Generally a mono amp is a single channel amp that means the amp plays the sound without any characteristic directionality like the left versus the right. Mono amp can be very useful in some certain system.
The first difference between the a mono and a multichannel amp is the price, mono amps are cheaper than the multichannel amps, because multichannel amps produce better and fuller sound at moderate levels.
To compare those amps you can turn up the bass. When the bass is dominating, a mono amp sound aren’t all that distinguishable from the multichannel amp.
Check both amps impedance level also. A typical mono amp run on 2 ohms, meaning they are compatible with any speaker system or subwoofer with multiple of 2 impedance, but for systems that run on 4 or 6 ohms you’ll need an extra wiring. A multichannel amps run from 2 ohms and above.
In a moderate volume levels the mono amp will produce a muffled quality, and a multichannel amp reproduce a lighter and fuller sound. The mono amp are not fit for surround sound systems.
The mono amp are perfect for simple speaker system who would like to have a lot of bass playing. It is also cost effective because it is cheaper with a sound quality at bass tones dominating systems.
