What Is a Parametric EQ and How Does It Work?
Parametric EQ differs from graphic EQ in flexibility. A graphic equalizer provides fixed frequency bands (31 Hz, 62 Hz, 125 Hz, and so on) with only a gain slider for each. A parametric equalizer lets the user choose the exact center frequency, adjust the bandwidth (Q factor), and select the filter type (peak, shelf, high-pass, low-pass, notch) for each band. Audio engineers use parametric EQ because it can target a narrow resonance at 3.2 kHz without touching nearby frequencies.
LitLink is a free virtual audio driver for Mac, and LitLink Pro adds a parametric EQ for every app. Each app gets its own EQ with a high-pass filter, one parametric band with adjustable frequency, gain and Q, and a low-pass filter, drawn as a curve over a live spectrum analyzer. A master EQ shapes the combined sound after the per-app EQs. You hear changes while you make them.
Common parametric EQ filter types include peak (boost or cut a specific frequency), high shelf (boost or cut everything above a frequency), low shelf (boost or cut everything below a frequency), high-pass (remove low frequencies below a cutoff), and low-pass (remove high frequencies above a cutoff). Studio equalizers often have several bands; for fixing one app's sound, a high-pass, a low-pass and one well-placed band already go a long way.
How Does macOS Handle Audio Equalization?
macOS sends each app's sound to the selected output device (speakers, headphones, USB audio interface) as it is, with no equalizer in between. System Settings has volume and balance controls, but no EQ.
The Music app has a 10-band graphic equalizer in its settings, but it only affects Music playback. Chrome, Safari, Discord, Zoom, and most other apps have no equalizer of their own. Users who want equalization across several apps need a third-party tool.
System-wide equalizer apps such as eqMac and Boom 3D apply EQ to everything your Mac plays. That works well when one curve suits all your audio, for example to correct headphones. When different apps need different tonal profiles, one curve for everything becomes a compromise. Check each developer's website for current features and prices.
How Does Per-App Parametric EQ Differ from System-Wide EQ?
The distinction matters in every multi-app audio scenario. A system-wide EQ that boosts 3 kHz for voice clarity in Zoom also boosts 3 kHz in Spotify, making music sound harsh. A per-app EQ applies the voice boost only to Zoom while leaving Spotify at its natural tonal balance. LitLink remembers each app's EQ settings.
LitLink Pro picks up each app's sound on its own, applies that app's EQ, and only then mixes it with the rest, so each app's curve is independent. Users who also need per-app volume control on Mac get both features in the same window, and the per-app volume mixer itself is free.
An equalizer that works on the finished mix of all apps cannot treat one app differently from another. To EQ apps separately, the tool has to adjust each app's sound before the mix, which is what LitLink Pro and SoundSource do.
How Do You Apply Parametric EQ to Individual Apps on Mac?
- Install LitLink free from litpads.app/litlink, macOS 14.2 or later for per-app features
- Open LitLink and find the app in the list every app producing audio appears there
- Open the app's EQ shows the frequency curve over a live spectrum analyzer
- Drag the point to set frequency and gain set Q for a wider or narrower band
- Set the high-pass and low-pass filters trim rumble below and hiss above
- Turn the EQ off and on to compare your settings stay in place
The curve shows the combined effect of the high-pass filter, the parametric band and the low-pass filter. Dragging the point horizontally changes the center frequency, and dragging it vertically changes the gain (boost or cut in decibels). The Q control sets how wide the band is. The curve redraws as you drag, so you see the shape of the equalization while you hear it.
LitLink Pro also includes a master EQ that applies after the per-app EQs, on each track and on the output. The master EQ is useful for headphone correction or anything that should apply to all audio sources the same way. The two stack: the app's curve processes first, then the master curve processes the result.
What Are Common Use Cases for Per-App EQ on Mac?
Podcast listeners often struggle with inconsistent audio quality across shows. One podcast may have boomy bass, another may sound thin. Per-app EQ on the browser or podcast app lets you compensate without changing music playback in a separate app. The EQ settings for each app are saved separately.
How Does LitLink Pro Compare to Other Mac EQ Solutions?
We make LitLink, so this section sticks to what each developer publishes; SoundSource facts were checked on November 5, 2026.
Sources: SoundSource, SoundSource pricing, SoundSource manual.
A system-wide equalizer is the right choice if you want one curve for everything, for example to correct your headphones, and do not need per-app control.
SoundSource by Rogue Amoeba also offers per-app audio control on Mac. Its built-in effects include a 10-band EQ, Magic Boost and a Headphone Equalizer, and it can load third-party Audio Unit plugins per app, which is useful if you already own Audio Unit equalizers and compressors. LitLink Pro has its own parametric EQ built in, can also host Audio Unit effects, and costs $20 less.
Marcel Iseli is an indie developer, DJ, and music producer with over 20 years behind the decks and in the studio. Rooted in hip hop culture, he collects drum machines, samplers, and vintage audio gear. LitPads grew out of that obsession: decades of triggering samples on hardware led him to build the software equivalent he always wanted.