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Old Book

audio basics

technology evolution

calculations and more...



Experiments in capturing sound on a recording medium for preservation and reproduction began in the 1800s. Many attempts to record and reproduce sound were made during the latter half of the 19th century – and these efforts resulted in the invention of the phonograph by Thomas Edison in 1877.

A PA system may include multiple microphones or other sound sources, a mixing console to combine and modify multiple sources, and multiple amplifiers and loudspeakers for louder volume or wider distribution. PA over IP refers to PA paging and intercom systems that use an Internet Protocol (IP) network, instead of a central amplifier, to distribute the audio signal to paging locations across a building or campus, or anywhere else in the reach of the IP network, including the Internet. Network-attached amplifiers and intercom units are used to provide the communication function.

100 V line technique simplifies entry into the field of PA applications
It is not quite easy to understand the concept of Public Address. Basically, you have 2 components, special 100 V speakers and respective amplifiers. You simply add up the power ratings (watts) of all connected speakers and select an amplifier which provides at least that amount of power in watts. You can use thin cables and connect speakers over large distances with the same connection without risk of line loss and performance loss.

For paging of staff members there are several options available depending on the type of audio system that’s being installed.

With a standard 100V line system, paging from the main unit can be done using a standard microphone, with muting of any audio playing whilst the talkover function is in use. Factories tend to have high ceilings and few internal walls, so the speakers to be used need to be carefully considered. Usually wall speakers are mounted in bays and packing areas, while horn or pendant speakers with a larger range are used in big open spaces.

What is the speaker and amplifier power required? How to calculate the  distance and sound pressure level?

Explanation of Audio amplifier Speaker solution,  SPL Calculator in a distributed sound system.

If your audio system has a hum or buzz coming from the loudspeakers, there are several easy steps you can take to discover what the cause and cure will be.

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