Amplifiers are needed to amplify the audio signal for driving the speakers. Power amplifiers differ from each other mainly in the number of channels and their output power (specified in watts). Professional devices for use in event technology are called PA power amplifiers. The PA is an abbreviation for "public address". PA power amplifiers are used wherever it is necessary to provide sound to large areas as uniformly as possible.
How many channels does an amplifier need?
One output device can be connected to the system on each channel - i.e. a loudspeaker such as a satellite box or a Subwoofer. A primary distinction is made between the following amplifiers:
- • A stereo amplifier usually has two output channels for connecting a total of two speakers (left and right).
- • A 3-channel amplifier is required for classic 2.1 applications with two tops and a subwoofer.
- • The zone amplifiers are primarily used in large retail stores, hotels or even restaurants. With them it is possible to control different zones with separately controllable areas. For example, you can either provide sound to all or only selected parts of a location.
How many watts does an amplifier need?
The power output of PA amplifiers is not always specified uniformly. When using less serious standards such as PMPO (Peak Music Power Output), peak values are used, but the power amplifiers can only reach them for a very short time.
For our amplifiers, however, the value is usually given in RMS (Root Mean Square). This is an elaborate and internationally recognized measurement method, which ensures a constant efficiency of the power.
As an approximate rule of thumb for the number of watts required, about four to six watts are needed per person in the room. So for a wedding with 100 guests, about 400 to 600 watts are needed. For an indoor event with around 500 people, on the other hand, around 2,000 to 3,000 watts are required for sufficient sound reinforcement.
Important: However, these are only roughly estimated empirical values.
It is crucial that the power of the amplifier matches that of your speakers. Both a power amplifier that is too strong and one that is too weak will damage the speakers in the long run.
Which amplifier fits a subwoofer?
In most cases, amplifiers with an odd number of channels are suitable for subwoofers. In practice, these are usually amplifiers with:
- • three channels for 2.1 systems
- • six channels for 5.1 systems
Furthermore, it is important that the subwoofer's power can fully develop. Therefore, it is essential to compare the subwoofer's performance data with the output power of the PA amplifier.