Audio Pixels – The Future of Speaker Design? by Alec Wren | Oct 30, 2014

This is an old article.
Still a good summary and nice to read.
Back in 2014 it was a scientific vision.
Now in 2016 it turnes into reality.


Audio Pixels – The Future of Speaker Design? by Alec Wren | Oct 30, 2014



First Major innovation in audio speakers in nearly 80 years

Audio Pixels Limited is on the verge of producing what they are claiming to be the “First major innovation in audio speakers in nearly 80 years.” Audio Pixels have developed a revolutionary technological platform for reproducing sound, enabling the production of an entirely new generation of speakers that will surpass performance specification and design demands of the world’s top consumer electronics manufacturers. The Australian based company was founded in 2006, and is publicly traded on the Australian Stock Exchange (ASX) under the trading code AKP (at the time of writing, their share price was at $10.35).
The Audio Pixels website states:
“Our patented technologies (principle patents in national phase in 13 countries), employ entirely new techniques to generate sound waves using low cost micro-electromechanical structures (MEMS). This innovation enables the production of speaker products that deliver performance that is many orders of magnitude better than conventional speaker technologies, all in an affordable package that is roughly only one millimetre thick!”
These claims are big to say the least. One wonders how a speaker “one millimetre thick” could produce a wide range of frequencies (especially the lows), and at semi-decent volumes. Skeptical I am, let’s take a further look into this company and their technologies.


Audio Pixels Business Model

Audio Pixels plan to produce and sell a single type chip that can be used either as a standalone speaker, or cascaded in any multiples up to 64 units of the same chip. The number of chips is determined by the application in question, and the requirements of the manufacturers audio specifications based on their target market. For example:
Mobile Phones: 1 single chip would be sufficient
Television: 2-6 chips recommended
The modular paradigm is a new thing for the audio industry, which today expends vast resources designing and specifying new drivers, acoustic chambers and drive electronics for each device.
“This innovative approach not only facilitates maximum flexibility to its customers, it further enables the Company to calibrate on the design and production on a singular product model, maximizing economies of scale, while limiting overhead associated with multiple versions of products.”


Demand for innovation in audio speakers

Audio Pixels are hoping to fill what they see as a gaping demand for innovation in the speaker market. They see the key challenge for the most part being that conventional speaker technologies remain rooted in the original voice coil inventions of Alexander Graham Bell. The limitations of this technology prohibit the delivery of high quality sound in smaller packages. Audio Pixels see their revolutionary technology as changing this paradigm, providing a completely fresh approach to speaker design.


How Does an Audio Pixel Speaker Work?

An Audio Pixels speaker is a MEMS (micro-electromechanical structure) chip roughly 1mm thick. This chip replaces conventional speaker driver(s), enclosure, as well as the electronic circuitry associated with converting the digital signal feed to analog.
The Audio Pixels speaker chip is not only radically smaller; it consumes a fraction of the power to produce far better acoustic performance (less distortion, clearer/crisper sounding, and more accurate sound reproduction).
At the heart of Audio Pixels technology is “An innovative, high impedance structure based on high-efficiency driving mechanism which is capable of producing remarkably high air pressure despite its diminutive size.” Audio Pixels claim their revolutionary structure can produce on average 10 times the pressure of a conventional speaker of the same surface area, amplitude and frequency.
The acoustic principles underlying the Audio Pixels speaker technology is known as “Digital Sound Reconstruction” (DSR), which predominantly generates the desired sound waves by using arrays of pressure generating drivers. The elegant combination of advanced fluid manipulation techniques, miniaturization technologies, and the driving mechanism of Audio Pixels has enabled the advantage of DSR to become actualised, and bought into the consumer markets.
The sound pressure generated by an Audio Pixels speaker is proportional to the number of micro-speakers (Audio Pixels). By varying the pulses over time, they can produce different frequencies.
“The net linearity of the array comes from linearity of the acoustic wave equation and uniformity between individual speakers. The overall non-linear components in the generated sound wave have a direct relation to the number of micro-speakers in the device.”


What Advantages does Audio Pixels Technology provide Electronic Manufacturers?

Form Factor: Today’s consumer products are gearing more and more towards aesthetically pleasing devices that are smaller, and lighter. While industry has been able to shrink form factors of all other electronic devices, one of the last remaining barriers continues to be speakers which remain large, power heavy, and restrictive. Audio Pixels combat these problems by providing a small, portable, and low-energy speaker design.
Reduce Design Complexity: Current speaker designers place great importance on design parameters via opinions of sound specialists with the all mighty “golden ears”. Although well trained ear experts exist, sound is a very subjective experience. This approach translates into a long and expensive design process. Audio Pixels place heavy importance on using measurable, scientific methodologies for their design process, with the ability to make adjustments to their speakers using computer code.
Reduced Power Consumption: Power consumption is becoming increasingly problematic as personal electronic devices such as mobile phones and laptops are increasing in performance and energy demands. Conventional analog speaker drivers can be viewed as the most inefficient transducer around, converting on average only 1% of their electrical energy into acoustic energy. Audio Pixels claim their speakers are 10x more power efficient without compromising quality, or increasing complexity or cost. Audio Pixels see their technology being able to reduce the power needs of a mobile phone, 30% of which is used by the speaker. Audio Pixels would reduce this to “less than 10 per cent.”
Quality: There is big demand for speakers that meet current market design trends, but that are also capable of producing high quality sound. The current voice coil speaker manufacturers face the dilemma of maintaining their high standards of audio reproduction, whilst meeting the consumer demands for better, and smaller products. Audio Pixels claim their speakers offer performance that is “incomparable” to existing speaker technologies of similar size. Therefore, they can meet the demands of consumers whom want small and stylish products, without compromising the sound quality.
Excellent Impedance Matching: Audio Pixels maximise energy conversion (from electrical to acoustic). They claim an efficiency limit of 60%, which is roughly 60 times better than a conventional speaker. This improved impedance matching allows the speaker to increase the loudness (or SPL) significantly compared to similar conventional speakers of similar size.
True digital reproduction: Unlike conventional speakers which require the membrane to compliantly travel varying distances and speeds, Audio Pixels micro speakers are required to perform the exact same simple function. i.e. work, or don’t work at any given time. When the Audio Pixels speakers are working, they travel at the same speed over the same displacement. Audio Pixels claim their speakers “stop on a dime”. The signal is initiated and terminated within one clock cycle.
Low distortion levels, broader frequency range: Audio Pixels claim their DSR technology can produce a much broader frequency range, and a frequency response that is perfectly flat. Distortion levels will be a fraction of that of a conventional speaker, at levels well below the human detection threshold.

A size comparison of an Audio Pixel chip with an American coin.


Summary

When something sounds too good to be true, it all too often is. In the case of Audio Pixels, we have a company claiming to be on the verge of a monumental breakthrough in speaker design that could revolutionise the audio industry. I myself remain skeptical at this point. I would require a physical demonstration of the product, to hear for myself if these claims are at all valid.
But in the ever evolving, fast progressing technological age we find ourselves in, breakthroughs do happen. Every now and then a company comes out of the works with a product that changes everything. Audio Pixels could be that company, in terms of changing the way millions or even billions of people worldwide experience audio through their electronic devices.
I will endeavor to keep a close eye on the progress and developments of Audio Pixels. The thought of revolutionising the quality of the audio experience for individuals on such a scale is exciting, and I welcome Audio Pixels to bring fourth such a product.