Post by Deleted on May 8, 2017 13:28:59 GMT
Consumer Level vs. Pro Level
"Line level" refers to the maximum (peak) level of a single audio line and today's standards were established years ago by the telephone industry.
0 dB (Zero deciBels) was established as the standard level of a telephone line which achieved two things:
1.) It put the signal above the noise-floor of hum and buzz picked up by long wires;
2.) It kept the signal below the threshold of cross-talk, bleeding over into adjacent lines.
Radio broadcast equipment was designed around the 0 dB standard because of the common inter-connections between many radio stations and telephone networks.
As high-fidelity audio evolved a +4 dB standard was adopted to improve the signal-to-noise-ratio within broadcast and recording facilities.
The trend toward better S/N also resulted in some use of a +8 dB standard.
Consumer audio equipment took a different course: because it wasn't required to drive long lines nor be connected to the telephone system, manufacturing costs were greatly reduced by employing a -10 dB standard for very short interconnecting cables.
This history is made more complex by noting the two flavors of audio circuit: balanced and un-balanced.
These audio standards are generally not well known by radio hobbyists who could benefit from a fuller understanding.
Perhaps this would make a useful presentation for an ALPB seminar.
"Line level" refers to the maximum (peak) level of a single audio line and today's standards were established years ago by the telephone industry.
0 dB (Zero deciBels) was established as the standard level of a telephone line which achieved two things:
1.) It put the signal above the noise-floor of hum and buzz picked up by long wires;
2.) It kept the signal below the threshold of cross-talk, bleeding over into adjacent lines.
Radio broadcast equipment was designed around the 0 dB standard because of the common inter-connections between many radio stations and telephone networks.
As high-fidelity audio evolved a +4 dB standard was adopted to improve the signal-to-noise-ratio within broadcast and recording facilities.
The trend toward better S/N also resulted in some use of a +8 dB standard.
Consumer audio equipment took a different course: because it wasn't required to drive long lines nor be connected to the telephone system, manufacturing costs were greatly reduced by employing a -10 dB standard for very short interconnecting cables.
This history is made more complex by noting the two flavors of audio circuit: balanced and un-balanced.
These audio standards are generally not well known by radio hobbyists who could benefit from a fuller understanding.
Perhaps this would make a useful presentation for an ALPB seminar.