Not familiar with Holy Wave but I will take your word!
It looks like they took the full album off of their bandcamp page in anticipation of the physical release, but here is a link to a song:
http://holywave.bandcamp.com/album/knife-hitsThey play pretty straight up psychedelic rock. They have been in heavy rotation since I randomly found them while researching the smaller bands playing at this year's Austin Psych Fest (Which I still might attend).
I can't believe they're putting it on the backstage. It needs to be on the mainstage (correction: it needs to be on the Verizon Center stage but I Am Not In Charge) but whattyagonnado.
Its probably on the backstage because not everyone gets as excited about this kind of music as they do for most other genres. I'll be there, and I for one am glad they are having it in the backstage area. I definitely prefer smaller to bigger venues to see a band.
You might dig Holy Wave, they pretty much kick ass.
Speaking of Black Cat shows:
4/13 - CLOUD CULT