Understanding PA systems

Understanding PA systems

You have determined that you need some sort of system to project your voice or music over the background noise. There are nearly an infinite number of variations of systems that you could put together. This short article will outline only the basics, and later articles will detail some potential variations. We suggest that you should always discuss your specific needs with a professional while in the design phase.

So, here are the basics. You start with your source material, which could be a voice, a CD, a guitar, a band, just about anything that makes a sound. From here, the sound goes into a preamp, which raises the electrical signal to 'line level' which is what is found internally in electrical equipment.

From the preamp, the signal goes into a mixer where it is joined with other signals. Usually, the preamp and the mixer are the same device. This mixer will also typically have a way of routing various elements of the signals to different outputs, in addition to the main stereo output.

From the mixer, there may be other outboard, signal-shaping, gear. This outboard gear may not always be part of a system, however, the more professional the system, the more outboard gear you will find.

Eventually, the signal makes its way to an amplifier. The electrical signal, which so far has been at 'Line Level', now needs to be raised to another much more powerful signal to drive the speakers. Professional amplifiers have only one control, volume.

From the amplifier, the 'amp level' signal now travels to the speakers. In the speakers, the signal creates an alternating current in the coils of the speaker, which react against the magnet. This movement is what creates the sound.

So, here is the basic flow of the signal:

SOUND SOURCE to PREAMP to MIXER to OUTBOARD GEAR to AMPLIFIER to SPEAKER.

If you have questions, post a comment and we'll get back to you!