Enchanting Instruments 17 - The Low End of Instruments

Over the past half century or so, the importance of low frequencies in music has increased, and instruments have been expanding further into the lower range. These phenomena seem to be driven less by the development of instruments themselves and more by the advancement of playback systems capable of reproducing deep bass, especially speakers.

■ The Lowest Notes of Acoustic Instruments

As for the lowest pitches that can be practically used on instruments, I would say E1 (41 Hz) on the double bass and tuba. If we stretch it, there is A0 (27.5 Hz) on the piano, but I think it’s rare for A0 to actually be used in real musical pieces. There are pipe organs that go even lower, but I think it’s fair to treat them as exceptions. When it comes to low notes that can be easily perceived as pitch by listeners, E1 seems about right to me. Even if we push it a bit further, D1 (37 Hz) feels more than sufficient.

■ Recognizing Pitch Through Overtones

When we perceive the low notes of a bass as pitch, we are not actually recognizing the fundamental tone, but rather the overtones one octave above it or even higher. If I play only the fundamental of the lowest note as a sine wave, you can hear the sound, but I think most people wouldn’t be able to tell what the pitch is. It’s hard to convey this clearly with words alone, so I made a short video. I’m playing a phrase, alternating between a synth bass and a sine wave. If you’re listening through speakers at low volume, when it switches to the sine wave, it may suddenly seem as if the sound has disappeared because it becomes that hard to distinguish. The lowest note in the phrase I’m playing is E1 (41 Hz). Since the human ear becomes less sensitive as frequencies get lower, volume and low frequencies need to be considered together.

■ The Audible Range Starts at 20 Hz

It is said that humans can hear sounds starting from 20 Hz. A 20 Hz tone corresponds to D#0. That is three and a half semitones lower than the piano’s lowest note, A0 (27.5 Hz). Even if I play a 20 Hz sine wave at a reasonable volume, it only sounds like some kind of very low noise. When I listen to the lowest note on the piano, A0 (27.5 Hz), as a sine wave, I can tell that a sound is playing, but it feels lacking in volume, and I can’t really perceive the pitch in the first place. A frequency of 27.5 Hz means there are 27.5 vibrations per second. To distinguish pitch, I would need to accurately tell the difference between, for example, A0 at 27.5 vibrations per second and the semitone above it, A#0 at 29 vibrations per second. With so few vibrations, they simply sound almost the same to the human ear. In order to perceive pitch, a certain amount of higher overtones must be present.

■ Low Frequencies in Percussion

When it comes to percussion instruments that do not have a clear sense of pitch, earth-shaking low frequencies are actually welcome. The role of the orchestral gran cassa (bass drum) is to create impact. Impact requires both loud volume and deep low frequencies. In live performances and other very loud settings, it becomes less about hearing with the ears and more about feeling the vibrations with the body. It’s not the kind of sound that can be easily recreated at home. As for the deep lows of percussion, they are closer to sound effects, so musically speaking, there isn’t a major problem even if some compromises are made. Unless I can produce extremely high volumes, it inevitably feels somewhat lacking—like watching fireworks on television—but that can’t be helped.

■ Bass

In many genres, the instrument responsible for low pitched frequencies is the bass. Since the bass supports the music with its low end, it must be clearly heard as pitch.
There are several instruments that can take on the bass role, but today the electric bass can be considered the main one. Although it is shaped like a guitar, its role inherited that of the double bass. Its range and tuning are essentially the same as the double bass. Naturally, its lowest note was E1. However, by the 1980s, lower notes began to be demanded. I think a major reason for this was the widespread use of synth bass in popular music. With a proper playback system, producing notes lower than E1 on a synth bass is not difficult. Also, since keyboard players were performing these parts, they would use notes below E1 without hesitation, as if playing a piano. When performing such songs on an electric bass, lower notes than E1 are of course required. To achieve notes below E1, the electric bass evolved by adding more strings. Compared to the traditional four-string bass, one or two additional strings were added, leading to what are called multi-string basses, or five-string and six-string basses. The lowest note became B0 (31 Hz). Since professional bassists often need to play exactly what is written on the sheet music, many began using multi-string basses so they could handle whatever came their way.

■ The Development of Multi-String Basses

In reality, when it comes to the development of the electric bass, making it multi-stringed is not as simple as just adding one thicker string. To properly produce lower notes, the body of the instrument itself must be solid enough to handle them. Because bass strings are thick and under strong tension, the load placed on the neck is considerable. Most modern basses, whether multi-string or not, can easily go out of tune simply from their own weight when laid down. In such conditions, low-frequency vibrations cause both the neck and the body to resonate uncontrollably, making it impossible to achieve a focused, solid tone. It cannot really be said that the structure is adequate for the level of string tension involved. There is a claim that attaching a weight to the head improves the sound, but that merely suppresses unwanted neck movement. What is truly necessary is a significant increase in neck strength. I would say that the electric bass is still very much a work in progress.

■ Playback Systems

Consumer audio equipment has become higher-performance, and nowadays even ordinary households can reproduce deep bass. However, I feel that the number of listeners who actually use speakers to listen to music has decreased compared to the past. Large speakers aren’t popular anymore, and few people listen at high volumes, so the lowest notes of the bass are likely not being reproduced properly. What is probably being heard is only the overtones.
In fact, these days, I think more listeners are using headphones to listen to MP3s. With decent headphones, the low-frequency reproduction capability is good enough to produce sounds around 30Hz. But the real thrill of deep bass is feeling the vibrations in your body, so bass heard through headphones still feels lacking.

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