Sound pressure test is to prevent the earphone volume is too big to damage the human body's hearing, so the EU issued corresponding technical standards and output limits, to mobile phones, iPod and other portable audio playback equipment for testing and issue the relevant test reports and certificates. Products that do not conform to the maximum sound pressure limit of EN50332 will not be allowed to enter the EU market.

The maximum sound pressure test is divided into two parts: EN50332-1 and EN50332-2

Sound system equipment: Headphones and earphones associated with personal music players — Maximum sound pressure level measurement methodology Part 1: General method for "one package equipment"

Separate sound system equipment: Headphones and earphones associated with personal music players - Maximum sound pressure level measurement methodology - Part 2: Matching of sets with headphones if either or both are offered separately

EN 50332-1 provides player and headphones collocation is used when the maximum output sound pressure, limit is less than or equal to 100 dB. EN50332-2 provides player and headphones respective indicators: player audio output port of the maximum output voltage, limit value is less than or equal to 150 mV; headphones wide band voltage, limit value is larger than or equal to 75 mV.