Hearing Assistance

I don’t find having a hearing disability fun! Anonymous

Modern hearing aids, with rechargeable batteries and T-coils allowing use of hearing loops.


This weblog post is about technical devices that will ease the difficulties a hearing disability places on a person. These devices can only ease a burden, they cannot eliminate it, Hearing loss will always result in deprivations.

This is the second version of this post, with thanks to Art Vaughan, for finding 14 situations that needed to be enhanced in various ways. There are undoubtedly more. Thank you, Art!

Modern hearing aids are computerized electroacoustic systems that transform sound as it exists in a user’s environmental into sound that can be perceived, using audiometric and cognitive rules. Modern devices also utilize digital signal processing to improve speech intelligible, yet comfortable for the user. Such signal processing includes feedback management, wide dynamic range compression, directionality, frequency lowering, and noise reduction.

Hearing aids are still equipped with the basics from a century before: a microphone, amplifier and a receiver. Hearing aid manufacturers, confusingly, use receiver to refer to the micro speaker – a sender – inside each hearing aid. The microphone senses the environment, listening to sound vibrations in the normal range of human hearing. The amplifier processes signals from the microphone, and the receiver sends the signal to the ear.

Since the audio circuit and the additional control circuits are fully digital on modern hearing aids, they can be connected to a computer. Characteristics can then be adjusted individually, provided the hearing professional knows what they are doing. It is often easier to implement circuits digitally than to construct equivalent analog circuits. A typical example is that specific frequencies can be amplified more than others to provide better sound quality. Users can select between multiple programs that operate automatically and adaptively. Among the advantages are: reduced acoustic feedback and background noise and the use of multiple microphones to improve spatial awareness. Frequency transposition allows frequencies that a user may not hear to be reconstructed in frequency regions where hearing is better. Control signals on a hearing aid on one ear can be sent wirelessly to the control circuitry in the hearing aid on the opposite ear to ensure that the audio in both ears is either matched directly or that the audio contains intentional differences that mimic the differences in normal binaural hearing to preserve spatial hearing ability.

At one time streamers were popular. These were small devices worn like a pendant, that allowed audio signals to be sent wirelessly to and from other external devices, such as music players. This capability is now built into apps found on smartphones. With the addition of speech recognition and internet capability in the mobile phone, the wearer has better control over communications, and in many more situations than with hearing aids alone. Voice activation – think Siri – has becoming more common and is now used everywhere.

Digital hearing aids have existed since 1984. The first practical, wearable, fully digital hearing aid was invented by Maynard Engebretson, Robert E Morley Jr. and Gerald R Popelka. Their work resulted in US Patent 4,548,082: Hearing aids, signal supplying apparatus, systems for compensating hearing deficiencies, and methods. The patent was issued 1985-10-22, and expired 2005-10-22. This patent formed the basis of all subsequent fully digital hearing aids.

A telecoil is a tiny copper wire coiled around a metal rod. It is used to capture electromagnetic waves, much like an antenna. Circuits inside a hearing aid will convert these waves into an audio signal. Telecoil listening systems bypass hearing aid microphones, to eliminate most background noise and to transmit a clear audio stream.

At one time acoustic feedback was a major issue for hearing aids wearers when using the telephone. With a telecoil, hearing aid users can tap directly into the electromagnetic signal instead of the acoustic one, preventing feedback.

The last significant change has been the use of rechargeable batteries. These are charged by placing the hearing aids in their case, and then attaching the case to a power source, using a connector. In Europe, the use of USB-C connectors on new devices, including hearing aid cases, will be required by the end of 2024.

People with moderate-to-profound sensorineural hearing loss are often provied with a cochlear implant (CI) neuroprosthesis. This is surgically implanted. It bypasses acoustic hearing by direct electrical stimulation of the auditory nerve. Therapy teaches CI users how to interpret signals as speech so they understanding speech better in both quiet and noisy environments. CIs can be equipped with telecoils.

In Australia, Europe, North America and many other places in the world, hearing loops have been mandated for use in spaces used by the public. Previously, some jurisdictions initially allowed other, cheaper technologies. Unfortunately, this meant that hearing loops were an afterthought to disability infrastructure.

In contrast to other approaches, some of the advantages of hearing loops combined with telecoil equipped hearing aids are: there is no maximum number of users that can be served at a venue, they are simple to use, improve the signal-to-noise ratio (SNR) and signal quality, reduce background noise and reverberation, allow users to retain their dignity and privacy by not requiring them to remove hearing aids to use of forms of hearing augmentation. Despite this, there can be legitimate complaints that hearing loops are not designed for listening to music, because of distortion at higher frequencies.

Joseph Lazarevich Poliakoff (1873 – 1959), a Ukrainian-born British telephone and sound engineer and inventor, particularly of hearing aids. He founded the Multitone Electric Company in 1931. They produced their first hearing aid, a desk-top model, in 1933. In 1937,  Poliakoff was issued a patent for an induction-loop hearing assistance system. It remained valid until 1958, when it entered the public domain.

