Pack, the study is meaning “audible frequency range” about the tone. We will examine what each frequency relates to based on acoustic musical instruments and the notes they generate. Next, we will consider what these frequencies mean in the somewhat more abstract terms-for example, what kind of sound features, apart from the tone, does it contain the range of 4kHz – 8kHz? Finally, we will see why it is essential to have a good knowledge of the frequencies when making music.
The diagrams on this page will give you a good idea of the range of frequencies that a wide variety of instruments can generate. Notice first that an octave is defined as the interval between one tone and another half or twice its frequency. Thus, if we take the example of LA4 – also known as LA440 – its rate is 440Hz. The frequency of LA3 is 220Hz, and the frequency of LA5 is 880Hz.
Remembering this relationship between frequency and musical scales is very important when you work with the tones at the ends of a typical 88-key keyboard.
The difference between the frequencies of LA0 and LA1 is the only 27.5Hz, while between DO7 and DO8, it is more than 2kHz. When equalizing, a few hertz will make a big difference when adjusting the frequency range in the low part, while in high frequencies, you have to move in higher ranges. The diagrams show how to use a logarithmic scale to handle this – the distance between the 50 and 100Hz marks is equal to the distance between 10 and 20kHz.
The diagram also reflects the range of frequencies generated by acoustic instruments, but remember that electronic devices have a much more extensive range of frequencies than their acoustic counterparts. A synthesized guitar is capable of making frequencies between 20Hz – 20kHz and beyond.
Let’s go to study the harmonics. The only sounds that contain only one frequency are pure sinusoidal waves. All other waveforms have harmonic information, understandable as a series of fainter sounds at different rates.
In the image below, Logic ‘Channel EQ’ performs a spectral analysis of a signal taken from an FM synthesizer and without equalization. Although it seems that the synth has created a lot of different frequencies, only one note was played – in this case, LA4 at 440Hz. The highest peak of the graph is centered around 440Hz, but there are significant peaks at other points. These peaks represent the generated harmonics and low-frequency elements within the synthesized sound.
Almost all the sounds you use to create your songs – acoustic or electronic, recorded live or with samples – will contain a much wider range of frequencies than what your fundamental tone might suggest. The distinctive character of each instrument comes precisely from the harmonics, and they play a fundamental role in determining what each part of the frequency spectrum means to us in musical terms.
Beyond the tone
The terms -still and quite abstract- that we use to describe the different frequency ranges are instrumental when it comes to equalizing. For example, you could give the body to the bass of a battery loop by setting it below 200Hz, try to make the boxes “crack” louder by boosting around 1kHz or raise your treble presence from 4kHz.
If you do not know where to start when equalizing a track or filtering an instrument, our diagram is a good reference point to get an idea of which direction to move.
But it would help if you considered all this only as a guide.
Mixing based on the “norms” is usually a terrible idea. You must listen to what you are doing and trust your ears instead of sticking to the theory. The fundamental frequencies do not have to be the same for each track on each instrument. Make decisions based on what you hear and not based on what you think you should listen to.
Mixing may be the most important reason to study the frequency ranges. As many elements of the mixture struggle to find their place, it is vital to know the location of each part about the others to avoid shocks.
Some songs – the live recording of a group of three or four components, for example – mix almost “by themselves” and do not need more than a few level adjustments to make everything sound good. If you only work with four or five essential elements -battery, bass, guitar, piano, and voices, for example-, join them without worrying too much about crashing, as long as each instrument sounds good, of course. Maybe it’s not the mix of the year, but the different elements will not fight too much.
But if the arrangement is more complicated, the overlapping sounds will create confusing areas in the mix. Unless you are looking for a “sound wall” effect, this situation can be incredibly problematic.
It is essential that you listen to what you are doing and trust your ears instead of sticking to the theory …
Even a simple electronic theme could contain a sequenced pattern of drums, drum loops or percussion, bassline, mattresses, soloists, “stabs,” synthesized riffs, and, above all, voices. With so many different sounds overlapping, the mix will become confused in a heartbeat. That’s why it’s useful to know (more or less) where each sound is housed in the frequency spectrum.
The basic technique to make room is to cut the less essential frequencies of each element. If you have a great riff that fights for a place with the bass line, cut the bass line media from, say, 400Hz up and the bass of the 400Hz riff down – so both will have room.
Basslines and drums are especially problematic since they occupy more or less the same frequencies, and both are vital for the sound of a song. Sidechain compression has become the most used technique to solve this problem in a dance production. It consists of automating the compression of the bass through the sound of the bass drum, giving the latter a momentary amount of extra space in the mix.
If you know which site occupies the fundamental frequencies of each part, you can use that information to preserve the essential elements of both sounds.
On the other hand, if a party struggles to excel, and there are no rival elements, it enhances its fundamental frequencies and gives it more presence.
We never tire of saying that there are no solutions “for all cases” when it comes to mixing a topic, but it is true that a solid knowledge of the frequency spectrum will give you an excellent approach to how to work, and will help you avoid different elements of a theme stick together.