I just uploaded another image of some designs I was working on, on a post-it. Can make the 'dl' look like a boat or an anchor. Both of those could work in terms of a symbol/logo as they have symbolic meaning on a spiritual level. In other words, the symbols don't necessarily need to be music related.

The "DL" do not need to be made to look like anything. Just a really nice looking stylised DL will work. The image of post-it uploaded at 12:30 7/14/16 shows a dL where I have looped the ends of the L and gone over it a few times in pen. That is a logo that has a lot of potential on a headstock, it doesn't symbolise anything, I just like the way that sketch flows.