Calculation of the alignment loss

When playing a tape recording with a playback head gap that is not set exactly perpendicular to the tape running direction, level losses occur at high frequencies. These are known as alignment loss and indicate by how many dB the signal is reduced at a certain tape speed, frequency and track width if the gap of the playback head is misaligned by a certain number of angular minutes.

After specifying the gap inclination (compared to 90°), the alignment loss will be exactly determined.

With a tape speed of 7.5 ips (19.05 cm/s), a frequency of 10,000 Hz

and a track width of 6.25 mm (full track mono)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 2.75 mm ( ½-track stereo studio)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 2.1 mm ( ½-track stereo amateur)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 1.1 mm (¼-track)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB

With a tape speed of 15 ips (38.1 cm/s), a frequency of 10,000 Hz

and a track width of 6.25 mm (full track mono)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 2.75 mm ( ½-track stereo studio)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 2.1 mm ( ½-track stereo amateur)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB
and a track width of 1.1 mm (¼-track)
Gap inclination of the playback head angular minutes ≡ Alignment loss dB

 
Note: Standard track widths were used for the calculation. These may vary slightly depending on the manufacturer.