Calculation of Azimuth Loss and Phase Error

When playing back a magnetic tape recording with a playback head gap not set exactly perpendicular to the tape travel direction, level losses occur at high frequencies. These are referred to as azimuth loss and indicate by how many dB the signal is reduced at a given tape speed, frequency and track width, when the playback head gap is tilted by a certain number of angular minutes (′).

After entering the azimuth error (relative to 90°), the phase error and azimuth loss are calculated precisely..
 

With a tape speed of 3.75 ips (9.52 cm/s), a frequency of 10,000 Hz

and a track width of 6.25 mm (Full-track, mono)
Gap inclination ′ ≡ Azimuth loss dB
and a track width of 2.75 mm (½-track, stereo studio)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 2.1 mm (½-track, stereo amateur)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 1.1 mm (¼-track)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB

 

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 ′ ≡ Azimuth loss dB
and a track width of 2.75 mm (½-track, stereo studio)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 2.1 mm (½-track, stereo amateur)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 1.1 mm (¼-track)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth 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 ′ ≡ Azimuth loss dB
and a track width of 2.75 mm (½-track, stereo studio)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 2.1 mm (½-track, stereo amateur)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB
and a track width of 1.1 mm (¼-track)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB

 

At a Tape speed 4.76 cm/s and a frequency of 10,000 Hz (Compact Cassette)

and a track width of 0.60 mm (stereo)
Gap inclination ′ ≡ Phase error ° ≡ Azimuth loss dB

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