Although there are many audio applications and media that can be used to play music on your Mac, iTunes is still the most popular choice in the management of musical content.
iTunes offers the ease of controlling the sequence of music, create playlists, and play music, it also has a very useful feature, the sound quality setting facility.
To be able to adjust the sound quality, you need to activate the Sound Enhancer which can be accessed on the iTunes preferences, where there Playback window.
In the Playback tab there is a check box that says Sound Enhancer. Put a check in feature.
Sound settings can not only adjust the treble and bass sounds, but also change the channel for stereo quality sound.
In addition there is a rarely used feature of Mac users, the iTunes equalizer, serves as a regulator of the depth of sound frequencies that can raise the quality of the music.
Here are some explanations about the depth of sound frequencies as reported by cnet.com.
32Hz: Suitable for loud noises like the sound of beating drums.
64Hz: Bass voice rumbling like the sound of a gong.
125Hz: For low-noise bass instrument of any kind.
250Hz: To enhance the sound coming from the piano, guitar, cello, etc.,
500Hz: Heavy sounds like the singer Barry White and bass instruments.
1kHz: The frequency of the singer’s voice is quite influential.
2KHz: Most of the singer’s voice fit at this frequency.
4KHz: Suitable for melodic sounds such as guitar solos.
8KHz: Cymbal sound or the sound of an electric guitar strokes fit at this frequency.
16KHz: High voice that sometimes rupture can be handled with a depth of these frequencies.