All about what bass?

With the New Year well upon us, and the Grammy awards this weekend, Alex Wilson reflects on the musical year that’s just passed?

In fact, this is something I find myself doing each year, as for the past seven years I’ve been charting the evolution of popular music recordings. It’s been well documented that recording became louder and more compressed throughout the 1990s, but that trend has more or less stabilised in the last decade [1].

So which other aspects of recorded music have been changing in recent decades and how?

What bass?

By looking at audio features calculated from roughly 10 songs per year since the launch of the Compact Disc in 1982, and plotting the data against year of release, trends in audio production can be observed. A revealing feature to look at is the bass (low-frequency content). By all accounts, 2014 was All About That Bass, so let’s look at the percentage of the total spectral energy below 80 Hz, a spectral measure I’ll call LF Energy. This frequency was chosen because this is a typical crossover frequency for high-end studio subwoofers.

Frequency spectrum

Figure 1. Frequency spectrum of All About That Bass by Meghan Trainor

The figure below uses LF Energy to demonstrate the gradual trend of increasing bass in music.  Some other production trends are discussed in this paper [2].

Increase in LF-ENERGY

Figure 2. Increase in bass (LF Energy) over 33 years

Oh, that bass.

A quick Internet search reveals an insight into how we understood the term “bass” in 2014. The top result is the song, performed by Meghan Trainor, All About That Bass. Under the assumption that the song’s lyrics are literal and refer to preferred frequency balance in pop music, we can test the notion that All About That Bass is truly all about that bass and also has “no treble”.

As shown in Figure 2 above, however, the LF Energy value for Trainor’s song is right on the smoothed line, and so the amount of bass is typical for 2014. Perhaps it is simply the lyrics that draw our attention to the bass instruments in the mix. Also highlighted is Super Bass by Nicki Minaj, where the score is much higher, although this can be somewhat accounted for by the difference in genre, which I’ll come back to later.

Perhaps these results can shed some light on the songs popularity – that the frequency content is not too much or not too little of any particular parameter and sits in the “Goldilocks Zone”, where conditions are perfect for a hit record.

Why bass?

Interestingly, there have been studies on the perception and preference of “exaggerated bass”, which indicated that certain personalities typically preferred higher bass levels [3]. There are also a number of possible reasons for modern productions having more bass.

  • While acoustic instruments would typically be quite large in order to generate low-frequencies (think of large drums or organ pipes), the increased use of electronic instruments and synthesis means this is no longer a restriction.
  • Loudspeaker technology has improved such that we can reproduce these lower frequencies more easily in the home without the need for excessively large loudspeakers.
  • Innumerable songs which refer to the Roland TR-808 drum machine, particularly it’s bass drum sound, as something desirable, since “nothing sounds quite like an 808” [4].

This is supported by a recent study in which the spectral characteristics of pop music recording since 1950 were gathered [5]. This has shown that the amplitude has increased at low frequencies and the frequency at which the bass is loudest has also decreased. This is dependent on genre, with hip-hop showing the highest bass levels and the lowest for jazz, which may rely more on acoustic instruments. Perhaps unsurprisingly, pop music lies in the middle.

Bass content of different genres

Bass content of different genres [5]

Incidentally, “All About That Bass” is nominated in the Record Of The Year and Song Of The Year categories at the 57th Annual Grammy Awards.

How much bass do you like? And why do you think it’s increasing?

Alex Wilson is a PhD student at the Acoustics Research Centre, University of Salford

 REFERENCES:

  1. http://www.soundonsound.com/sos/sep11/articles/loudness.htm
  2. Wilson, A and Fazenda, BM 2014, “Categorisation of distortion profiles in relation to audio quality”, 17th International Conference on Digital Audio Effects (DAFx-14), 1-5 Sept 2014, Erlangen, Germany. http://usir.salford.ac.uk/32490/
  3. McCown et al. “The role of personality and gender in preference for exaggerated bass in music.”Personality and Individual Differences 4 (1997): 543-547.
  4. Beastie Boys, “Hello Nasty”, Compact Disc, 1998.
  5. Pestana et al. “Spectral characteristics of popular commercial recordings 1950-2010”, Audio engineering society 135th convention, New York, 2013

4 responses to “All about what bass?

  1. As a bass player, I like lots of bass. But only in “real” music. Jazz, folk, R’n’B, rock. I also work as a recording musician and am currently working on a solo bass album which will be appearing on the TV and radio in approximately 18 months. And I happen to be a student at Salford also

  2. It will be interesting to relate these dependences with corresponding listener quantity. It seems to me, there will be interesting correlations. And please, add the same for symphonic music too. From my side I have to say, that bass quality strongly depends on room acoustics and it makes often to use equalizers. As concerns bass quantity, there are two main features, which influence on hearing. First is the masking, when too much bass sound damp intelligibility and musical resolution for middle and high frequency ranges. Second – sound “brightness”, which is critical for singer room response. I know examples of such a very “dry” sounds in the halls, which are not popular for concert events.

  3. It should also be noted that it’s much harder to cause hearing damage with low bass, but you can physically feel it. It’s all down to turning rate vs excursion.

    Low frequencies and long transients are “large” sounds, which sound powerful. This is something that people have been looking for in music for quite some time, since the earliest percussion instruments.

    The contemporary parlance describing this phenomenon is “fatness”.

    Tiny little ipod speakers sound thin, fundamentally because they’re small and weak.

    There’s a basic system of aesthetics which is physics-based and intuitively and sensually understood, it’s basically desirable to have a powerful and large sound.

    In the domain of acoustic instruments, there’s always a tradeoff of clarity – high frequency output, vs “fullness” of tone – low frequency output.

    In the case of electronic music, this is still a fundamental limit, almost nobody is encoding masters using 15Hz at the moment, even though most people could hear/feel 15Hz so long as it was really, really loud.

    Figured out the other day we can actually perceive frequencies much lower than audible frequencies, and that this is done using the inner ear. We feel lower frequencies as motion, and our whole body is expected to move like a transducer. We mostly feel these frequencies mechanically transmitted to our bodies. This ultra-low frequency sensual listening is not normally taught as being related to sound, but the organ is the same – the inner ear..

  4. Pingback: Hey! Check out this very interesting blog (Prof. Trevor Cox, University of Salford)! | Hervé's blog

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