The description of a genre is a collection of patterns. Songs that share patterns can be grouped in a genre that describes those patterns. You can find these patterns in any music dynamic: rhythm, speed, progression, key, instrumentation, whatever.
You determine the genre of a song by identifying these patterns, and associating them with the description of a genre.
For example, let's create two genres: fast music and slow music. Any music below 120 bpms (beats per minute) is slow music, anything faster belongs to the fast music genre. Listen to X song, count how many beats you heard in a minute, and group it the genre it belongs to. Genres work exactly like this, but with many more associated characteristics.
For another example, let's define two genres. I'll just use over-simplified definitions to make the point clearer.
Techno: Little harmonic and melodic movement (if at all). Emphasis in rhythm and percussive instruments. There is small variation through the song (no climax, no distinctive sections, for example).
Trance: Both melodic and harmonic movement. Emphasis on bass, and time-based effects like reverb and delay. Sometimes features string-ensemble-like synthesizers (known as pads). There is variation through the song (it has well-defined intro, break-down, climax, and other sections).
Both Techno and Trance: Loop-based electronic music, based on samplers and synthesizers, carved for the dance floor.
Listen to this:
There is no harmonic movement, with some melodic movement, which repeats through the song. The movement is injected through the timbre of the melody part, and the percussion part. There is little variation through the song, with no distinctive sections. This song is a good fit for our simplified techno definition.
Now listen to this:
There is harmonic and melodic movement. It has distinctive sections (intro, break down and start of build up at around 3:50, climax at around 5:30, outro). A lot of reverb and delay is being used. This is a good fit for our Trance genre, even if it doesn't feature pads.
Sometimes it's hard to draw an objective link and define a genre objectively, so the genre subject is often a source of debate.
Since musicians can be very creative, not all songs have a specific and defined genre. Some are a combination of many, others present a new pattern with no associated genre at all (for example, in our fast-slow music example, what do we do with songs that have no evident tempo, or songs with variable speed, or a song that can be described at more than one speed like 80 and 160 bpms?). In contrast, there are songs that share well-defined patterns (by tradition, convention, influence, whatever) and are easier to catalog.
- Visit http://everynoise.com/engenremap.html
- Scroll to the right and you'll find a little search box at the top of the screen, so now type in an artist e.g. Queen
- All genres associated with all songs on Spotify at the time the genre list was produced will appear below the search box!
Have fun navigating the website, it's one of my favourites by far.
I will be simple... year does not matter much... it's more about the types of samples you use and the type of instruments and sounds you use. The only problem with your sample tracks (not mocking you as you did great explaining it) above is that you picked a Detroit techno track (WHICH IS FINE); however, there are many sub-genres the fall under techno... location of the creation also influences the genre choice.
So, to recap :)
Genre is based on year, location and most importantly it's strongly based on the sounds you use to create the track (e.g, type of snare, cymbals, shakers, kicks, hi hats etc...) However, This is not always as clear. Sometimes one genre is almost exactly the same as one another.
None of the previous answers actually addresses the question of determining the genre of a particular song. Here's one way to do that:
- Add your song to a playlist in Spotify
- Go to that playlist, click the '...' button -> Share -> Copy Spotify URI
- Go to http://organizeyourmusic.playlistmachinery.com
- Choose "A specific playlist" form the dropdown
- Paste the Spotify URI of your playlist
Organize Your Music will analyze the playlist and show the genre of each song:
OYM is open source. How exactly is works is that it fetches the genres of some album the song is in (if any - I have yet to seen the Spotify API return any genres for any album), then those of the artist, and returns the first genre from that list. Spotify doesn't supply per-track genre information, so this is the best that can be done using the Spotify API. Note also that Spotify considers "edm" a genre, when it's actually an umbrella term for electronic music in general (contemporary mainstream club stuff).
You can also use it to analyze your entire music collection on Spotify. Interesting to see which genres are most represented.
One easy and direct way of finding the genre of a song is to search for it at Discogs. The most specific genre will be listed under "Style":
Discogs is crowsdourced (like AllMusic), so the genre is the opinion of the person who contributed the entry.
Note that some songs aren't available (e.g. Nora En Pure - Don't Look Back), or they're part of albums and you can't find the individual track genre (Coldplay - Arm of One).