Podcasting Hacks

Build a Sweet Sound

Use frequency filters to adjust your recording to get the tone you want.

You can look at sound in two ways: either in the amplitude domain, or in the frequency domain. Frequencies are measured in hertz (Hz). The lower the frequency, the lower the pitch, and the higher the frequency, the higher the pitch. All sounds have a frequency, or a set of frequencies, with an amplitude at that frequency. Amplitude filters can alter the level of your sound, and frequency filters alter the character of your sound.

Human voices are strongest between 200 Hz and 3 kHz. Men’s voices tend to have more amplitude in the low end and center a little lower in the spectrum than women’s voices. Boosting the low frequencies will add more depth and warmth to a voice, and boosting the high frequencies will add detail and make the sound more crisp.

Voices also have under- and overtones that extend into the 15 kHz range and down to 50 Hz. Cutting the frequencies to between 500 Hz and 5 kHz results in boxy, phone-style sound that feels processed and unnatural. You can attenuate signals outside of this range to reduce rumble in the low end and hiss in the high end, but you shouldn’t remove them altogether unless you are going for that boxy sound.

Table 8-1 shows a short list of the different frequencies in the human voice and the effect you get when you up the graphic equalizer (EQ) in that range.

Table 8-1. Vocal characteristics at certain frequencies

Frequency	Characteristic
200 Hz	Enhances ...