Link: Time stretch only
_______________________________________________
Figure 92 : The first section is altered as shown in figure 93. The second section of the sound file is unaltered. The third section is altered as shown in figure 94.
Before digital audio was manipulated with computers, and audio engineers were using analogue tape machines, it took longer to change pitch or time in a song, without re-recording it, because they couldn’t change one without changing the other. I’ve read stories about Alan Douglas working on posthumous Jimi Hendrix recordings and literally cutting the tape into 1/4 inch pieces to extend notes.
Figure 93 : Cool Edit 2000 control settings for the time and pitch stretch effect. The sound starts out faster then normal and higher pitch than normal and ends with normal, unaltered, pitch and time.
The time and pitch stretch effects in Cool Edit 2000 can change both time and pitch, just time (preserving pitch), or just pitch (preserving time). This is done by resampling the sound file ; the computer mathematically recalculates sound volume and frequency information.
Figure 94 : Cool Edit 2000 control settings for the time and pitch stretch effect. The sound starts with normal, unaltered, pitch and time and ends with lower than normal pitch and slower than normal time.