When a telecoil is activated, it senses magnetic fields, replacing (sometimes supplementing) the microphone, sensing for sounds. Telecoils can be used with hearing loops, individual amplifiers and smartphones.

In Norway, and undoubtedly many other places, no landlines exist, since all phones are connected to the mobile network. Telephone providers can supply a device with limited functionality that looks like a landline. It is permanently plugged into an electric circuit. It also costs about twice as much as a smart phone. There are also dumbphones that are specifically designed for elderly users. Acoustic coupling settings allow a phone to be used normally, with paired hearing aid microphones automatically picking up sound coming from the phone. Cellphones with a M rating of 3 or 4 have this capability. Bluetooth is also used for communication between hearing aids and a phone. This requires the two devices to be paired.

Some phones have telecoils built in. These can be set to send magnet signals to hearing aids without using microphones. These can improve the signal-to-noise ratio while eliminating feedback distortions. Phones with a telecoil capability have a T rating of 3 or 4 have this capability.

A hearing loop = audio induction loop = audio-frequency induction loop (AFIL) is assistive listening technology that uses hearing aid telecoils.

We have a hearing loop at Cliff Cottage, an electrical cable with a pair of 0.75 mm2 = 19 AWG wires. This type of cable is typically used for extension cords for lamps. The hearing loop was placed around the perimeter of our living room in the ceiling . It is almost 30 m = 100 feet long. The loop starts and ends in a wall connector, close to where a hearing loop amplifier is located. A hearing aid will be able to pick up audio inside a hearing loop, as well as up to several meters outside of it.

The loop was first installed in 2009, by the local branch of NAV = Hub (literally), the Norwegian super-agency that, in addition to far too many other duties, provides assistive devices to residents. Before fitting new ceiling tiles in 2021, I took it down and reinstalled the loop after the tiles were in place. Later, I discovered that when such a system is installed in a new house, it is hidden in the floor. Unfortunately, I was unaware of this at the time, because I could have placed it in the floor when I replaced the living room flooring in 2022.

On the left is the original Univox DLS-380 hearing loop amplifier with wiring attached. To the right is a S/PDIF splitter/converter. A S/PDIF Toslink optical audio stream is taken from a television and sent to the splitter. There the signal is split into two analogue streams of stereo signals. One stream goes to an active bass speaker, that plays low frequency founds. Mid-frequency and high-frequency sounds are sent in stereo to two (L & R) bookshelve speakers.

Working forward from a television’s S/PDIF Toslink digital optical connectors, a stereo digital audio stream was sent to a S/SPDIF splitter, that sent two RCA analogue signal streams onward. One stream was sent to the original Univox DLS-380 hearing loop amplifier. That amplifier sent the audio to the loop system. In addition, another stream was sent using RCA connectors to an active bass speaker, that plays low frequency sounds. Mid-frequency and high-frequency sounds were then sent in stereo to two (L & R) bookshelf speakers.

The current system has the same function, but with details that differ. The CLS-5 telecoil amplifier can operate with a wide range of operating voltages. In residential/ institutional/ commercial applications, it will most likely use 110-240 VAC. However, it can also be fitted into buses and recreational vehicles as well as boats, where it most likely will use 12-24 VDC. It comes with optical (digital) and coaxial (digital and analogue) inputs. It also has a setscrew that allows for adjustment of time delay between the audio and video signals (TV Sync). It provides easy connections to modern (and not so modern) flat screen plasma/ LED/ LCD TVs.

When these components were replaced at the end of 2023, none of the replacement units came with RCA connectors. HDMI, S/PDIF and USB-C audio connectors were common to both the (new) smart television and the sound bar. While the new Univox CLS-5 amplifier works with several types of connectors, the installer said that S/PID Toslink optical connectors created the least challenges. So these were used.

Once again a single digital audio stream was sent from the television to a splitter. From the splitter, two identical audio streams emerged. One was sent to the hearing loop amplifier, while the second audio stream was sent to the sound bar. Both used digital Toslink optical connectors. .The splitter is powered with mains electricity.

This cable generates an electromagnetic field throughout the looped space which can be picked up by: 1) telecoil-equipped hearing aids, 2) cochlear implant (CI) processors, and 3) specialized hand-held hearing loop receivers for individuals without telecoil-compatible hearing aids. So while this technology was installed specifically for one person using one technology, it is equally useful for other people, most likely visitors, using the other hearing assistance technologies.

In order to transmit the clearest possible sound source to a hearing-impaired listener, free of distracting noise, a hearing loop carries baseband audio-frequency signals without a carrier signal.

Installing the cables is not difficult, and can be installed by almost anyone. However, one should read amplifier documentation, and understand the process, before doing so. I am unsure of the reason for this, but the user’s manual states that one should twist the wires 180 degrees at some point. In this way a wire that was on the right at the beginning, will be on the left once the wire is turned, and vice-versa.

