I would consider these to be Quad, although they came out after Quad was killed by the record companies and equipment manufactures. They were intended for musicians to make multitrack masters. I don't know why someone would opt for one of these for that purpose, a reel to reel would be much better. At 3 3/4 ips and 4 tracks you wouldn't have a lot of playing time and the tapes would not conform to Philips original standard.