What earphone manufacturer tags " sensitivity " parameter is very similar the sensitivity parameter of sound box, to sound box, its standard is: Supply 1W is apart from in 1 meter, measure its sound pressure level next (SPL) ; To earphone, its standard is: Supply 1 fine long hair is made of baked clay (1 fine long hair covers with tiles = 1/1000 covers with tiles) , the sound pressure level that measures stethoscope next (use a false head, buy mike is measured inside) . Sensitivity is earphone the DB number that produces actual sound pressure level when 1mW is inputted; Earphone manual can mention this parameter normally, but used the DB/mW that makes a person misunderstand easily, their actually true means: When 1mW is inputted, number of gets sound pressure level is how many DB.

Careful thought takes an examination of the definition of sensitivity to reach:

Earphone sensitivity is use 1/1000 covers with tiles; What sound box sensitivity uses is 1W. Reach an experience regulation is very quickly then: You need 1/1000 power to go only drive earphone is equivalent to drive your sound box, the sensitivity that premise is them is be like (about 90dB-110dB) . Illustrate: If your HI-FI result is put,be 65W, so it is OK that you need 65mW only the earphone with corresponding drive (the likelihood that actually you need is little at 65mW, the sound box that because can be in 1 meter of place without the person,listens to them) . You can discover HI-FI radio - , the power output that their earphone exports a mouth to offer 10-20mW only normally, actually its practice is correct.

Additional, think those portable recorders, they sound very loud, very noisy. Oh, you can be in 10 feet even outside hear. Output of how many power does it have? Have 12mW only probably.