Acoustics !Introduction!In the process of recording music the whole general idea is to record the sound the most accurately getting the most clean and realistic sound possible so that it can be edited at a later date without any problems. Sound is more like a perception however and can be determined by a number of things. In this article i will be talking about the many different ways how sound is examined and analysed. I will be explaining in depth the basics of sound and how elements such as acoustics (psychoacoustics) can have effect on recordings and how you perceive them. We will also be analysing how your ears interpret sound and how this may differ person to person.!!The Basics of Sound!Sound is a very and complex idea and there are many areas that make certain sound like they do, all different elements effect sound but when you get down to the basics even the most contrasting sounds have similarities. Every sound is a wave in some form this is how it travels to your ear through vibrations these waves are often referred to as Sound Pressure Waves. An example of this would be if a singer sings his or her voice will fit molecules into a tightly compressed area which is a distance away from the singer this will cause a higher atmospheric pressure causing the sound to be compressed, This is how the process compression is created. However there is also another process in hearing sound which is called rarefaction which comes about when a vibrating mass, such as when a singer uses their voice or when a guitarist strums their guitar, moves into an area with lower atmospheric pressure. !!Waveforms!A Waveform is the shape of a signal in a physical/graphical representation. What a waveform basically does is show the sound to pressure level so we can visually see for instance when a certain recording peaks and is too loud or when a waveform is quite small in shape and form therefore is a much quieter sound this is extremely useful when working with audio and makes applying effects such as compression much easier as you have a visual representation to work with not just a sound that you can hear. !!!!!!!!!!

!Amplitude !!Amplitude is basically the distance between the centre of a waveform the aptitude determines how loud the signal is. The bigger the distance from the centreline the higher the contrast in air pressure. Having little amplitude in a recording generally means that the waveform is very quiet and will often needed to be rerecorded or severely compressed. It is best to have a fair amount of amplitude when recording audio to get a clear sound, however you don't want to much as you might start to find that certain parts of the audio file distort, this can sometimes be fixed by compressors and limiters but other times the distortion is too much and the audio is classed as un useable. There are two types of aptitudes positive and negative, a positive amplitude is above the centreline whereas the negative amplitude is below the centre line.!!Frequency!Frequency is the rate at which a signal or vibrating mass repeats. The number of repetitions is measured in Herts shown represented as Hz. Often when using plugins such as tremolo or phase you will have a control called frequencies which controls how fast the effect is being applied. The range of human hearing in the younger years is estimated to be 20Hz to 20kHz. Frequencies bellow 20HZ are considered sub audio rates whereas the human hearing range like just mentioned is considered to be the audio rate and anything above that range is ultrasonic. !!!Harmonics !Almost all signals contain a harmonic element in frequencies, the difference between a perfect sine wave and a harmonic wave is that not all of the energy in a harmonic wave is contained whereas a perfect sine wave has all of is energy withheld. Musical instruments almost never produce perfect sine waves but many instruments have harmonic content such as guitars or pianos. Partials are something that helps us locate harmonic content in waves due to their higher played higher than the original pitch of the wave, Partials that do this are often referred to as overtones. Due to harmonics there are many different waveforms produced such as Saw tooth waves, Square waves and triangle waves. there are many more more complex waveforms but these are the more basic ones.!!!

!!Envelope!An envelope is the attack, decay, sustain and release of a sound. The attack of a sound is how long it takes for the sound to become fully effective so for instance if a sound has a fast attack it will produce a quick and loud note whereas a long attack will make a note that slowly increases in volume. Decay is how fast a sound loses its volume. Sustain is the level of volume that the sound is kept at until it is not being played and the release time is how long the sound takes to fade out to silence after not being played. You can find envelopes in a lot of DAW’s and Plugins for instance you can find one in Native instruments massive or even in the EXS24 which comes with logic to help manipulate sounds. You can also find envelopes on plugging such as the auto filter in logic and other effects modules.!!

!!!!!Phase!Phase or phasing is a term giving to a type of technique which is used in a lot of music but can also be applied to waveforms. Ussually when you record something simple like a guitar or a vocal you wont come into contact with any phase but say for instance you were recording a drum kit with 2 overhead microphones but one was much closer than the over, if you record our drums like this they will be out of phase which basically just means the waveforms did not start at the same time and our out of time with each other. Now some people will often use this as a creative effect in there compositions but sometimes it is unwanted in recordings. Phase is measured in degrees and can be fixed but it is fairly difficult, a lot of older mixers have phase buttons just for this matter. !!

