Ex Machina Inspiration

Ex Machina introduced me to the future controlled by AI. This film was not a Back To The Future in terms of new products, but gave a more futuristic picture to our lifestyle and use of spaces in the future.  The movie showed a futuristic house, where technology was minimal. The visible objects were either pieces of art or furniture. Thus, technology was more integrated with the house becoming less visible. Very close to our project which requires us to design speakers for invisible sound. A futuristic concept as demonstrated in ex-machina. I sketched art work integrated speakers attached to the wall inspired from this movie


Market Research

market analysis.png

We worked on categorising the competitors into general zones by plotting their audio products against these two axes, Portability and Innovation. We realised that Samsung, as well as the nearest competitor, Sony, are both moving towards more innovative and less portable audio solutions. The other competitors that hold a large market share in Asia are mostly congregated at the lower half of the graph.

Human Auditory Perception and how the Human Ear Works

By Rosanne Chong

Research have shown that perceived loudness by humans varies to a large extent with frequency and sound-pressure level. A low frequency sound would require a much higher sound pressure level to sound as loud as a high frequency sound. In other words, for the same sound-pressure level, a higher frequency sound would be perceived as much louder than a lower frequency sound.

The level of sound also affects human perception of pitch. For high frequencies, the pitch goes up as the level of sound is increased and for low frequencies, the reverse occurs. By understanding the complex relationship between quantitative measures of sound like frequency and sound-pressures with the human perception of sound, one can apply such knowledge to increase the quality of sound of the invisible speakers to be designed.

The space occupied also plays a part in affecting human auditory perception. In large enclosed spaces, such as auditoriums and music halls, surfaces might produce reflections of a high enough sound level to be perceived as audible echoes. This would affect the user’s perception of sound as compared to when they hear the same sound in an open space or a small narrow space. One interesting thing to note would be that, large enclosed spaces might not necessarily lower the quality of sound perceived due to the numerous unwanted echoes produced. If well designed to give lateral reflections of appropriate levels and delays, such spaces can add a sense of spaciousness to the music for the audience, thus improving the experience of the users through careful manipulation of their perception of sound through altering the space.

Moving on to the specifics of how the ears work to perceive sound, sound waves entering the ear canal would cause the ear drum to vibrate, which will in turn move the tiny chain of bones in the middle ear. The final bone in this chain of bones would then knock on the membrane window of the cochleas, making the fluid inside move. This fluid movement then triggers a response in the hearing nerve. One fascinating fact is that the outer hair cells of the mammalian cochlea seems to contribute greatly to the amplification of sound. Perhaps more in depth understanding of this could lead to further explorations in our speaker design.



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Audio Engineering

By Shariq Farooqui

During my research I looked at audio engineering, which involved understanding how sound is recorded, manipulated and reinforced. Speakers essentially just engineer sound for our listening. First I studied the seven characteristics of sound namely, frequency, phase, velocity, amplitude, harmonics, wavelength, envelope which are manipulated in order to produce sound. These characteristics are important building blocks of audio engineering.

The next aspect of sound engineering I looked at was equalization of sound. It involves adjusting the balance between frequency components within an electronic signal. Equalizers can correct problems posed by a room’s acoustics, rooms might have an uneven frequency response especially due to standing waves and acoustic dampening. The frequency response of a room may be analysed using a spectrum analyser and a pink noise generator for instance. Then a graphic equalizer can be easily adjusted to compensate for the room’s acoustics. Such compensation can also be applied to tweak the sound quality of a recording studio in addition to its use in live sound reinforcement systems and even home hi-fi systems.

Then I looked at sound production and manipulation through digital signal processing. Audio processing covers many diverse fields, all involved in presenting sound to human listeners. It is very useful in high fidelity music reproduction. It helps manipulate the characteristics of sound in order to reproduce sound. When designing a digital audio system there are two questions that need to be asked: (1) how good does it need to sound? and (2) what data rate can be tolerated?


