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Thu 15 November 2007
11:21am
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As we saw in 
part 1, sound is made up of waves of compressions and rarefactions in the air molecules around us. In this post we are going to look at frequency and wavelength and how they relate to these compressions and rarefactions and how they relate to each other. I think it is important to understand these when creating music with a computer. Understanding frequencies can really help with your mixdowns and EQing.
Wavelength
In a sound we get compressions and rarefactions in the air molecules, when we look at these in a waveform editor we see a wave. In the picture below we can see a waveform of a sine wave. Wavelength is very easy to understand as it is the distance between any two points at the exact same point in the cycle of the wave. The arrows in the image below show the wavelength and points in which you can measure it.
These points in effect relate to the the distance (the wavelength) between these compressions and rarefactions in the air molecules of the sound wave travelling through the air.
Relating Wavelength to Frequency
Human ears can hear a range of different frequencies which can be measured in Hertz (Hz) and a human has a hearing range from around 20 Hz to around 20,000 Hz (or 20kHz). This would be someone with very good hearing and these values vary from person to person and they also vary with age.
If a sound has a frequency of 1 Hertz it means that there was one cycle (wavelength) in one second. Low sounds are lower in the number of wavelength, so 60Hz would be a bass sound. High sounds such as those at say at 10kHz will sound high like a whistle. The human voice typically is between 100Hz and 3kHz.
Our ears are not sensitive to each frequency in equal measures. We are much less sensitive to the sounds at the extremes of our hearing. The range where humans excel at hearing ability is approximately 100Hz to 3kHz. This range is funnily enough where the main frequencies of the normal human voice are.
Article written by
Edward Cufaude for Rhythm Creation.
part 1, sound is made up of waves of compressions and rarefactions in the air molecules around us. In this post we are going to look at frequency and wavelength and how they relate to these compressions and rarefactions and how they relate to each other. I think it is important to understand these when creating music with a computer. Understanding frequencies can really help with your mixdowns and EQing.Wavelength
In a sound we get compressions and rarefactions in the air molecules, when we look at these in a waveform editor we see a wave. In the picture below we can see a waveform of a sine wave. Wavelength is very easy to understand as it is the distance between any two points at the exact same point in the cycle of the wave. The arrows in the image below show the wavelength and points in which you can measure it.
These points in effect relate to the the distance (the wavelength) between these compressions and rarefactions in the air molecules of the sound wave travelling through the air.
Relating Wavelength to Frequency
Human ears can hear a range of different frequencies which can be measured in Hertz (Hz) and a human has a hearing range from around 20 Hz to around 20,000 Hz (or 20kHz). This would be someone with very good hearing and these values vary from person to person and they also vary with age.
If a sound has a frequency of 1 Hertz it means that there was one cycle (wavelength) in one second. Low sounds are lower in the number of wavelength, so 60Hz would be a bass sound. High sounds such as those at say at 10kHz will sound high like a whistle. The human voice typically is between 100Hz and 3kHz.
Our ears are not sensitive to each frequency in equal measures. We are much less sensitive to the sounds at the extremes of our hearing. The range where humans excel at hearing ability is approximately 100Hz to 3kHz. This range is funnily enough where the main frequencies of the normal human voice are.
Article written by
Edward Cufaude for Rhythm Creation.
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Wed 14 November 2007
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03:51pm
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Sound science is good to know about when recording, mixing and composing using editing software, samplers and synthesizers and today we are going back to basics to learn what sound really is.
Every sound has a source and at the source you will find that the sound is created because something has vibrated back and forth. This vibration at the sound source may not even be visible but as our source vibrates it passes this vibration onto the air around it (or whatever other matter is around it for example water).
These compressions and rarefactions make up the sound wave. The best way to visualize these compressions and rarefaction is to get a slinky (Yes one of those things that "walks" down the stairs) and two people hold it at each end and spread apart. One person then compresses the end by pushing it towards the other person and you will see that sections will compress and decompress and the "message" will get transferred from one end to the other. The same way a sound moves through the air.
Sound travels in all directions from our sound source, just like when you drop a stone in water and the ripple effect goes out in all directions. Eventually it will then come to our ears. Our outer section of our ear (the bit you can see and pull) collects the sound up and helps to direct it down the ear canal. Sound travels down the ear canal and hits the ear drum (the tympanic membrane).
Just like our sound source passes on the vibration to air, air passes it’s vibration onto our ear drum as our ear drum copies the compressions and rarefactions. Our ear drums then pass this vibration message on through some tiny bones, the cochlea, hairs and some nerves to our brains, where we process the signal.
A good understanding of sound science can really help Music Creation and here at Rhythm Creation we will be bringing more articles about sound science such as what is frequency and reverberation amongst other things.
Article written byEdward Cufaude for Rhythm Creation.
Every sound has a source and at the source you will find that the sound is created because something has vibrated back and forth. This vibration at the sound source may not even be visible but as our source vibrates it passes this vibration onto the air around it (or whatever other matter is around it for example water).
- As our sound source vibrates forward it bumps into air molecules and pushes them closer to other air molecules, we end up getting a section of air molecules crowded closer together. This is called compression and if we were to see this on a waveform editor it is when the wave goes above the centre line (a peak).
- As our sound source vibrates backwards it pull the air molecules apart and increases the distance between our air molecules making them less crowded. These are called rarefactions and these are when the waveform goes below the centre line in an editor (a trough).
