Nowadays, thanks to the development of audio technology, it is possible—and useful—to add sub frequencies to an audio source. Since human hearing is not that sensitive, when a sound reaches a range below 20Hz, audiences tend to feel the noises rather than hear them.Today, however, it is possible to recover sub frequencies to certain musical instruments.
A Brief Reminder
The audio spectrum is the audible frequency range at which human beings can hear. This audio spectrum range spans from 20Hz to 20,000Hz and can be classified into seven frequency bands. Each band has a completely different impact on the overall sound.
Sub Frequencies: Sub-bass
The sub-bass offers an extremely low frequency, usually felt more than heard. This frequency ranges from 20Hz to 60Hz. Many musical instruments have difficulty entering this range. Professional users apply very little equalization because too much boost in the sub-bass range can transform a common sound into an extremely powerful one. When the opposite happens, the sound weakens.
The bass ranges from 60Hz to 250Hz and it determines the width of the sound. The most essential notes of rhythm center on this area. When the sound is closer to the high end of the spectrum, audiences perceive the tones as warmer. Too much boost can translate into loud deep sounds.
Sub Frequencies: the Ranges
The low midrange goes from 250Hz to 500Hz and includes the low order harmonics. When the high signal is higher, the perceived sound is clearer. In contrast, audiences can perceive too much boost in this area as an obstructed sound. The midrange varies from 500Hz to 2kHz and determines the importance of a specific instrument in the overall mix. At around 1000Hz, sounds seem to have a horn-like quality.
Moreover, excess output can translate into a dispersant sound. The upper midrange goes from 2kHz to 4kHz and can alter sounds with the slightest boost. You have to manage enhancements at this range very carefully because they can add presence at some point. In addition, they can cause ear exhaustion if boosted excessively.
The presence range goes from 4kHz to 6kHz and it is related to the clarity and definition of a specific sound. If boosted excessively, the sound tends to turn harsh. In opposition, if it reaches the other end of this spectrum, audiences might perceive this as transparent and distant. The brilliance range, which goes from 6kHz to 20kHz, includes only harmonics and is offers sparkle and air to any given sound. over-boosting can translate into a sharp sibilant sound that is not quite pleasant for the human ear.