0 Hz: DC-Offset
occurrence: Sonic shock waves, change in altitude
The DC-Offset is a displacement of an audio signal in the electrical domain. If it is to high it can kill your speakers, as your audio is not oscillating around zero, but around the point of displacement. If that happens, you hear a clip (a short noise pulse) created by your speaker.
In nature you could see the DC-Offset as a change in pressure. In that case you don’t hear anything, but just feel the pressure on your eardrum. You normally compensate it by blowing your nose or by gulping.
1 – 20 Hz : Rumble, thump
occurrence: Thunder, earthquakes, cracks in glaciers, big halls, bass drums
Rumble is produced by thunder, earthquakes, cracks in glaciers and other big phenomenons. For music and music recording there are two “instruments” that have deep low-frequencies. A bass drum, for example, emits frequencies that you can’t hear but feel. If you filter them out, you sometimes miss thump. Big orchestra halls have a sound by themselves
If you record an orchestra in a big hall, the room itself produces rumble. If you filter it, the feeling that you are in a big room might get lost.
20 – 40 Hz: Sub low, deep low, size
occurrence: bass drum, drums, bass, double bass, tuba, bassoon, piano bass synths, sub woofer
The frequency range between 20 and 40 Hz is the first one that you can actually hear. The subsonic parts of a stroke on a drum are found here. Also, the double bass and some synth basses emits sub low frequencies.
On an 88 keys piano the lowest note A0 has a frequency of 27,5 Hz. You actually don’t hear its root note, but its overtones. The most sub woofer have their lower limit somewhere in between this range. When it comes to music, you mainly perceive deep low frequencies as a pleasant feeling in your belly.
40 – 60 Hz: Fundamental, pressure
occurrence: bass drum, bass, double bass, timpani
This frequency spectrum contains the fundamental notes of most bass drums and timps. Frequencies between 40 and 60 Hz give pressure to your mix. A mix that misses this frequencies lacks a fundamental on which it can build.
60 – 100 Hz: Ground, bottom
occurrence: floor tom, cello, bass, bass drum, guitar
In this area a lot of interesting stuff is going on. 60 – 100 Hz is the range that holds the root notes of most floor toms, cellos and guitars. On a guitar, for example, the open E string vibrates around 82 per second. This range also contains a lot of crucial bass notes.
Furthermore, the character of a bass drum is defined by this frequencies. A bass drum that has its peak on 60 Hz sounds really different than one that peaks on 100 Hz. Listen to it. A mix that has to much ground sounds humming. One that has less sounds thin and small.
100 – 200 Hz: Warmth, punch
occurrence: bass, snare, male voice, guitar, viola, saxophone
Warmth and punch, how does that come along together? Frequencies between 100 and 200 Hz give warmth to bass sounds. At the same time, this range contains many root notes of guitars and the low-end spectrum of a snare. These elements give punch to your sound and are an important factor to the feeling of rhythm. Nonetheless, this qualities often clash. So choose wisely to give warmth and punch the opportunity to coexist. By the way, the deep male voice can reach frequencies down to 80 Hz, but commonly 100 – 200 Hz is the range where it has its fundamentals.