Graphic equalizer demonstration using the Waves GEQ Classic
With a modern plug-in parametric equalizer it is possible to achieve almost any EQ curve that is required. It is also easy and quick to set. So the question is why would you choose to use a graphic equalizer in the digital audio workstation environment? This video helps demonstrate.
Automated transcript
With a modern plugin parametric equalizer it's possible to achieve almost any EQ curve that's required it's also easy and quick to set so the question is why would he choose to use a graphic equalizer in the digital audio workstation environment partly the reason is very subjective similar to the way in which a guitarist would choose which of his or her guitars to play on a particular song it's more of an instinctive feeling than a considered thought but also there are EQ curves to which the graphic equalizer seems naturally more suited than the parametric here we will consider some of the options corrective EQ firstly I'll set a curve on the graphic equaliser to compensate for a less than perfect frequency balance the original track rock by m RB 38 in a short extract sounds like this
and with the graphic equalizer plug-in inserted set to flat
this is the waves geq classic which emulates a traditional third octave hardware graphic equalizer like the clock technic dn 360 the third here means one third not the next after first and second the main difference is between this and the traditional hardware equalizer are these the input and output meters the spectrograph display showing the left channel input in yellow the right channel input in blue and as we shall see in a moment the response curve of the equalizer a little confusingly also in blue the range of the slightest is switchable plus or minus six plus or minus twelve or plus or minus 18 DB the cue of the individual bands can be adjusted from 0.25 to 4 the left and right channels can be ganged an additional parametric EQ is included settings can be stored and recalled a quick note on the spectrograph display the graphic equaliser divides the frequency spectrum logarithmically so the center frequencies of the bands of an octave band graphic EQ would double for each slider to the right in this third octave EQ each band is a third of an octave higher the spectrogram will show a straight horizontal line for pink noise which has an equal amount of energy in each third octave band this music clip has a frequency balance reminiscent of the 1970s it isn't bad but it might be considered a little dull for today's tests as you can see there is a fall-off from around 3 kilohertz upwards it isn't unusual to have a fall-off at higher frequencies but starting at 3 kilohertz is probably a little too low also you will see a boost in the bass this isn't bad and it actually sounds quite nice however for some applications where loudness is important such as traditional AM and FM radio which base content can force the overall perceived loudness to be lower reducing the base can allow the mid-range to be higher in level and the track will sound louder taking the above into account here's an EQ curve that addresses the issues it sounds like this
alternating the original and the eq'd version using the bypass control we can clearly hear the difference
tilt EQ tilt EQ is where the frequency spectrum is skewed over the full width of the audio band centered on the frequency you consider subjectively to be the center of the audio band in this case I've chosen 630 Hertz as it works well with this EQ so frequencies less than six hundred and thirty Hertz could be progressively lowered down towards 20 Hertz and frequencies greater than six hundred and thirty Hertz could be progressively raised towards 20 kilohertz the angle of the tilt would be chosen subjectively according to what sounds good this is oddly enough easier to achieve on a hardware graphic than a plug-in on a hardware graphic you can slant all the sliders evenly using a ruler or other straightedge in a plugin the process is more fiddly but the concept is the same in this example the purpose is demonstration we wouldn't necessarily say that the results sound better than the original in this case but they certainly do sound interesting here's the flat version again
and here's the same track with EQ tilted upwards from low to high
the sound is lighter and brighter it's a different effect to concentrating on the high frequencies alone or the low frequencies alone it does in fact make a point that even when using a parametric EQ if you feel the need to boost the high frequency region then it's worth considering the alternative of boosting the high frequencies around half as much and bringing down the low frequency region by about the same amount here's a comparison with the EQ alternately switched in and out
an opposite tilt will bias the frequency balance towards low frequencies this definitely doesn't sound so good in this example because the original was already a little lacking in brightness but it shows what can be done flat for reference
EQ tilted downwards from low to high
comparison
one last point is that the range between low and high in both examples is a mere two decibels this shows that small boosts are cuts that cover a wide range of frequencies can have a significant effect a two DB range is probably the most that you would need a 1 DB range can often be all that's required shelf EQ another type of EQ that suits graphic equalizers is shelf or shelving EQ normally in a parametric equalizer the low-frequency section and high frequency section would both have bell and shelf options Bell is where the EQ acts around a certain frequency shelf is where the EQ extends from that frequency all the way to the limit of the audio range although you can set pretty much any shelf EQ curve you want on a parametric EQ the graphic is more intuitive if you consider wider ranges of frequencies in this example I've chosen a midpoint of 630 Hertz and created examples where the Shelf starts immediately adjacent to that frequency in both boost and cut firstly the flat example again it's a little lower in level so that the low-frequency shelf boost later on doesn't clip
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and now I set a shelf of just 1 DB all the way from 800 Hertz to 20 kilohertz one decibel doesn't seem like a lot but over a wide band it has a significant effect
a comparison alternating EQ in and EQ out
setting the slide is 2-1 DB also has a significant effect since the original track is just a little dull in frequency balance it's best to regard this as a demonstration of the method rather than a good example of what the track should sound like
and the comparison alternating EQ in EQ out
likewise the same thing can be done with frequencies below 630 Hertz with low-frequency shelf boost the results sound stronger in the base even though the boost is only one decibel
comparison alternating EQ in EQ out
with low-frequency shaft cut the results sound significantly lighter
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comparison alternating EQ in EQ out
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individual instruments the graphic EQ can be applied to individual instruments or vocals here I'll demonstrate graphic EQ using a recording of bass guitar provided by an audio masterclass student here's the bass guitar without EQ as you can hear there's a lot of high frequency fret buzz this can be a fault or us here it can be used as an expressive effect that will help the bass be clearly audible in the mix through higher frequencies as well as low there are many occasions however where fret bus can be irritating and if a producer originally liked this fret bus but the mix engineer doesn't then EQ will be necessary to reduce it here's an EQ setting where the fret bus is reduced considerably and a comparison switching the EQ in and out but now the sound has become a little dull as with parametric EQ boosting the curve at frequencies just below the cut can help and the comparison this is probably about the best compromise achievable but much would depend on the context of other instruments in the mix another option for bass guitar is to really focus in on the low frequencies and we can do that here with graphic EQ in fact where the previous example was something of a compromise the following example could be described as bass the whole bass and nothing but the bass I'm the comparison in summary although a graphic equalizer is not essential for the music recording studio it can be an interesting and worthwhile extra to have available I'm David Miller course director of audio master class thank you for listening
David Mellor
David Mellor is CEO and Course Director of Audio Masterclass. David has designed courses in audio education and training since 1986 and is the publisher and principal writer of Adventures In Audio.