  1. Audio Engineering 101: A Beginner’s Guide to Music Production By Tim Dittmar
  1. Equalization of Sound
  1.  Understanding the low pass and high pass filters in sound equalization
  1. Processing Audio Signals
  1. Audio Engineering Explained edited by Douglas Self
  1. Compositional models for signal processing – Perspectives from audio processing by Virtanen, T.
  2. Performance Analysis of Parallel Signal Processing Algorithms in Audio Mixing Systems By Jiri Schimmel Faculty of Electrical Engineering and Communication
  1. Introduction to Sound Processing by Davide Rocchesso
  1. Digital Audio Processing by Udo Zolzer
  1. Switched Capacitor Bandpass Filter for use in Home Audio Parametric Equalizer By John R. Ambrose, Douglas Cox, Cecil Solomon

Sound propagation, Reflection and Perception

by Daniel Tay

The focus of my research was on the physics behind the propagation of sound in a small room setting, and how the same sound is perceived by the user. This setting best describes the home environment that our group is designing ‘invisible sound’ for. Such a specification of the room setting is vital, as the acoustics of small spaces defer greatly from that of larger venues such as concert halls.


An important aspect of the sound quality is based on perception. Acousticians then conduct experiments to quantify such qualities scientifically. An acoustically good room sounds ‘live’, and the converse, ‘dead’. The most dated method of quantifying this is the Reverberation Time, where a high RT number indicates better acoustic quality. Acousticians such as D’Antonio and Eger (1986); Geddes (2002); Jones (2003); Kuttruff (1998) have questioned this given that smaller rooms typically have smaller RT numbers. They propose that sound reflection takes on even greater importance in the overall listening experience, which brings us to the next section.


Toole (2008) talks about the need to delve deeper beyond simple measurements. He too concurs with the former group of acousticians about the influences of early reflected sounds. He further proposes that the knowledge of ‘directivity and off-axis frequency responses of loudspeakers and the directional reflective, diffusive, and absorptive characteristics of materials at the points of first reflections are essential’.


Toole (2008) writes about a cognitive effect called the ‘precedence effect’ of the brain localizing in the presence of multiple different sound sources. The results gathered from different research is presented as follows- Firstly, stronger reflections shift the position of the source and make it seem larger. Secondly, reflections and delayed reflections change the timbre of the perceived sound, adding coloration and resonance that may affect the listening experience in both ways. Humans perceive such effects most if the reflections are in the median plane.


The timing in between reflections too affect the listening experience. Haas, Gardner, Lochner and Burger all found that the first reflection dominates this experience. However, the timings between subsequent reflections determine if these are heard as ‘spatially separated auditory images’ (long delay) or as a single image (short delay). Also, the volume of the delayed sound determines how ‘spacious’ the room sounds.


In relation to our project, it is clear that for an even perception of sound across the entire living space, it is necessary to consider the acoustics of the individual spaces such as the kitchen, bathroom and hallway that make up the entire living space. Factors such as the volume of the room, the presence of strongly sound-absorbing curtains and furniture in the living room in comparison to hard table tops in the kitchen do affect the listening experience. Sound sources should therefore cater for and smoothen out these localized irregularities to create an excellent, across-the-board listening experience. If possible, the sound system could even take advantage of reflections and utilize them to enhance the listening experience.




Acoustics of rooms

ITU-R Recommendation BS.775–2 (2006). “Multichannel Stereophonic Sound System

With and Without Accompanying Picture.”




Toole (1986). “Loudspeaker Measurements and Their Relationship to Listener Preferences,”

  1. Audio Eng. Soc., 34, pt. 1, pp. 227–235; pt. 2, pp. 323–348.




Schroeder, M.R. (1954). “Statistical Parameters of the Frequency Response Curves of

Large Rooms,” Acustica, 4, pp. 594–600. Translated from the German original in

  1. Audio Eng. Soc., 35, pp. 299–306 (1987).



Schroeder, M.R. (1996). “‘Schroeder Frequency’ Revisited,” J. Acoust. Soc. Am., 99, pp. 3240–




Baskind, A., and Polack, J.-D. (2000). “Sound Power Radiated by Sources in Diffuse

Field.” 108th Convention, Audio Eng. Soc. Preprint 5146.



