Article by Ludvig Boysen
Why is the bass guitar in metal so often silent and unheard? This is a question which is often answered with audio engineering explanations, but the true cause lies in the composition of the music. Read on to learn the natural and compositional explanation for this phenomenon.
Without adjusting loudness or timbre, multiple instruments can either sound melodically separate and distinct, or they they can merge into one voice, depending entirely on which tones they play. This is one of the reasons for why the bass can seemingly come and go in metal, even though the bassist never stopped playing. To understand this behaviour, one must understand the fundamental aspects of sound: Pitch, loudness, and timbre.
Sound waves are chain vibrations through a medium, such as air. That materials can vibrate is a fundamental part of nature, like magnetism, and like objects moving due to kinetic energy. Examining it in detail is beyond the scope of this article, but some basic physical phenomena can help explain the silence of the bass in metal.
Pitch is how high we perceive a sound to be. The rumbling of earthquakes is a low pitched sound. The singing of small birds is a high pitched sound. The physical factor which determines pitch is frequency. When an object vibrates, like a metal string attached to an instrument repeatedly does after being plucked, it causes the air around it to vibrate, which in turn vibrates the air next to it in a chain reaction. This is perceived as sound when the vibration reaches our ears. The more times per second that the string swings all of the way from one side to the other and back again, the higher the frequency is, and the higher the perceived pitch. In other words, the pitch is higher if the time between each successive wave of vibration arriving is shorter.
Loudness is how strong we perceive a sound to be. Whispering is a quiet sound. Shouting is a loud sound. Amplitude is the main physical factor which correlates with perceived loudness (although there are more factors than one). The farther out an object oscillates from its equilibrium point, the higher the amplitude is. Higher amplitude oscillations cause the eardrum to be displaced farther, and the sound is perceived as louder.
Timbre is the character of a sound besides its loudness and pitch. When a guitar and a banjo play the same pitch with the same loudness, timbre is the only difference between the two instruments. Timbre is determined by the nature of an object’s overtones. Overtones are partial oscillation. When a string oscillates, it is not only the entire string that moves, but also subsections of it. These smaller sections of the string oscillate independently at the same time, with higher frequencies than the entire string, producing higher pitches.
We don’t hear these pitches as separate voices. Instead, we only perceive the pitch of the entire string’s vibration, which is called the fundamental frequency. The partial vibrations only colour the sound of that pitch. Different materials behave differently, and depending on the nature of the vibrating object, different partials will be more or less emphasized, being louder or quieter. This is what gives each object its own timbre.
In some sounds, entire partials can be utterly absent, like in the synthetic timbre of the sine wave, a sound which is produced by no more than one single fundamental vibration, completely lacking overtones. In other sounds, there are so many subsections vibrating that we can’t perceive a fundamental pitch at all. It is drowned out. Many drums are like this. We can differentiate between higher pitched and lower pitched drums of this kind, but we can’t determine which pitches they play, unlike with melodic instruments. Even if a drum played the same fundamental pitch as a guitar, it would be very hard to hear that it did.
There are some overtones which are very common, and very pronounced. Almost every musical timbre has these overtones. The first, strongest overtone, is a partial vibration with a frequency twice as high as that of the fundamental. Its relationship to the fundamental is the ratio of 2:1. The second overtone has a higher frequency at a ratio of 3:2 compared to the first overtone.
In metal, harmonic relationships of simple ratios, such as 3:2 and 2:1, are often favoured, because they sound powerful and consonant. However, this has the effect of blending two voices into one, because when the fundamentals have frequencies that constitute simple ratios, just like the strongest overtones, our minds hear one instrument as an overtone of the other, instead of as a separate voice.
It is possible to make use of these simple ratios while maintaining melodic independence, but it requires interspersing simple ratios that are like the strong overtones, with more complex ones that are like the weak overtones. Since no natural timbre could change like this from note to note, our minds perceive independent melodies. It is only when the two melodies move in parallel, maintaining a simple ratio between each other, that they blend into one voice. With only one octave to work with when the guitar is playing its lower tones, there’s not much room for strong independent melodies within this constraint, so parallelism is often chosen, and that’s the reason for the silence of the bass.
9 thoughts on “The Silence of the Bass”
Being impressed by a busy rhythm section is for Africans. Whites build a foundation and then build on that foundation to achieve something greater. very analogous to black and white societies.
An interesting notion. Does it relate to this article, and if so how?
Do you consider bass to be a rhythmic instrument? I consider it a melodic one.
Exactly. It can be used in whatever way, also according to racial inclinations. It can build counterpoint. Playing tremolo on guitar is actually one such example, when the use of the instrument has been adapted to the user’s needs, probably to mimic majesty of (modern) classical music: https://www.youtube.com/watch?v=vlO-VCdZiRA
Do you consider the bass guitar to be a rhythmic instrument? I see it as melodic.
Rhythm is still very important in all types of music. Goodness heavens, you are ignorant.
In classical extreme metal, producers let a lot of guitars in the 80 Hz spectrum and below. That let very few space for the bass and kick drum. Good producers manage to give a special Spectrum for that two elements but, human ear is more focused on the mid range and upper midrange. That’s why we ear better the guitars. In modern production, people use some high pass filter around 70hz 100 Hz or even higher to have tighter guitars and more room for the bass and the kick. Somtimes they boost around 1kHz to add presence to the guitars. Unfortunately that gives the djent sound, which is very gerenic. I prefer the « mistakes » of the 90’s style swedeath with a undefined rumble in the sub-bass.
There’s an audio engineering part to the explanation, but even with the engineering being what it is, the bass would be clear if the composition was different, on albums like Left Hand Path. As it is, its level of definition varies on the album.
You’re talking about differentiating timbres, and that is more of an engineering question. I’m talking about making melodies independent, given any timbre, even the same one. What I’m saying applies to ‘poorly’ mixed guitar and bass guitar, to one keyboard, to two guitars, etc.
Indeed. This is why when they play in parallel, it is the guitar that dominates, rather than the bass. The way to get the opposite, or a more even blending together of the two, that is an audio engineering issue, and on some albums, the balance is more bass favoured than on others.
i find that a lot of my favourite black metal bands use pretty prominent bass lines, i.e. Mayhem, Burzum, Darkthrone, Ildjarn.
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