I have done the same experimenting with songs, tones, white noise, blue noise, etc.. hell.. I have even tried death metal, although I would not really recommend that.  I like most anything that contain no lyrics. I like Shpongle, Entheogenic, Desert Dwellers and other music like that for my DMT travels.  I also enjoy classical music. Shpongle Spores is an amazing song to listen to on DMT IMO. The first time I ever did DMT I was listening to Ocean by John Butler, that song has a very special place in my heart.

I think music can act very much the same way that icaros do, they ground us and can open up portals as you put it, they can drive the experience, interact with it and can create visuals, emotions and guide us through unimaginable landscapes.  Sound tracks for hyperspace drives.