Development of the Overall Project

Throughout this project there were many points in which the concept changed and deviated until it arrived at the point of a strong research investigation. This section of the portfolio will underpin the changes that happened throughout this project and problems that were encountered before the researcher arrived at the final project Aim.

The first concepts for this project were not about music reproduction but about how to reproduce a live event. The Live Music Industry is an ever-growing sector in the Music Industry:

“In 2008, consumer spending on live music is reported by several sources to overtake spending on recorded music in the UK”

Frith Simon. 2010.

Analysing Live Music in the UK: Findings One Year into a Three-Year Research Project

Edinburgh, UK

It was this statement that inspired an idea that a music event could be reproduced over and over again by the use of surround sound. The project was based around comparing different surround audio production techniques to find out which would produce the best reproduction of the original event. However, it became clear that this idea was unrealistic given the time frame when evaluating the process of gathering recordings from local live events. There were two versions of each extract from the events utilizing different techniques, one known as “Upmixing”, which is where the centre and rear channels of the 5.1 system are created from the original stereo mix with added delay and phase differences. The other technique was recording the event utilizing 5.1 microphone arrays. Two events were recorded one DJ set in a local venue called Dukes Corner and the other a live performance from acoustic artist Rhauri Campbell.

It was evident that the difference between the production techniques was minimal and other reasons are also covered in the following points:

1. The lack of a large audience made it difficult to create recordings that contained a good enough amount of audible crowd noise. This is one of the main aspects of live music recordings that create a sense of listener immersion; so that the listener feels like they are in the crowd of the original event. Lack of crowd equals lack of sound sources to create better sense of directionality and localization.

2. Compromised microphone placement in the Dukes Corner event had undesired effects on the mix. The microphone array was supposed to be placed as close to the crowd as possible (ideally in the middle), however this was not possible due to the lack of outputs on the venues mixing desk to record line outs from the DJ's mixing decks. In light of this, a decision was made to place the array behind the DJ to create the mix from his perspective. However, due to the lack of people at the event the array was no longer capturing enough crowd ambience but instead only captured room ambience and reverberation.

3. Time scale at this point became a huge factor and in order to gain mixes that would be suitable for testing, a new event would have to be organized and promoted well enough that a large crowd would attend. Neither knowledge nor the resources were available to do this successfully within the time frame.

4. The whole project concept was weak, as most live event recordings are not completely audio based but most of the time include visuals for DVD and Television broadcast purposes. A large part of reproducing live events is obviously in the recording of the audio, however visuals also play a huge part in event reproduction.

New Concept:

It is for those reasons that the project concept was changed to a more stronger/solid idea. Throughout the duration of semester one while researching surround sound there were many references to surround sounds uses in the Film and Games Industry, however not much in the way of its uses in the Music Industry:

"In modern times we see it (Surround sound) firmly established in applications accompanying a picture for movies and television, but in other areas such as purely for music reproduction broad success has been more elusive. However using history as a guide to the future there may well be a broader place for surround music in coming years"

Holman Tomlinson, 2008, 

Surround Sound - Up and Running, Second Edition

Oxford, UK

It is for this reason that the project concept was changed: to focus on how and why 5.1 surround sound has become a standard format for the Film Industry and is becoming more popular in the Games Industry, with different surround systems such as headphones dedicated for purely gaming purposes. However, stereo is still the standard format for the music industry and not much in the way of surround audio is available purely for music reproduction. Thus, the final project concept was created in order to test the listener’s preference and find out the main differences between stereo and 5.1 surround sound speaker systems and their uses in music reproduction.

Aim:

An investigation into the listener preference between stereo and 5.1 surround sound playback formats. This study is purely investigating the listener preference between the two playback formats' uses in music reproduction.

Objectives:

1. Define the main differences between stereo and 5.1 surround music production.

2. Produce 5.1 Surround Sound mixes of two pieces of music from contrasting genres.

3. Test the Listener Preference between the Surround Sound mix and the original Stereo mix of the two contrasting pieces of music.

