What Is Parametric EQ? Android Audio DSP Explained (2026)

Open any serious audio tool — an equalizer on Android, a mastering plugin in Pro Tools, a channel strip on an analog console — and you'll see two flavors of EQ: graphic and parametric. They look different, they're used differently, and they produce different results. This post explains what parametric EQ actually is, how the math works, and when you want one over the other.

Graphic EQ: fixed bands, one knob per band

A graphic equalizer is what you grew up with on car stereos and boomboxes. It hands you a fixed set of frequency bands — usually 5, 10, 15, or 31 — and lets you push each one up or down. 31-band is the pro-audio standard because each band is one-third of an octave wide (e.g. 20, 25, 31.5, 40, 50, 63, 80, 100, 125 Hz…).

Under the hood, every band is still a biquad filter, but the frequency and bandwidth are fixed. You only get to adjust gain. That's why it's "graphic" — the sliders draw the frequency response.

Good for: quick tonal adjustments, listener-facing presets, and when you don't know exactly what you're correcting.

Parametric EQ: three knobs per band, infinite precision

A parametric equalizer also uses biquad filters, but each band exposes all three parameters:

• Frequency (f): which Hz the filter centers on. Continuous — pick 2847 Hz if that's where your correction lives.
• Gain (dB): how much to cut or boost.
• Q factor: how narrow or wide the filter is. High Q = surgical notch. Low Q = gentle shelf.

That third parameter — Q — is the whole point. With graphic EQ you're stuck boosting the whole 8 kHz band when maybe your headphones only have a 500 Hz-wide spike at 7.9 kHz. Parametric lets you hit exactly that, nothing else.

Biquad: the filter behind both

A biquad (biquadratic) filter is a second-order digital filter defined by five coefficients. The difference equation is:

y[n] = b0·x[n] + b1·x[n−1] + b2·x[n−2] − a1·y[n−1] − a2·y[n−2]

Those coefficients are derived from type (peaking, low-shelf, high-shelf, low-pass, high-pass, notch), frequency, gain, and Q. Every sample passes through the filter and comes out shaped. The math is fast enough that Android can chain 31 of them per channel at 48 kHz with under 1% CPU on modern SoCs.

Enhanced EQ's DSP runs native biquads on Android's audio thread, so latency stays under 12 ms round-trip — inaudible for music, safe for gaming.

Q factor: the knob most people ignore

Q controls filter width. Technically Q = fc / bandwidth, where bandwidth is measured at −3 dB from the peak. Practically:

• Q = 0.5: very wide. Affects almost two octaves. Use for broad tonal tilt.
• Q = 1.0: standard, about one octave wide. Default for most musical corrections.
• Q = 2.0: narrow. Half-octave. Use for specific resonance problems.
• Q = 5+: surgical notch. Room modes, feedback frequencies, hiss lines.

A rule of thumb: boost with low Q (sounds natural), cut with high Q (surgical). Our ears are more forgiving of broad boosts than of narrow ones.

When parametric beats graphic

1. Headphone correction. Measured deviations from target rarely land on graphic-EQ band centers. Parametric lets you place the correction where the dip actually is.
2. Notching resonance. Your room has a null at 73 Hz? A 31-band graphic can only touch the 80 Hz band. A parametric can land at exactly 73 Hz with Q = 4.
3. Vocal presence. A 3 kHz boost with Q = 1.2 sounds like clarity; the same boost at Q = 0.3 sounds like shouting.

When graphic is fine

• You want quick tonal shifts ("bassier", "brighter") without thinking about frequency math.
• You want a preset that's legible to other people — 10 sliders are easier to hand off than 3 floating filters.
• You're fixing a broad tonal imbalance, not a narrow defect.

What Enhanced EQ gives you

Enhanced EQ ships with both. Toggle between a 10, 15, or 31-band graphic equalizer for quick tonal control, or switch to the parametric module for unlimited filters with full frequency, gain, and Q control. Both run the same native biquad DSP under the hood, applied system-wide — every app, every output. No root required.