The frequencies an ear can hear are limited to a specific range of frequencies. The audible frequency range for humans is typically given as being between about 20 Hz and 20,000 Hz (20 kHz), though the high frequency limit usually reduces with age. Other species have different hearing ranges. For example, some dog breeds can perceive vibrations up to 60,000 Hz.
In many media, such as air, the speed of sound is approximately independent of frequency, so the wavelength of the sound waves (distance between repetitions) is approximately inversely proportional to frequency.
Now, all the above sounds very complicated and I have linked certain words (highlighted in orange) if you need to know more, but in very simple terms a single sound, for example a single bass drum beat, will contain certain frequencies as well as amounts (volume). It will also depend on the size of the drum as well as it's shape and the sound may well behave differently but the mechanics of the drum sound will be constant enough for frequency analysis. So a four piece band consisting of drums, bass guitar, lead guitar and vocals will all sound different, therefore if there is too much bass drum the Sound Engineer hears that, often with the help of a Spectrum analyzer and makes the required adjustments on his mixing desk, which could be volume, EQ or even both.
REMEMBER - ANY recorded sound can be manipulated or edited. All recorded sound should not be trusted unless you have recorded it yourself and know it's genuine.
SOUND SAMPLES - Understanding what has been recorded and the frequency spectrum.
The art of recording any sound has it's problems let alone sitting in an empty room recording what you think is silence to find out later you have recorded a voice or sound. Certain sounds use certain frequencies. So let us now look at some samples of sound that have been recorded and view it in the form of a movie but with a spectrum analyser activated.
This first sample is of three different breeds of dogs barking but not at the same time. The dogs have been recorded and the sound sample placed into software called DAW (Digital Audio Workstation). Software types and costs, some are free, will be covered later in a different chapter.
The screen shot below shows the track recorded (arrow pointed upwards) and the frequency analyser (arrow pointed right) Note explanation given. As the recorded sound is played the spectrum analyser activates and shows the frequency affected.
You have heard and seen (using a spectrum analyser) two different sound sources in the movie's above. Clearly each sound source uses different frequencies. There maybe some over lap but in general terms different sound objects can/will differ in exact frequency.
Before we look at other sound sources let us take a look at 'White Noise' - a term you would of heard of. Before we do that let me explain what 'White Light' is, this will help you understand the make-up of 'White Noise'.
FURTHER STUDY: I have placed four additional sound file movies below to give you further examples of sound analyses. These are the issues your going to face with your own recordings. As you read through each Chapter the subject of sound will become clearer.
SOUND SPECTRUM EXAMPLE - ACOUSTIC GUITAR