The speed of magnetic tape is not a single fixed value but varies significantly depending on the type of recorder and its intended application, particularly for analog audio tape recorders.
Standard speeds were established for analog tape recorders to offer a balance between audio fidelity and the amount of tape consumed. These speeds are commonly measured in inches per second (ips) or centimeters per second (cm/sec).
Standard Speeds for Analog Tape Recorders
Based on standard practices for analog tape recorders, distinct speed ranges are used for professional and home recording applications:
- Professional Use: High-fidelity recording in professional studios often utilizes faster tape speeds to capture a wider dynamic range and frequency response.
- Home Use: Consumer-grade recorders typically operate at slower speeds, prioritizing longer recording times per reel or cassette over absolute fidelity.
According to standard specifications:
- The standard speeds at which analog tape recorders play the tape are 30, 15, 7-1/2 inches/sec (ips) in professional use (76, 38, 19 cm/sec respectively).
- For normal home use, the standard speeds are 7-1/2, 3-3/4 and 1-7/8 ips (19, 9.5, 4.75 cm/sec respectively).
Summary of Standard Analog Tape Speeds
Here is a breakdown of these standard speeds:
| Usage | Speed (ips) | Speed (cm/sec) | Common Application |
|---|---|---|---|
| Professional | 30 | 76 | Mastering, High-Fidelity Recording |
| 15 | 38 | Professional Recording, Studio Production | |
| 7-1/2 | 19 | Semi-Professional Recording, High-Quality Home Use | |
| Home | 7-1/2 | 19 | High-Quality Home Recording |
| 3-3/4 | 9.5 | Standard Home Recording, General Audio Use | |
| 1-7/8 | 4.75 | Dictation, Extended Recording Time (Lower Fidelity) |
Why Does Speed Vary?
The choice of tape speed involves a trade-off:
- Faster Speeds (e.g., 30 ips): Offer superior audio quality, better high-frequency response, lower noise, and less print-through. However, they consume tape rapidly, meaning less recording time per reel.
- Slower Speeds (e.g., 1-7/8 ips): Provide much longer recording times on a given amount of tape but result in reduced fidelity, poorer high-frequency response, and increased noise.
These speeds were particularly relevant for reel-to-reel analog tape recorders, though variations existed for other formats like 8-track cartridges or cassette tapes (which typically ran at 1-7/8 ips). The standard speeds mentioned are foundational to understanding the capabilities and limitations of classic analog magnetic tape recording.
