Hi, my first post, long time professional drummer and vintage enthusiast. I just got a big collection of 70's / 80's Slingerland drums from my buddy who is moving. He was a Slingerland artist based in Chicago and sold me two custom badge Magnum Maple kits plus a bunch of other random cool drums including these 12" and 16" toms. They have ports cut between the lugs along the top rim. Were these available to the public or is this a prototype type of thing? (Sorry for the graffiti on the small tom!) They are fitted with the May special 57 internal microphones. Any ideas what they are or value? No bass drum, just the toms. I had never seen a ported one before. I'll post more pics if interested.
[IMG]https://drive.google.com/open?id=0Bz-_9nTAfdESVGxkbDd1UGFHM2c[/IMG]
https://drive.google.com/open?id=0Bz-_9nTAfdESUHgtLVJrekc5Zkk