4. Find out how people currently purchase, access and playback their music.

Evaluating Achievement of Developing Personal Skills

In a previous post i described three aims in which i have set myself for the duration of the project in order to develop my personal skills as a sound engineer producing 5.1 music material:

1. Broaden knowledge of the mixing and mastering stages of 5.1 music production. 
2. Learn how to exploit the 5.1 mediums attributes to their full potential in remixing source material.
3. Develop investigative skills into cultural aspects relating to music reproduction.

I have achieved my first aim by providing summaries of the key difference between stereo and 5.1 music production preciously in my blog and in the main body of my dissertation. Not only this but not just in terms of studio music production but also live music production in the first few months of the development of my project concept. 

The second of my aims was achieved by applying the knowledge i had gained in researching the main differences in how each reproduction system is used in the separate stages of music production: How 5.1 music differs in the listening experience compared to stereo and the way in which studio effects are exploited through the reproduction system. I applied this knowledge practically in producing 5.1 mixes for two songs from contrasting genres. The reason for using contrasting genres was to again broaden my skills in mixing different instrumentation in 5.1, however it also served the purposes of the listening test as different genres are mixed differently and create different listening experiences.  

In trying to develop my investigative skills in terms of cultural aspects i produced a questionnaire to try and find out how people currently access and playback their music. This was in order to gain and understanding of what kind of impact does the way people access there music have on the reproduction system they use. In order to develop my skills in understanding the cultural side of things i also carried out research on different peoples states of involvement while listening or watching media. For instance a person with little knowledge 5.1 music and the way that it's produced will have an emotional response to the audio rather than someone with a lot of knowledge of the subject they will have a more analytical response according to (Media psychology  "is not yet there"- Introducing theories on the media entertainment to the presence debate by Christof Klimmt, Presence. Vol. 12 No. 4, August 2003, pg. 346-359).

Questionnaire Results

This questionnaire was created to achieve objective four of this project. Sixty-nine participants took part from the ages of 18-60 and from a variety of backgrounds such as audio and games development students, restaurant staff, music retailers, accountants and film industry professionals. The participants were accessed through Abertay University and online questionnaire tool Surveymonkey (2013), which allows surveys to be posted on social networking websites such as Facebook (2013).

The results show some interesting figures:

Figure - Question 1

Figure - Question 2

Figure - Question 6

The Figure for question one shows that only a third of the participants own a 5.1 surround sound system. This is interesting to see seen as this system has been around in the mass market for almost two decades and yet such a high percentage of the participants do not yet own one.

The following two questions were for the two thirds of the participants that do not own a 5.1 surround system. The aim of these questions was to find out if they would consider purchasing one and if not the reasons for this. The Figure for question two shows that just under 60% would consider buying a 5.1 system. The other 41.3% said that they would not consider purchase the system, this is a relatively high number and upon further investigation into the participants comments on question three and results for question six the reasons for this are clear. 

Participants comments on question three stated that they thought 5.1 systems were "too expensive" and even that "stereo is good enough for listening to music". The figure for question six again confirms that a high percentage of the participants still prefer stereo for music reproduction. 40.58% said that even given the choice they would still prefer to listen to their music in stereo format. 

Figure - Question 4

Figure - Question 5(A)

Figure - Question 5(B)

Questions four and five look further into the third of the participants that own a 5.1 system and what type of media they use their system for. It is shown is the figure for question four that the majority of the subjects that own a 5.1 system use it for films, games and television, however, almost 20% do use it for listening to music. These results confirm that the majority of surround sound owners do use their system for media with a visual basis. 

Question five's aim was to find out wether the participants knew if they had music in a surround sound format. This question has been split in to two different figures, one for only subjects that own a 5.1 system 5(A) and the other for all subjects 5(B). 

Question 5(A) shows that a high percentage of the subjects that own a 5.1 system either do not own or do not know if they own any music in a 5.1 format. 34.78% said that they don't own any music in 5.1 surround and the same percentage said that they do not know, this is almost 70% of the subjects that own a 5.1 system. It is very interesting that such a high percentage of system owners do not know if they own music in a surround format and is leading towards the notion that this is a gap in the consumer's knowledge about the difference between stereo and surround file formats. 

