The following talks about the definition of "high fidelity".
It seems that, apart from a semi-successful attempt at standardization in 1973 by
the German Deutsches Institut für Normung (DIN), called DIN 45500, there is no
official definition for hi-fi. Here is my own somewhat vague definition:
- Wide bandwidth is the first and main target of this project because
it is so lacking in most electric guitar setups. A common specification for hi-fi
is 20 to 20,000 Hz bandwidth. Few humans can hear much outside of this range.
- Flat frequency response. In other words perfect equalization - no peaks or valleys
in the transmission spectrum. A related property that applies to magnetic guitar pickups is "to what
length of the string does the pickup respond?" A big full-sized humbucker, for example, will
pick up a couple of inches of the string. Upper harmonics of a guitar note
have standing wave lengths under a couple of inches. Those standing waves will produce opposing
electrical voltages in the pickup coils, killing many harmonics and creating holes in the audio
spectrum. An interesting note here - check out Ron Hoag's optical pickup on
YouTube. This is probably more hi-fi than any magnetic pickup.
- Low noise. Usually heard as hiss or hum, and more noticeable at low signal levels.
Noise measurements may be frequency-weighted by the ITU-R 468 curve.
The noise level of an amplifier is often expressed as "input-referred noise". This is the noise
level that would be required at the input to produce the noise level measured at the output.
- Low distortion. Often stated as total harmonic distortion (THD) or signal-to-distortion ratio.
This is heard as a buzzing sound, and is usually more noticeable at high signal levels.
Overdrive distortion is a good example. The input signal level for this measurement should be stated.
Distortion measurements may also be frequency-weighted by the ITU-R 468 curve.