These compressions and rarefactions make up the sound wave. The best way to visualize these compressions and rarefaction is to get a slinky (Yes one of those things that "walks" down the stairs) and two people hold it at each end and spread apart. One person then compresses the end by pushing it towards the other person and you will see that sections will compress and decompress and the "message" will get transferred from one end to the other. The same way a sound moves through the air.Sound travels in all directions from our sound source, just like when you drop a stone in water and the ripple effect goes out in all directions. Eventually it will then come to our ears. Our outer section of our ear (the bit you can see and pull) collects the sound up and helps to direct it down the ear canal. Sound travels down the ear canal and hits the ear drum (the tympanic membrane).
Just like our sound source passes on the vibration to air, air passes it’s vibration onto our ear drum as our ear drum copies the compressions and rarefactions. Our ear drums then pass this vibration message on through some tiny bones, the cochlea, hairs and some nerves to our brains, where we process the signal.
A good understanding of sound science can really help Music Creation and here at Rhythm Creation we will be bringing more articles about sound science such as what is frequency and reverberation amongst other things.
Article written by
Edward Cufaude for Rhythm Creation.-
Tue 13 November 2007
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04:42pm
- View Comments
ADSR. You may have seen these letters on synthesizers and samplers. This tutorial is a quick guide to what ADSR is and how you can use this section on your hardware or software to shape your sounds. It is an extremely powerful section, and should be one of the first things you learn when learning how to program synthesizers or samplers.
ADSR stands for Attack, Decay, Sustain and Release and does a very important job of shaping our sound from as soon as the note is pressed until you can no longer hear it.
A is for Attack
Basically this sets the amount of time after a note is pressed that it takes the sound to reach the full volume level, attack starts as soon as a sound plays when a note is pressed. Setting this low will mean the full volume will be reached very quickly, a snare drum has a very quick attack as it reaches full volume straight away. Setting this high will mean the sound fades in slower like for example a cello would. As you can see the attack is a very powerful in shaping the start of your sound.
D is for Decay
As soon as our sound has reached its full volume after the attack, it moves on to the decay. Decay basically sets the amount of time it takes for the volume to reduce to the level of the sustain after the attack section of the sound. If we set this to a low setting (less decay) the sound will minimize in volume slower to the level of the sustain (next section). If we set this high your sound will drop almost instantly to the level of the sustain.
S is for Sustain
Our sound attacks and then decays to the level of volume set in the sustain section. If you set this to nothing, your sound will not have any sustain and so won’t carry on further than the decay section (even though the note is being pressed). If you set this higher your sound will maintain the volume for the amount of time you pressed down a note. A snare drum has no sustain, where as something like a trumpet is being sustained for the amount of time that it is actually being blown into (note being pressed).
R is for Release
As soon as we release our note the release section takes over (provided our sound didn’t die away completely because of a high decay setting) . The release is by how long you can still hear a sound after the note finishes being pressed, if this is set to a very low setting our sound will finish very quickly and no audio will be heard. If we set this to a high level our sound will continue to sound for much longer even though we are no longer pressing down on the note. A Gong has a long release (We are no longer hitting the gong, but it’s still vibrating creating sound)
Quick Recap
Tutorial Written byEdward Cufaude for Rhythm Creation.
ADSR stands for Attack, Decay, Sustain and Release and does a very important job of shaping our sound from as soon as the note is pressed until you can no longer hear it.
A is for Attack
Basically this sets the amount of time after a note is pressed that it takes the sound to reach the full volume level, attack starts as soon as a sound plays when a note is pressed. Setting this low will mean the full volume will be reached very quickly, a snare drum has a very quick attack as it reaches full volume straight away. Setting this high will mean the sound fades in slower like for example a cello would. As you can see the attack is a very powerful in shaping the start of your sound.
D is for Decay
As soon as our sound has reached its full volume after the attack, it moves on to the decay. Decay basically sets the amount of time it takes for the volume to reduce to the level of the sustain after the attack section of the sound. If we set this to a low setting (less decay) the sound will minimize in volume slower to the level of the sustain (next section). If we set this high your sound will drop almost instantly to the level of the sustain.
S is for Sustain
Our sound attacks and then decays to the level of volume set in the sustain section. If you set this to nothing, your sound will not have any sustain and so won’t carry on further than the decay section (even though the note is being pressed). If you set this higher your sound will maintain the volume for the amount of time you pressed down a note. A snare drum has no sustain, where as something like a trumpet is being sustained for the amount of time that it is actually being blown into (note being pressed).R is for Release
As soon as we release our note the release section takes over (provided our sound didn’t die away completely because of a high decay setting) . The release is by how long you can still hear a sound after the note finishes being pressed, if this is set to a very low setting our sound will finish very quickly and no audio will be heard. If we set this to a high level our sound will continue to sound for much longer even though we are no longer pressing down on the note. A Gong has a long release (We are no longer hitting the gong, but it’s still vibrating creating sound)
Quick Recap
- Attack - The amount of time after the note is pressed it takes for the sound to reach full volume.
- Decay - The amount of time it takes for the sound to decay to the volume of the sustain section.
- Sustain - The amount of time our sound stays sounding whilst the note is being pressed.
- Release - The amount of time we can still hear the sound after the note has been released.
Tutorial Written by
Edward Cufaude for Rhythm Creation.
