A form of magnetic tape audio recording in which the recording medium is held on a reel. the supply reel or feed reel containing the tape is mounted on a spindle; the end of the tape is manually pulled out of the reel, threaded through mechanical guides and a tape head assembly, and attached by friction to the hub of a second, initially empty take-up reel. Tape was the first recording medium that allowed a recorded performance to be spliced or edited, and manipulated physically. The performance of tape recording is greatly affected by the width of the tracks used to record a signal, and the speed of the tape. The wider and faster the better, but of course this uses more tape. These factors lead directly to improved frequency response, signal-to-noise ratio, and high frequency distortion figures. Generally, the faster the speed the better the sound quality. Slower speeds conserve tape and are useful in applications where sound quality is not critical. Typical tape speeds are15/16 inch per second (ips), 1 7/8 ips, 3 3/4 ips, 7 1/2 ips, and the professional studio tape speeds of 15 ips and 30 ips. 30 ips is used where the best possible treble response is demanded, such as in many classical music recordings. Tape can accommodate multiple parallel tracks, allowing not just stereo recordings, but multi-track recordings too. The first multi-tracking recorders had four tracks, then 8, then 16, 24, and so on. It was also discovered that new effects were possible using multi-tracking recorders, such as phasing and flanging, delays and echo, and these innovations appeared on pop recordings shortly after multi-tracking recorders were introduced.