How Musical Instruments work!!In music there are many different types of instruments which are stereotypically used in certain genres however these instruments are usually set into categories such as Wind, String and Percussion. These different types of interments all have a contrasting way in which they are worked for instance a wind instrument needs to be blown into for it to work as a percussion instrument needs to be hit to work. All of the instruments in there respected categories have this basic principal of how each of them work.!!!Wind !Wind or Woodwind instruments are one of the musical instrument groups and there are two main sub categories within this group which are flutes and reed reed instruments such as Saxophones. !!The difference between these two sub categories are is that flutes are directly played through the mouth whereas reed interments are played through a mouthpiece which then in turn causes a reed to vibrate inside of the instrument. Reed instruments split into 2 groups which are single or double reeded instruments. The more known and recognisable woodwind instruments are single reeded such as clarinet or a saxophone. However you may know some double reeded instruments such as oboes. To demonstrate the way acoustics affect the way an instrument sounds i have picked one instrument from each section in this case the certain instrument is a Saxophone.!!!

Saxophones are typically used for Jazz songs and other variations of chilled and slower songs. So sound is made in a saxophone by an oscillation of airflow, the reed in a saxophone resonates the air in the instrument which creates pressure and which in turn causes vibrations which makes the sound through the open holes in the saxophone. So to put it more simply the reed operates the air which travels into the saxophone. Relating back to the previous section of the article, the saxophones timbre can change by increasing how loud you are playing as this therefore makes more pressure this in changes the saxophone’s default sine wave and adds more harmonics to the wave and brightens the sound up. !!!

String!String instruments are another group of musical interments which work by a certain string of the instrument being plucked which generates this explains the name given to this category. A couple of examples of instruments that are considered string instruments are violins and guitars. The string section is the largest section of an orchestra and is set into many different sub groups such as violins, violas, cellos and double basses. !!Guitars in some form or another are used almost universally around music, they are used in so much pop, alternative and rock music. But how do guitars work? A guitar works by the vibration of the strings, when you pluck a string it creates vibrations. Each string on a guitar has a different mass and sometimes different lengths. Tuning works by the tension of the string. When strings go out of tune you need to either loosen or tighten the string tension to the appropriate tuning. The main sound from a guitar is surprisingly not from the strings themselves its actually from the body and the bridge. With just the strings you wouldn't hear a guitar half as much with the body and bridge. The purpose of the body of a guitar is to move the vibration of the bridge back into the surrounding air the sound that is made is actually mainly to do with the players finger which is then relayed through the body of the guitar. The Sound-hole of the guitar is the part which contains the lowest frequencies of the guitar due to a lower resonance from inside the body. !!!!!!!!!!!!!!!!!!!!!!

Percussion !Percussion instruments are another group of musical instruments and they are the simplest of the instruments to make them work all you have to do is hit them, in some cases a stick or brush is required. Some examples of percussion are timpani’s and Xylophones. Percussion instruments are mainly used for rhythm purposes. When a drum is hit the sound is amplified due to the empty inside however some percussive instruments like bells resonate when hit. Generally speaking with drums the larger the drum the lower the pitch but drums can be tuned to change the pitch. !!!Drums are used in all genres and are universally known to keep rhythm in songs. They are used in rock, Pop, hip hop you name it theres going to be some form of percussive drums in the song, but how do they work? With drums skin is stretched over the hollow frame of the drum which creates tension and when hit it pushes air into the drum and creating compression. The vibrations of the hit resonate inside the drum and exit the back of the drum creating the sound we hear, bigger drum sizes create bigger sound waves equating in lower pitches. Drums have naturally a fast attack due the resonance inside of the drum.!

!Human Hearing & Psychoacoustics!When making music we rely on our ears for everything they give us the judgement of what decisions to make and what changes to be made but how does our ears affect our work? So first, to understand how our ears affect our work, we have to understand how they work. !!!Your ear has 3 main parts the outer,middle and inner sections. The outer ear contains the ear drum, pinna and eardrum. The Middle ear consists of the ossicles and ear drum and finally the inner ear contains the auditory and cochlea. When you hear a sound sound waves enter your ear canal and make the ear drum vibrate. Then as a cause of this the ossicles moves and the last bone knocks against the cochlea and makes the fluid move inside of the cochlea. The fluid movement then activates the hearing nerve.!!!!How can our Hearing affect our work? !Hearing can affect our work in many ways, our hearing is a very fragile and valuable sense and it can be damaged and if you play music too loud or don't protect your ears well enough this might start to hinder your music production. You might start to lose the hearing of certain frequencies and you might even start to go deaf in one ear meaning that you have almost a mono understanding of music and this would create some problems due to panning. The normal threshold of feeling it happens at the level of 11DB between frequencies of 200Hz and 10kHz. The threshold of pain is 140DB between frequencies of 200Hz and 10kHz. !!Hearing loss is a big issue when it comes to musicians as it can often get hard to protect your ears and keep them at a comfortable hearing level all the time. Gigs are often massively loud due to PA systems and if your standing in front of a speaker that is meant for a whole crowd this may damage your ears if exposed to it for a long time. Temporary or permanent hearing loss may be a risk. !!!!!!

