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Musical genre specific average spectral content

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  • Musical genre specific average spectral content

    I was curious about the average spectral power distribution for various types of music, so I hooked the headphone output of my tablet (playing Spotify 320kbs MP3) up to the line input of my laptop and used REW's RTA at 1/48 octave 32k samples with averaging set to Forever. Then I went through some playlists of various genres, playing a few second of music at about 10 roughly equally spaced places through each song. I moved through the playlist until I had accumulated about 800 spectra that were averaged, so probably 15 to 25 pieces of music per genre. With that many spectra averaged, the average spectrum had come close to steady state and wasn't changing much.

    All the spectra were taken at the same volume setting. They are displayed with 1/6 octave smoothing to make them more legible.

    I did check that everything was working properly by looking at Sheffield Labs Uncorrelated Pink Noise 20Hz to 20kHz and it is flat.

    Things to note:

    1) The Dance Mix is my own playlist, with pop and EDM that I like, and it is the only one of the pop music styles that isn't compressed right up to the limit in the 500 to 5000 Hz range. That's probably why I like those songs (on average).

    2) There are slight differences in the amount of bass. Country peaks at 60 Hz before falling. 50 Hz has maximum power across many genres, and only hip hop seems to have significant energy at 30 Hz. Orchestra doesn't have much bass on average, but it is deep (flat down to 20Hz), probably from low frequency, impulsive bass drum hits.

    3) There are huge differences in the amount of compression/crest factor/headroom between pop, jazz, and orchestral.

    4) Piano doesn't have much high frequency content.

    5) It seems that MP3 may have a maximum high frequency content between 10kHz and 20kHz, or everybody is using the same drum and cymbal synth, because all the high frequency pop music has the same limit and slope up high.

    Anyway, it seemed like it might be a useful exercise for thinking about how much power handling is required for various driver and crossover combinations. It is also useful to decide how much bass extension you need for the type of music you listen to.

    Click image for larger version

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    Last edited by msibilia; 08-08-2017, 05:06 PM.

  • #2
    Re: Musical genre specific average spectral content

    Wow! Excellent work. This makes it super-easy to compare the overall "sound" of one genre vs. another. I especially found it interesting that Country and Hip Hop were pretty similar, but with Country having less low bass, and a bit of a peak around 2KHz (no surprises there). Also of note is that the electronic dance music takes it easy on the midrange. Now, where's the rock and metal?
    Isn't it about time we started answering rhetorical questions?

    Paul Carmody's DIY Audio Projects
    Twitter: @undefinition1

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    • #3
      Re: Musical genre specific average spectral content

      I haven't done everything yet, but it is relatively easy to add some more. Maybe tonight.

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      • #4
        Re: Musical genre specific average spectral content

        Individual plots.

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        Last edited by msibilia; 08-08-2017, 05:08 PM.

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        • #5
          Re: Musical genre specific average spectral content

          More individual plots including Classic Rock and Heavy Metal

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          Attached Files
          Last edited by msibilia; 08-08-2017, 05:10 PM.

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          • #6
            Re: Musical genre specific average spectral content

            This is very cool and it really supports what my own ears hear across various genres. Thanks for taking the time to compile the info.
            Bryan K.

            Midwest Audio Club

            Speedster | Sub Attaché | The Wildeman | Sean's NLA Towers | COÜGAR, COUGAR II and COÜGAR JR | Triton | Lithium | J-Boom | Trym MLTL | Docere MLTL

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            • #7
              Re: Musical genre specific average spectral content

              Originally posted by Paul Carmody View Post
              I especially found it interesting that Country and Hip Hop were pretty similar
              Lol I was just saying at work the other day " what are they mixing country and rap now? I'm just gonna call it c-rap "

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              • #8
                Re: Musical genre specific average spectral content

                Originally posted by killa View Post
                Lol I was just saying at work the other day " what are they mixing country and rap now? I'm just gonna call it c-rap "
                Yup, they are. Big Smo and Colt Ford have a pretty big following. Plenty more out there too.
                Bryan K.

                Midwest Audio Club

                Speedster | Sub Attaché | The Wildeman | Sean's NLA Towers | COÜGAR, COUGAR II and COÜGAR JR | Triton | Lithium | J-Boom | Trym MLTL | Docere MLTL

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                • #9
                  Re: Musical genre specific average spectral content

                  Another way to look at this is to consider what instruments are used in various genres.
                  With rock/pop of the 60s and 70s usually you had a 4 string bass so the lowest note
                  was E0 or 41.2 Hz but of course there's no reason why you couldn't also have an 88
                  key grand piano that has A0 as the lowest note for 27.5 Hz. The two most popular
                  acoustic suspension systems of that time the AR-3/3a and the Large Advent had Fc's
                  around 41-42 Hz.
                  28 Hz is I think a good lower limit for most classical music to also cover the grand piano.
                  The vented PSB Stratus Gold is tuned to 28 Hz, there are reasons for these choices.
                  Today we see 5 and 6 string bass guitars becoming more common with, usually, C1 or
                  32.7 Hz as the lowest note.
                  I'm sure most here know that C0, 16.35 Hz had been considered the lower limit for
                  the largest traditional pipe organs.
                  I've always taken these facts into consideration when choosing the extension required
                  for a system.
                  There are of course exceptions there are super pipe organs that I think go an octave
                  lower and pianos such as the Bösendorfer Model 290 Imperial with 97 keys (all extra
                  keys are to extend the bass) that will also do C0 or 16.35 Hz but these are not common.
                  http://en.wikipedia.org/wiki/Imperia...er_%28piano%29
                  Last edited by Pete Basel; 12-31-2014, 12:47 AM.

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                  • #10
                    Re: Musical genre specific average spectral content

                    It was pointed out to me when I was studying audio engineering that those spectra
                    are really all very similar and that this fact was used in the restoration of old recordings
                    such as Enrico Caruso that was covered in a 1975 IEEE paper: "Stockham, T.G. ,Jr.;
                    Cannon, T.M.; Ingebretsen, R.B. (April 1975). "Blind deconvolution through Digital Signal
                    Processing". Proceedings of the IEEE.

                    More on Thomas Stockham:
                    http://en.wikipedia.org/wiki/Thomas_Stockham

                    From that link: "Stockham played a key role in the digital restoration of Enrico Caruso recordings, described in a 1975 IEEE paper.[2] These recordings were the first to be digitally restored by computer, and were released on the 1976 RCA Records album Caruso-A Legendary Performer."

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                    • #11
                      Re: Musical genre specific average spectral content

                      Originally posted by Pete Basel View Post
                      Today we see 5 and 6 string bass guitars becoming more common with, usually, C1 or
                      32.7 Hz as the lowest note.
                      I hate to be the nit-picker, but the lowest note on a 5 or 6 string bass guitar is B0 (30.87 Hz if you like to count frequencies). However, the way they are used by most heavy metal groups now, they tune down from there by third or more.

                      Oh yeah, get your djent on!

                      In your defense, though, Pete, the bottom note of a 5-string upright bass is often C1.
                      Isn't it about time we started answering rhetorical questions?

                      Paul Carmody's DIY Audio Projects
                      Twitter: @undefinition1

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                      • #12
                        Re: Musical genre specific average spectral content

                        I'm not a bass player, I just asked my son who plays lead.
                        Thanks!
                        I am aware of down tuning and there are always exceptions.

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                        • #13
                          Re: Musical genre specific average spectral content

                          This is great info. You really dont need response below 40hz for the majority of music.
                          http://jaysspeakerpage.weebly.com/

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