Spectral Balance - ectoplasma

This chapter is about tone shaping with three broad EQ zones: low, mid, and high. Move one band at a time and listen to how the same notes feel heavy, hollow, smooth, or sharp.

Equalisation (EQ) is the process of boosting or cutting specific frequency ranges in a sound. Every sound occupies a spread of frequencies, and EQ lets you reshape that spread. The machine below divides the spectrum into three zones: low, mid, and high. Each zone has its own gain slider ranging from -24 dB to +24 dB.

The three zones map to distinct sonic qualities. Low frequencies (roughly 20-300 Hz) carry bass, warmth, and physical weight. Mid frequencies (300 Hz to about 4 kHz) contain the body and presence of most instruments and voices. High frequencies (4 kHz and above) contribute air, sparkle, and fine detail. Learning to hear these three regions separately is one of the most useful skills in audio production.

Start with small moves. A 2-4 dB change is already clearly audible and musically useful. Changes of 12 dB or more are surgical - they dramatically reshape the sound and are typically used to fix specific problems rather than for general tone shaping.

Try the Smile preset. It boosts lows and highs while scooping out the mids. This "smile curve" sounds immediately impressive on its own - wide, full, exciting. But in a mix with other instruments, scooped mids cause sounds to disappear. The mid range is where human hearing is most sensitive, so cutting it removes exactly the frequencies that help a sound stand out.

The Presence preset does the opposite: it adds a gentle boost around 2-5 kHz. This is the frequency range where vocals, guitars, and snare drums carry their clarity and definition. A small presence boost makes a sound feel closer and more articulate. This is why vocal microphones often have a built-in rise in this region.

The Center frequency control lets you sweep where the mid band focuses. At low settings, the mid band overlaps with the bass region. At high settings, it reaches into the upper-mid territory where sounds become nasal or harsh. Sweeping this control while listening reveals exactly where different qualities live in the spectrum.

Experienced engineers cut more than they boost. Cutting a problem frequency is cleaner and more natural-sounding than boosting the frequencies around it. If a sound is muddy, try cutting low-mids rather than boosting highs. The result is similar but with less added noise and distortion.

The Warm preset demonstrates this: it applies a modest low boost alongside gentle mid and high cuts. The result feels round and full without becoming boomy. Compare this to achieving the same "warmth" by boosting lows alone - the difference in clarity is noticeable.

Try each waveform with the same EQ settings. A sine wave has almost no harmonics, so the mid and high bands have little to work with. A sawtooth wave is rich in harmonics across the entire spectrum, making every EQ move clearly audible. This is why sawtooth waves are the default starting point for most synthesis and sound design work.

The human ear is not equally sensitive to all frequencies. We hear mid-range sounds (1-5 kHz) as louder than bass or treble at the same physical volume. This is why the "loudness" button on old stereos boosted bass and treble - it compensated for our reduced sensitivity at low listening levels.