Yeah, but since meditation is nothing more than observing the thoughts that come into one's head without identifying with them on an emotional level, it doesn't actually matter if the mind is clear of words. Meditation does not preclude the activity of the brain, surely you're not saying that?
With music, it's not about the music coming in. It's not about anything coming in. It's just about if the mind can stop thinking. If you're so concentrated on listening to the music, that it osmotes into you, and your whole brain activity is focussed on your experience of the music, then i would say that is meditation.
As I have been taught meditation, which has usually been Buddist influenced, I was advised in the early stages to bat away any thoughts that entered my head - not get upset over them being there (for that would be to engage in them) but to gently push them away and go back to your counting, or candle, or whatever simple icon you might be using.
Eventually, with practice, you don't have to do that anymore - the thoughts cease when you start meditating. It can take months to reach this point, and for some people it never comes.
But the training method of focussing on something natural and simple, like a candle flame, or your breath, or your naval, gives you a white page (a white noise even, if it's water) against which you can spot if something enters that shouldn't be there.
This separation of the thinking and the unthinking mind is the first step to controlling the unthinking mind, to try and reach the level where you can enter the unthinking mind on the bus, in a queue, with many distractions around you, at any time you want.
Music, however, is a complex, man-made thing. It's purpose is to emotionally engage you; even a single G chord changing to a C chord can create an emotional response, which is not what meditation is about.
I don't think you can fully concentrate with one mind, on your breathing, if you are listening to music, and Buddhist meditation doesn't use music. I know new age 'relaxation' meditators use 'relaxation' music - but I don't think their goal is strength through peace, or Nirvana, or even transedence, as much as a really refreshing rest.
If you are in a trancendant state, then it wouldn't matter if the music was there or not, because you would have the ability
not to listen to it - but without training, most people can't reach this state - and that's why the baby slopes of meditation are littered with candles and breathing - as tools to help you switch off the outer world.
I love music, and it was through musical meditation that I became interested in the skill of meditation as a whole - so I can see why people link the two, because I did. But I've since discovered that the self-changing powers of meditation really lie inside you at all times, and outside influences always, in my experience, disrupt that journey.