrications

Hence best is to resort to more conservative meditation pratice. Having said this Richard Shankman of Metta Dharma Foundation teachers mindfulness of sound as an alternative meditation technique. Excerpted from “The Art and Skill of Buddhist Meditation”:

Mindfulness of Sound
In the instructions for mindfulness of breathing we let all other experiences stay in the background of our awareness, not forcing or pushing them away but bringing a gentle sense of allowing them to be in the background while giving some preference or predominance to awareness of our breathing. In the same way, with this practice we allow other experiences to stay in the background and we give preference or predominance to the experience of sound. You may feel a natural draw or pull to awareness of hearing, and this practice can be very calming and settling. Those for whom mindfulness of sound works well commonly report it as an easily accessible and even compelling meditation object. You may be drawn to awareness of the sounds themselves or you may be more naturally aware of the act or the process of listening or hearing.
Mindfulness of sound entails working with either inner or outer sound. Even though it may be very quiet where you are meditating, you may feel drawn to rest your awareness in listening to however many or few sounds may be present at any time. Other people hear an inner sound, a clear perception of ringing or some other sound, experienced not through the ears but in the mind. You can see if you have such an experience and if you are drawn to rest in awareness of inner or outer sound.
If you are working with mental noting, you can mentally repeat hearing or sound if that helps keep you stay connected and centered with the auditory experience. If you practice mindfulness of sound, just substitute hearing every time I use the terms breath or breathing.

Since you seem to like music the main question would be how you can do this without attachment in order to make this effective, i.e., using music as a means to meditate.

Also perhaps the following might might help you (thanks to @ThiagoSilva for point out): Indriya Bhāvanā Sutta