Schultz, T.J.  (1983). “Improved Relationship between Sound Power Level and Sound Pressure

Level in Domestic and Offi ce Spaces,” Report No. 5290, Am. Soc. of Heating, Refrigerating

and Air-Conditioning Engineers (ASHRAE), prepared by Bolt, Beranek, and

Newman, Inc.



Hodgson, M. (1983). “Measurements of the Influence of Fittings and Roof Pitch on the

Sound Field in Panel Roof Factories,” Applied Acoustics, 16, pp. 369–391.


Gover, B.N., Ryan, J.G., and Stinson, M.R. (2004). “Measurements of Directional Properties

of Reverberant Sound Fields in Rooms Using a Spherical Microphone Array,”

  1. Acoust. Soc. Am., 116, pp. 2138–2148.



D’Antonio, P., and Eger, D. (1986). “T60—How Do I Measure Thee, Let Me Count the

Ways,” 81st Convention, Audio Eng. Soc., Preprint 2368.



Geddes, E.R. (2002). Premium Home Theater: Design and Construction. GedLee LLC, Novi,

Michigan, USA. www.gedlee.com.



Jones, D. (2003). “A Review of the Pertinent Measurements and Equations for Small

Room Acoustics,” J. Acoust. Soc. Am., 113, p. 2273 (abstract only). Personal communication:

presentation text from the author.



Kuttruff, H. (1998). “Sound Fields in Small Rooms,” 15th Conference, Audio Eng. Soc., Paper




Benade, A.H. (1984). “Wind Instruments in the Concert Hall.” Text of an oral presentation

at Parc de la Villette, Paris; part of a series of lectures entitled “Acoustique,

Musique, Espaces,” 15 May 1984 (personal communication).


Precedence Effect


Gardner, M. (1968). “Historical Background of the Haas and/or Precedence Effect,”

  1. Acoust. Soc. Am., 43, pp. 1243–1248.




Localization and Listener Perception


Gardner, M.  (1969). “Image Fusion, Broadening, and Displacement in Sound Localization,”

  1. Acoust. Soc. Am., 46, pp. 339–349.





Gardner, M. (1973). “Some Single- and Multiple-Source Localization Effects,” J. Audio Eng.

Soc., 21, pp. 430–437.



Haas, H. (1972). “The Influence of a Single Echo on the Audibility of Speech,” Doctoral

dissertation, University of Göttingen. Reprinted in J. Audio Eng. Soc., 20, pp. 146–

159, 1972. A reprint of a 1949 translation of Haas’s PhD dissertation.


Lochner, J.P.A., and Burger, J.F. (1958). “The Subjective Masking of Short Time-Delayed

Echoes by Their Primary Sounds and Their Contribution to the Intelligibility of

Speech,” Acustica, 8, pp. 1–10.



Benade, A.H.  (1985). “From Instrument to Ear in a Room: Direct or via Recording,” J. Audio

Eng. Soc., 33, pp. 218–233.



Olive, S.E., and Toole, F.E. (1989a). “The Detection of Reflections in Typical Rooms,”

  1. Audio Eng. Soc., 37, pp. 539–553.



Shinn-Cunningham, B.G.  (2003). “Acoustics and Perception of Sound in Everyday Environments,” Proc.

3rd Int. Workshop on Spatial Media, Aisu-Wakamatsu, Japan. http://cns.bu.edu/




Rakerd, B., Hartmann, W.M., and Hsu, J. (2000). “Echo Suppression in the Horizontal

and Median Sagittal Planes,” J. Acoust. Soc. Am., 107, pp. 1061–1064.



Meyer, E., and Schodder, G.R. (1952). “On the Infl uence of Refl ected Sound on Directional

Localization and Loudness of Speech,” Nachr. Akad. Wiss. Gottingen, Math.

