kb/data/en.wikipedia.org/wiki/Sending_loudness_rating-0.md

title	chunk	source	category	tags	date_saved	instance
Sending loudness rating	1/1	https://en.wikipedia.org/wiki/Sending_loudness_rating	reference	science, encyclopedia	2026-05-05T11:53:28.664698+00:00	kb-cron

The sending loudness rating (SLR) is a measure of the loudness of the transmit audio sent through the microphone of a communication device (for example, a mobile phone) It compares the Sound intensity of the sound waves into the microphone to the resulting audio signal. It is measured in dBV/Pa. For telephony, the reference sound pressure level is 20 micro-Pascals, with values in dB referenced to that value. 20 micro-Pascals is called the Threshold of human hearing, and is equal to 0 dB Sound pressure level (SPL). ITU-T recommendation P.79 has the frequency weighted sensitivity calculations in it for sending loudness rating (SLR) and receive loudness rating (RLR) for telephony.

== References ==