Psychoacoustics!Psychoacoustics relates to the previous topic very well as it is basically the study of how we perceive sound and how our brains interpret music. Although a lot of research has gone into discovering and finding out how the brain does this still a lot is unknown about the subject. We know somethings such as the frequency response of your ear is directly related to the volume of the sound so for instance if you hear a dog barking from far away but also at the same time you drop a pan in from in front of you your going to hear the pan quicker and more clearly as it is louder. Also our ears can actually create there own form of distortion when sound waves are above a certain level. So some sounds at some frequencies may sound different harmonically due to your ears. If you had ear damage to your ear drum like talked about previously and you listened to music at the right frequency range you may be hearing something which is much different to what someone else is hearing due to the frequencies you can hear and also any additional harmonics which your ears have created. !!Beats are two tones which are different in frequency by very small amounts and have the same amplitude this occurrence makes an effect which is called beats. Beats slows down as notes approach a pitch and then stop when the all the pitches match. However this only happens due to the ear’s fault in not being capable of separating closet linked notes. This is also evidence of our ears affecting our work as because of this fault what we hear sounds different to what is actually happening. !!!!!!!!!!!!!!!!!!!!

Ideal Music Studio!So taking all that i’ve talked about into consideration in this article if your planning to make music then you need a great way to listen to it back and be able to analyse your music without blasting your ears and possibly damaging them with concert PA Systems as your main speakers in your studio so here is a guide that adapts the qualities of a specific room. !!So lets say you have a square room like this one here in this picture. There are two door ways in this room now to make this the best it can be you'll have to first start with some real basic soundproofing using things such as foam and bass traps to help you listen to your mix and take away any characteristics that may be harming your mixes such as an echoey room. Now this room doesn't look particularly big so this wont be such a problem but for other spaces this might be so, so the first materials you would need are some sound proofing foam. I picked this room as it generally looks like a good area to have a studio its not like a massively big garage which would have lots and lots of reverb making everything sound bright and echoey instead it is a more natural and controlled environment which should help in making music because of its reasonably sized dimensions. !!Something like these Studiospares Bass traps and absorption tiles should do the trick. The chosen room looks to be around 18ft by 12ft so you would want to get them spread evenly around the room taking into great consideration speaker placement. You may also feel the need to buy some speaker isolation which are pads that can go underneath your monitors which stop and bleed or vibrations into the desk or stands that you could have them placed on. !!!!!!!!!!!!!!!!!!!!!!

!!!!!!Also your going to need a computer and a set of speakers. When choosing a computer there really is no match in my opinion for a mac, considering this is a studio there isn't really any need for portability so an iMac from apple would be the chosen computer that way you can pretty much get and DAW you decide to use whether it be Logic, Cubase or Abelton. For the speaks you want active monitors as passive monitors need power amps and they cost extra money, depending on how much money you have you could spend a a couple thousand on a set of speakers and your music sound exceptional right of thee bat or you can buy a lower price better value for money set of speakers which show you more accurately compared to other audio systems how your mixes sound as after all not everyone can afford 5 grand speakers. A pair of Alesis M1 Active MK2’s should do nicely due to there clean sound they give a much more clean mix and do not boost frequencies like some monitors do, its a nice clean and natural sound given off by these monitors.!!Also you will need an Audio Interface and a microphone to help you record whatever you desire guitars vocals etc. Your going to want these 2 pieces of equipment to be very high quality as they are the essentials for your recordings. To have high quality recordings you're going to want to find an audio interface with high conversion rates meaning the quality of audio recorded will be better in this case a Foucswrite Saffire Pro 40 coupled with a Rode NT1-A will work wonders. A condenser microphone is generally better for recording vocals and acoustic guitar recordings so if you plan to do recordings such as drum or amp recordings you may want to get an dynamic microphone such as the Shure SM57 which is the industry standard for dynamic microphones. Condenser microphones are music more sensitive and pick up sounds much more clearly due to there frequency range and responses and also because of phantom power. !!Now Due to the rooms size i estimate the rooms RT-60 to be around 1.8 seconds but with more sound proofing it would be reduced. Standing waves are a cause of this RT-60 times extra reverb occurs creating other identical waves travelling in opposite directions in the same location. Standing waves are displaced and each wave can have a positive and negative displacement. However due to the standing waves having nodes which there are points of no displacement the antinodes therefore take on maximum displacement from the rest position. !!!!!! !!!!!!!!