All AMS Nightlife Music & Music Video Systems come with a compressor and limiter built-in, giving you a consistent volume with every track. This means the only time you need to adjust your amplifier is to crank up your favourite track! Most MP3 players and online music providers don’t have consistent volume levels. The same applies to CD’s where the volume varies from song to song or CD to CD. AMS Music means you don’t have to keep adjusting your amplifier.