4 ms·
Nowadays it’s not an issue as much since the advent of digital seat-back entertainment but often, listening to analog passenger aircraft audio loops you can hea
by tedd4u 5y ago
Nowadays it’s not an issue as much since the advent of digital seat-back entertainment but often, listening to analog passenger aircraft audio loops you can hear the 400Hz come through. 400Hz is noticeably sharper than G but between G (392 Hz) and G# (415 Hz) on the standard musical scale (A = 440Hz). So the 400 Hz clashes with everything.
- bonzini 5y agoIs this a standard or does it only apply to one aircraft maker?
- kens 5y ago400 Hertz is the standard for aviation; it allows smaller components than 50 or 60 Hertz. For military aviation, the spec is MIL-STD-704.
- tedd4u 5y agoHey Ken! Thanks. Yep that spec (dated 6 October 1959) says: 4.1.1 A-c power. The a-c power system shall be a 3-phase, 4-wire “Y” system, having a nominal voltage of 115/200 and a nominal frequency of 400 cps. The neutral point of the source of power is connected to ground (see 3.2), and the ground is considered the fourth conductor. and 5.1.5 Steady-state frequency. The a-c power systems frequency shall be maintained at 400 ± 20 cps for steady-state operation.