All About EQ Curves and Musical Styles

All About EQ Curves and Musical Styles

Look at the following curves, then decide for yourself whether certain styles of music have a “signature” EQ response.

by Craig Anderton

When you analyze music with a spectrum analyzer, you might be surprised at what you see. For example, with a bunch of music that belongs to the same musical genre, you’ll start to see a pattern with respect to how energy is distributed over the frequency spectrum. Although it’s impossible to generalize for all types of music within a genre, there are often recurring similarities that can be pretty interesting.

The curves shown in this article were researched by Har-Bal (www.har-bal.com), a company that makes EQ-oriented mastering software. Among other features, Har-Bal allows displaying “reference curves” if you like a particular sound, and want to see how your master differs from it.

In the process of developing Har-Bal, the company thought it would be helpful to include typical frequency response reference curves for different types of music. Analyzing them yields some interesting clues about EQ’s relationship to style; in all of the following examples, the upper (yellow) curve shows peak power, and the lower (red) curve shows mean power.

DANCE/TECHNO

Fig. 1: Here’s the spectral response curve for a typical techno song. Note the “bump” around 80Hz, which indicates a strong kick drum and bass.

In Fig. 1, the hyped low end around 80Hz corresponds to the strong kick and bass line. There’s a slight dip at 5kHz, but then the response climbs up again in the treble range to give presence and sizzle. This results from the accented high-hat and percussion parts, which help propel a song’s rhythm and is a crucial element of dance music.

The rest of the curve is relative flat, where all frequencies are emphasized. The object is to produce loud, pounding music that gets people moving on the dance floor, and that’s what this curve indicates.

CLASSICAL

Fig. 2: Classical music typically adds very little processing (either EQ or dynamics), which results in a lower amount of high-end energy.

The most distinctive characteristic here is the rapid rolloff in the treble range (Fig. 2), as you’d expect from acoustic instruments and a sound that doesn’t include thrashing symbols, synths with huge amounts of harmonics, or boosted treble for radio play. The bass bump may be a bit surprising at first, but orchestral bass drums, tympani, and double-bass contribute a lot of energy to the final sound.

ROCK

Fig. 3: Rock music tends to have a lot of energy in the midrange region.

Fig. 3 displays the strong bass typical of rock music, but note there’s also a lot of midrange action in the 500Hz-3kHz region from guitars, vocals, leads, and so on. The highs aren’t quite as hyped as the techno curve because there aren’t as many electronic instruments, although cymbals and distorted guitars can add a fair amount of high-frequency energy. As a result, there’s a more natural rolloff that resembles the classical curve, but with more high frequencies.

R&B/HIP-HOP

Fig. 4. The R&B/hip-hop curve is similar to rock, but with more lows and highs, and a bit of a dip in the lower midrange.

Like rock music, Fig. 4 shows there’s a significant midrange emphasis due to vocals and instruments such as guitar, piano, synth, etc. But also note that there’s definitely more bass (check out the energy in the kick and bass guitar/synth bass range), as well as a bit more high-energy action. The lower mids around 200-300Hz are down a bit; this generally produces a cleaner, less “muddy” sound that’s indeed characteristic of a lot of R&B and hip-hop.

FOLK

Fig. 5: The curve for folk music is quite similar to classical, which is to be expected as both forms of music favor acoustic instruments.

The curve in Fig. 5 is for an acoustic folk ensemble. As befits acoustic music without significant amounts of drums or bass, the accent here is on vocals, guitar, and other midrange instruments. Bass and treble both fall off substantially; unlike classical music, you don’t have powerful instruments in the bass range (like tympani) to contribute large amounts of low-end response.

ADULT CONTEMPORARY

Fig. 6: Although the highs and lows taper off somewhat as with acoustic music, note the high-frequency “bump” characteristic of percussion.

This is also called “new age” music or easy listening. This type of music is designed to accent melody and not produce sizzling highs or pounding basses, which Fig. 6 clearly indicates: There’s a significant amount of midrange energy, and a gentle tapering in the bass and treble regions. However, note there is a bit of a peak around 7-8kHz. This is characteristic of tunes that include bright percussion, like shaker, tambourine, maracas, and the like.

SO WHAT DOES IT ALL MEAN?

These graphs are designed to illustrate some points about spectral distribution is certain types of music, not serve as a “rule” about how music should sound. Still, as you’re mixing, it’s useful to know the characteristics of other music in the same genre, so your song can slide relatively easily into a playlist. For example, if you’re mixing dance music and you don’t have a prominent kick and some high-end sizzle, the music will sound weak when compared to other dance music.

As always, your ears need to be the final arbiters of what sounds correct. But given the importance of EQ in producing a finished master recording with a commercial sound, the more you know about what you’re doing, the better!

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 Craig Anderton is Editorial Director of Harmony Central. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.