When you're at the beach and you listen you can hear lots of sounds: the seagulls, the waves, the wind, maybe kids shouting or passing cars. You may not notice some of these unless you stop and listen closely. When you listen to music, you hear a lot, too. You might hear a guitar, the singer, the bass and other instruments. What you hear and how much of it depends upon a lot of factors, the way it was recorded, the instruments, the style, and how it was written.
Music is usually recorded in recording studios which are constructed in a way to make them very quiet places so that the microphones pick up only the sound you want. They even have padded walls so there's no reverberation (reverb for short) or echo. Once the sound is recorded, the sound engineer may process the sound. This means they alter the sound slightly using software or special equipment. They do this for a variety of reasons: to make it sound louder, or "brighter" (more high frequencies), or sound as if it was played in a concert hall (adding reverb), for example. Most music you hear on the radio has been processed, usually to make it louder so that the loud parts are louder and the soft parts are also loud. This is called compression and it's used in TV as well, especially for commercials. Sometimes, though, music is recorded with very little processing. These recordings tend to be quieter but they also tend to have more dynamic range. That is, if the musician plays louder the sound on the recording is louder, and vice versa. Dynamic range, or dynamics, is how loud or soft the sound can be.
The way the music was written by the composer is also a factor. The composer uses dynamics to control how loud or soft music should be played. Musicians follow the composers instructions and play the notes loud or soft accordingly. For example, if the composer writes pp it means to play that part very softly. If the composer writes ff then the musician plays it louder. And there are other markings the composer can write like crescendo - that means get louder gradually over a fixed length of time - or diminuendo which means gradually get quieter. Some of the really good pop singers understand this concept. If you listen to Elton John's recordings in the 1970's his voice and the instruments played with a lot of sensitivity and there are some really soft parts which make the music really engaging. An example of a classical piece that makes great use of dynamics is Gustav Mahler's Symphony No. 4. Two more examples are Gustav Holst's Venus, the Bringer of Peace or his Mars, the Bringer of War, both from his orchestral suite The Planets. There are really soft parts - so soft it makes us want to turn up the volume but we better not - because here comes a really loud part that will make us want to turn it down again. And there's nothing like hearing a full orchestra - when all the instruments are playing together at a fff - watch out!
The style of music is also interesting to think about in terms of dynamics. Folk music, which is often just voice and acoustic guitar tends to be softer than, say, rock, which is loud by definition. In the 1960's, folk singers like Bob Dylan were using dynamics to draw the listener in and create a more intimate sound. Rock bands, on the other hand, tend to be "in your face" with their screaming guitars coming at you full force. A great example of a loud rock band is the 1980's heavy metal group Quiet Riot - note the ironic name.
Another factor that contributes to how loud or soft music sounds is the instrumentation - some instruments are inherently softer than others. For example, an acoustic guitar tends to be softer than a trumpet. So, we have to consider what instruments we're listening to. Similarly, a composer must consider what instruments he/she is writing for: will it be a flute or a trombone? An electric guitar or an African thumb piano? A bass drum or a kazoo? A favorite example of this is Claude Debussy's solo flute piece Syrinx. It's just one flute and it really draws you in with dynamics and a mysterious melody. Also, how many instruments are there? Five trumpets will generate a lot more sound than one. Sometimes we may only want to hear one instrument - and other times we want a full orchestra. A good example of this principle at work is Maurice Ravel's Bolero. It starts out with just a drum and a single fulte and then, gradually, more and more instruments are added until the full orchestra is playing along - the sound grows from tiny to gigantic over the course of the piece.
Just like there are so many sounds at the beach to hear if we take the time to listen, there's so much music to hear also - loud, soft and in-between. And we can explore these different dynamics through different styles, recordings, instruments and pieces, .. where to begin?