Sound pressure level in a loudspeaker box is about 20dB larger than that measured at a point one meter apart from the loudspeaker box.
・The relation between the sound pressure produced by an earphone in the ear canal and that heard before insertion show us the same situation. Sound produced by an earphone near the eardrum is larger than we imagine.
- Long listening time with loud volume makes us tired. Heavy use tends to cause hearing impairment.
- When surrounding noise sound is loud, for example in a train, your listening level becomes higher without awareness.
- The ear canal is separated from our living space. So we can enjoy listening to sounds by ourselves alone without making trouble to others around.
・Various sound qualities of earphone
- As shown below, a low-priced earphone only for getting information usually have a peak of 10dB or more in a higher frequency range like several thousand hertz. It is not good for listening to music.
- Although I would like to recommend an earphone which is devised to suppress the peak, I have to admit that it becomes more expensive because of the higher quality.
- When contact of the ear canal and an earphone is not adequate, the lower sound is decreased in quality. The degree of contact is important.
・Difference of sound quality between loudspeakers and earphones
- Since you hear a sound directly from an earphone diaphragm, you need not be bothered by ambient noises from outside. There is no distortion of the acoustic field, and accordingly the room reverberation is lost. Thus, the sound is clear, but, isn't it somewhat dry and charmless?
- When you listen to a stereo sound with loudspeakers, the sound emitted from the right loudspeaker arrives at left and right ears with a little difference both in sound pressure and sound phase. (The same relationship can be seen in the left loudspeaker and both ears.) This causes an occurrence of cross-talk.
- It is difficult to locate a sound image, created by both ears, outside your brain when hearing with an earphone.
I would like to recommend you to experience and understand the features of both earphone and loudspeaker, in order to make diverse and proper use of them
for your purpose.