Phys. Klasse IIa, 6, pp. 31–42.


Textbook Source


Toole, F. E. (2008). Sound reproduction: Loudspeakers and rooms. Taylor & Francis.









Existing Technology

By Tan Jay Sern

Speakers have taken many different forms ever since the invention of the horn in 1880. The standard speakers used today are the dynamic loudspeakers that uses the concept of magnetic field to produce sound. These dynamic loudspeakers has evolved tremendously since being invented in the 1920s. They include floorstanding speakers, bookshelf speakers, in-wall speakers, on-wall speakers, in- ceiling speakers, portable-bluetooth speakers, and levitating speakers. In relation to the project, I have specifically researched on existing products with unique features and functions that reflect the current trend of listening to music. Taking into consideration invisible sound, some of these products are non-conventional products with the purpose of hiding the fact that they play music as well.

Funtionalitylevitatin speaker

1.  Levitating Speaker

  • Bluetooth speaker that rotates over a base.
  • Uses strong magnets to keep the speaker afloat.
  • Extremely portable and aesthetically pleasing.


2. Compact portable speaker (Libratone Zipp)libratone

  • Able to connect to Bluetooth and Wifi.
  • Soundspace linking, meaning ability to link up with a maximum of 16 speakers on a wireless network.
  • 360 sound projection.
  • Allows direct streaming of up to 5 radio stations through wifi.
  • Hand gesture detection. Hover hand over speaker to mute it.


3. Multiroom portable speaker (Kien Speakers)kien

  • Made of many small and portable Bluetooth speakers that can be placed all around your home.
  • Speakers will automatically start playing when phone is nearby meaning you don’t have to switch speakers when you enter a different room.

Room integration Speakers

1. In-wall/ceiling speakers (Sonance/Stealth Acoustics)invisible sound

  • Speakers that are installed directly in the dry walls which is then touched up and covered with paint.
  • Completely invisible.


2. Modular Speaker system (Soundhive)hive

  • Modular means that you can have a choice of using just 1 speaker or a whole wall of them.
  • Speakers can be extended and pivoted independently according to wall structure.
  • Aesthetically pleasing and is able to camouflage as a wall decoration.


3. JMC Soundboardjmc soundboard

  • A natural sound amplifier that blends well into any environment.
  • Speaker is placed behind this piece of wood which then disperses the sound throughout the room.
  • Uses the concept of wood contours to produce quality sound.


Speaker Integration (Multipurpose speakers)

1. In-Ceiling lighting and audio system (Klipsh Lightspeaker)lightspeaker

  • Speakers integrated into the lighting system that replaces the conventional ceiling lightbulb.
  • Uses a transmitter and remote control to control the lights and speakers
  • Connect your device to the transmitter using an AUX cable to play song.

2. Sound Garden                      sound garden






3. Wireless Music/Phone Speaker Showerhead
shower speaker





This research is also to study current trends in the evolution of speakers. It provides me a general insight on where SAMSUNG is able to fit in. I noticed a strong trend of shifting towards portable bluetooth speakers with multiple functionality to provide a greater hearing experience at home. SAMSUNG invisound definitely has strong potential in exploring this area as it eases speaker integration in everybody’s home.


  1. Sonance Invisible Sound
  2. Stealth Acoustics
  3. Om-one Levitating Speaker
  4. JMC Soundboard
  5. Klipsh Lightspeakers
  6. Libratone
  7. Garden Speaker
  8. Soundhive
  9. Showerhead Speaker
  10. Kien Speaker
  11. Sony Lightspeaker
  12. History of Speakers
  13. Types of Speakers
  14. Loudspeaker
  15. http://www.designswan.com/archives/17-cool-and-unusual-speakers-that-look-great-and-sound-awesome.html
  16. http://weburbanist.com/2009/12/17/amazing-audio-40-sexy-speakers-sweet-system-designs/
  17. http://coolmaterial.com/roundup/unique-speakers/
  18. http://www.demilked.com/unusual-cool-speakers/