Looking at the figure for question 5(B) for all participants, it further confirms that there is a gap in the consumer's knowledge about music file formats. 56.52% of all the subjects said that they did not know if they owned music in a surround sound format. This gap in the consumer's knowledge could possibly be one of the reasons for the lack of the 5.1 systems use for purely music reproduction. 

Figure - Question 7

Questions seven and eight's aim was to find out how the subjects currently purchase/access and playback their music. The majority of the comments on question eight stated that they use headphones, computer speakers and car speakers for playing back their music. Headphones are not an ideal listening environment for stereo listening as they direct sound straight into the ear canal, this diminishes the cues for direction and localisation in human hearing (see glossary of terms human hearing section). 

Questions seven's figure shows that the majority of the subjects download or stream their music files. This means that they are most likely to be small compressed audio files such as MP3, which is a "lossy" format, this means that when the file is converted to an MP3 some of the music's detail is lost unlike Wave files used on CD's. Surround sound music files are likely to be very large compared to stereo MP3 files, this makes the probability of fast downloading or streaming less likely. 

Exposition 7

In order to minimise the difference in quality between the surround headphones and the stereo headphone i have made sure they are both of equal build quality and price range.

Other information that will be provided in my exposition will include some of the overall results from my tests and also research images.

Allan blumleins drawings of a stereo system in 1931

5.1 surround system

Also will provide an explanation how the surround headphones only utilises one cue for direction in the human hearing HRTF and that a full 5.1 system creates better localisation. However, surround headphones are used in the exhibition because headphones a popular playback medium that people will be familiar with. 

Glossary of Terms

Effects

Automation: This is the effect of creating events that will happen automatically when you play back the audio. For instance, automation can be used on the volume of a sound while it is playing so it automatically gets louder or softer. It can also be used in combination with panning to create the effect of sound sources moving around the speaker array and any other effects.

Compression: An effect used to reduce the dynamic range of a sound

Delay: An effect which stores a sound and then replays it over a period of time.

Equalisation: This is an effect used to alter the frequency range of a sound. It allows you to either cut or boost a set of frequencies, for example, if a sound contains too much "bass" or lower frequencies then they can be reduced using equalisation. 

Limiting: Is an extreme form of compression which limits all signals above the threshold to the same gain, rather than smoothly reducing it. 

Optimum Gain Signal: This is not an effect but rather how to record sounds at an optimum level. If a gain structure is too low then noise begins to be introduced to the sound. If a gain signal is too high then the sound will begin to distort. An optimum gain signal for recording audio is around 0dB, this is high enough to not introduce noise and allows enough headroom so the sound will not distort. 

Panning: Is the spread of a sound signal into a multichannel or stereo sound field. In other words panning allows you to place sounds around the speaker array, whether it be directly coming from one speaker or between speakers creating a phantom image. 

Reverb: is an effect which simulates a component of sound that consists of the reflections of the sound bouncing of the walls or objects in a room. In other words it is a room simulator. The reverberation of a room depends on many different factors:

Early Reflections - The first reflection of a sound off an object/wall that reaches the listener's ear milliseconds after the direct sound does. Early reflections enable the listener to quickly determine room size.

Reverb time - A larger enclosed space produces a larger reverb time. However a larger reverb time requires a louder source sound to allow the sound enough energy to be reflected around a large space.

Absorption - When a sound reflects of a wall/object some of the sound is absorbed into the material that the wall/object is made of. Different materials absorb different ranges of frequencies as high frequency have a smaller wavelength than lower frequencies. The greater the absorption in the room equals a smaller reverb time. 

Human Hearing

Localisation and Direction:

Inter-aural Time Differences (ITD) - This is one of the cues that helps humans perceive direction of sound, it is the difference in the time of arrival of a sound between the two ears. If a sound is coming from a source on the left then it will arrive at the left ear before the right and it is this difference in time that helps the brain determine the direction of a sound. 

