#music is the most obvious hashtag to use and with a potential audience of 55.51 million people you can see why. It does raise a question though. Is this hashtag over saturated and the answer is yes. It would be really difficult to cut through the noise on this one. Sometimes the most obvious isn't always the best. 91% of the tweets using #music are coming with links. Thats a lot of tweets wanting you to leave Twitter to look at something else.
#newmusic doesn't have anywhere near the same potential audience its partner in crime #music has but it does have some interesting insights. #music could be people tweeting about what is on the radio and their iPod where as #newmusic has a more defined audience. There are quite a lot of mentions with this hashtags which could mean other people are tweeting about new music they have heard. You could be reaching out to Bloggers, Podcasters and Vloggers using this one.
#song has 117 unique tweets every hour and only 21% of these tweets have images attached. Attaching images to your tweets statically speaking will give you more engagement. That could be key to making some traction using this hashtag.
This one is a slow burner. It doesn't have as many unique tweets per hour as some of its counterparts but it has a larger audience than #song. It would be safe to say that all these tweets are coming with a video link and this will drive engagement. Attaching this hashtag to your YouTube link could se you squeezing some extra views out of it in the long run.
I see a lot of musicians using #artist in their tweets and I would advise you to skip this one. Its too broad a spectrum to cut through. Using this hashtag you are going to get mixed in with the rest of the arts community and chances are you might get lost in the ether. It is better to be more direct in your approach than using something as broad as this. It can look appealing to using a hashtag like this to reach as many people as possible but what you really want is engagement. Its a much better strategy to use a hashtag that will get you one real follower than something that is seen by 100,000 people but with no engagement. That one follower is a potential customer.