Audio spectrum between two defined frequencies — e.g. highs (4–20 kHz) or lows (20–250 Hz). Shape tone by boosting or cutting specific bands in EQ.
On set and in editing, we constantly work with frequency bands—without consciously naming them. You're editing a dialogue scene and notice: the actor sounds muffled, the voice is stuck somewhere in the lower register. That's a frequency band problem. With a graphic EQ, you then target the 100–300 Hz range and reduce it by 3–4 dB. The voice already sounds clearer, more assertive. This is frequency band work: you isolate a defined range of the audible spectrum (20 Hz to 20 kHz) and specifically alter its volume.
In practice, you mentally divide audio into three zones: Lows (20–250 Hz) contain room rumble, bass components, but also hum and motor noise—you often have to work subtractively here to gain clarity. Mids (250 Hz–4 kHz) are the core of speech and rhythm—this is where presence and intelligibility reside. Highs (4–20 kHz) bring brilliance, sibilance (S sounds), cymbal shimmer. Too much of it becomes fatiguing, too little sounds lifeless. With a parametric or graphic equalizer, you address a single frequency band or multiple in parallel. A bandpass filter isolates a very narrow zone and acts like an acoustic spotlight.
At the mic input, you use high-pass filters—this essentially cuts off the entire upper frequency band below 80–100 Hz to eliminate room rumble, traffic noise, and cable friction. In dialogue editing, you can see this immediately in the spectrogram: low frequencies below 100 Hz are often just noise, never information. In music mixing, frequency band separation between instruments is crucial—kick and bass often share the lowest zone; through phase compensation and targeted attenuation of frequency bands, you create space for each sound. Monitoring through good speakers and room acoustics is essential here—a too-soft studio or extreme proximity to walls will completely distort your frequency band perception.
Rule of thumb: Subtractive EQing (lowering frequency bands) is more precise and natural than additive boosting. Boosting also amplifies noise and artifacts. If you need a frequency band, use a wide Q (gentle slope)—aggressive peaks sound artificial and fatiguing. With a spectrum analyzer, you can see the actual energy in each frequency band—it's like an X-ray for your ears.