Inter-aural Intensity Differences (IID) - This is another cue that helps humans perceive direction of sound, it is the difference in intensity of a sound between the two ears. If a sound is coming from a source on the left then it will be louder in the left ear than the right and it is this difference in intensity that helps towards the localisation of sound. 

Head Related Transfer Function (HRTF) - Is the way in which sound waves physically interact with the human ear. The shape of the outer ear, including parts such as the pinna, helps to direct sound into the ear canal. The differences in the physical interaction of a sound wave between the ears alongside IID and ITD is how humans localise sound sources.

Physical Factors of Sound

Amplitude - the maximum deviation of the pressure waveform from the average, unit N/m squared.

Frequency and Pitch - Frequency is the number of cycles that a sound waves make per second and is measured in Hertz. The higher the number of cycles (frequency) equals a higher pitch. The human hearing is capable of hearing from 20Hz to 20,000 Hz, however damage to hearing may cause this range of frequencies to be smaller.

Phase - Time or angular difference between one signal an another.

Resonance - The vibration of an object or medium at a specific frequency.

Velocity - The speed of time in air under normal conditions is 340m/s.

Wavelength - The length of the physical wave in metres.


Measurement of Sound:

Intensity - The "concentration" of sound, unit N/m squared or Watts/m squared.

Loudness - The subjective "measure" of SPL and has the unit phon.

Sound Pressure Level - Sound can be described as variations in air pressure, SPL uses the unit dB. SPL is a ratio between the actual sound pressure and a reference level usually the threshold of human hearing. 

Propagation of Sound:

Diffraction - Sound bends easily around obstacles that are of a similar size or smaller than the wavelength of the sound. Lower frequencies bend/diffract more freely around obstacles because of their longer wavelength.

Humidity - This has the decreasing the velocity of a sound. Dry air absorbs more energy than moist air, thus attenuates the sound to a greater level. 

Pressure - Air pressure has little effect on the velocity of sound. 

Refraction - When sound travels from a less dense medium to a more dense medium it bends in towards the normal. When it travels from a more dense medium to a less dense medium it bends away from the normal. 

Temperature - The speed of a sound increases at around 0.6m/s for every degree rise in temperature. 

Super Audio Compact Disc (SACD)

The super audio CD has been available since 1999 and is a dual-layer disc that offers 16-bit stereo, which is used for conventional CD’s and also a high-resolution six-channel mix. The benefit to this CD is that it can be played through normal CD players, however in order to playback the SACD in surround the consumer must use a SACD player or DVD player that supports SACD.

This format is precisely what the music industry needs if the 5.1 surround sound system was to become a popular playback format for music reproduction: a medium which can playback normal stereo material but also surround sound material. However, this compact disc is used rarely in the music industry. Jack schofield (2007) from the Guardian Newspaper states some interesting findings while investigating this subject in more depth:

"The International Federation of the Phonographic Industry (IFPI) says only 2m SACDs were sold last year (2006), compared to 1.7bn CDs. (This may understate sales, because IFPI doesn't track hybrids separately, and almost all SACDs are now hybrids. But how would we know if buyers were going to play the SACD layer?)"

Even though the IPFI do not track hybrids, which are both CD and SACD, the sales figures for non-hybrid SACD's are incredibly low compared to CD, especially considering these figure were taken seven years after its release. It can be seen from this that the SACD is failing to become the new standard medium for storing music. There are a few reasons as to why the release of this new compact disc was not successful. 1999, was the same year that peer-to-peer file sharing service Napster began, this allowed people to acquire music for free and share it via MP3 files. Although this service was shut down in 2001 due to the copyright infringement it was causing, many other internet based services would take its place and begin the uprising of music piracy. 

The SACD was competing in a battle that it couldn't win. Two new ways of acquiring music were available to the public, both released in the same year. One where the consumer could access their music for free via low quality MP3 files which could be stored on your computer in mass quantities. And the other a compact disc, which would still cost the consumer money and they might even have to purchase a new playback system to enjoy the high quality surround sound that it can offer. When faced with this choice, the consumer is obviously going to choose the option where they can access their music for free. Unfortunately this is obviously had a detrimental affect on the fate of the Super Audio Compact Disc.