The Hearing Loss Association of America (HLAA) has commented on hearing loops:

Loop technology was pioneered in Europe where it is widely embraced and highly successful. When hearing accessibility in the United States was made a requirement of law in 1990 under the Americans with Disabilities Act, no distinction was made between loop systems and less expensive FM or IR systems. Although the ADA did require that systems provide access to “effective communication,” people with severe to profound hearing loss—for whom FM and IR systems often fall short—were slow to mobilize advocacy for hearing loops.

The ADA Standard for Accessible Design was updated in 2010 requiring that for renovation and new construction that at least 25% of receivers provided are hearing aid compatible—meaning that users do not have to remove their hearing aids to use the system. This dramatically raised the interest in and availability of hearing loops because loops are the only assistive listening systems that connect directly to telecoil-enabled hearing devices. (End of HLAA comment)


Tinnitus is the perception of sounds that are not the result of an external source. There is no cure for this, but there are ways to manage the condition.

Despite being a person who was diagnosed with tinnitus at the age of about 50 in 1998, I have never considered using hearing aids as a treatment. I have had one counseling session. However, as a teacher I have regularly attended seminars with a focus on assorted disabilities, including hearing.

My approach to self medication has been to engage in activities that require concentration. This puts tinnitus into the background. At other times I rely on low intensity music. Over the past 25 years I have tried various genres. As I approached 60, I reduced – almost eliminated – listening to classical music and started listening to less melodic music. These are better able to mask my tinnitus. When tinnitus is at its worst, my music choices are the trashiest metal. My understanding is that everyone is different.

Many hearing aids offer some form of tinnitus relief. Often this is an app delivered to the hearing aids, from a phone. If this is the case, it is important that the phone and hearing aids are compatible with each other. Sometimes, it is a computer program inside the hearing aid, that has to be activated. It is also important to know if this program can be altered to reproduce the specific sounds needed by the user. Sounds that are enhanced for a particular users are more effective for therapy than more generic sounds.

Cognitive behavioural therapy (CBT) focuses on thoughts, beliefs and attitudes to improve emotional responses to help a person develop a strategy to help a person cope with a current problem. It was originally developed to treat depression, but its use has been expanded to include the treat other conditions, such as tinnitus.

MindEar is an app that provides CBT through a chatbot. The goal is to empower people so they regain more control over their lives. Often the use of such an app is combined with counseling with a clinical psychologist, either in person or online.

People with tinnitus often enter negative thought cycles. Many people need some form of counselling to help them cope with it.

Hearing aid styles

There are several hearing aid styles. Small hearing aids may be less visible but they may lack the power to improve hearing. These are referred to as Completely in the canal (CIC) or mini CIC. This is molded to fit inside an ear canal, but is only useful for mild to moderate hearing loss. One of its advantages is that it is less likely to pick up wind noise. Yet, because of its small size it uses very small batteries, which have a shorter life and can be difficult to install and remove. They often lack features, such as volume control or directional microphones. Earwax can clog the speaker.

An in-the-canal (ITC) hearing aid fits partly in the ear canal. Again, it is for mild to moderate hearing loss and is less visible than larger styles. It has many of the same problems as CIC hearing aids.

An in-the-ear (ITE) hearing aid is custom made either with a bowl-shaped area occupying the outer ear (full shell) or one that fills the lower part (half shell). Both are for people with mild to severe hearing loss. They are available with two directional microphones, volume control, longer battery life including rechargeable batteries. Again, earwax may clog the speaker, wind noise may be present, It is more visible but may be easier to handle.

Behind-the-ear (BTE) hearing aids rest behind the ear. A tube connects the hearing aid to a custom earpiece = ear mold that fits into the ear canal. This is the generic style appropriate for everyone, with any hearing condition. Since this is the largest type of hearing aid, it can fit in more electronics and batteries, has directional microphones, increases amplification, picks up more wind noise, and typically uses rechargeable batteries.

Receiver-in-canal (RIC) and receiver-in-the-ear (RITE) are similar to BTE hearing aids, but with the speaker = receiver in the ear canal, connected to the hearing aid with wire.

People with better low-frequency hearing and mild to moderate high-frequency hearing loss may want to use an open-fit hearing aid with an open dome in the ear.

People with hearing disabilities should think through the capabilities they want before deciding on a style. While younger people, especially, may want their hearing aids to be invisible, smallness introduces limitations. Growing one’s hair longer may be a better approach to concealing hearing aids.

Features to consider

Some features may improve one’s ability to hear in specific situations. All hearing aids have some amount of noise reduction available. The amount of noise reduction varies. Some also offer wind noise reduction.

Directional microphones are aligned on the hearing aid to provide for improved pickup of sounds coming from the front, and with reduced sounds from behind or from the side. These are particularly useful in a noisy environment.

Rechargeable batteries can make life easier by allowing batteries to be charged, rather than replaced.

Telecoils make it easier to hear when talking on a telecoil-compatible telephone or listening in an environment served with an induction hearing loop.

Another approach is wireless Bluetooth connectivity, achieved by pairing hearing aids with cellphones, music players, computers and televisions. Sometimes an intermediary device = a streamer is used to pick up the signal and send it to the hearing aids.

Some hearing aids are equipped with a remote control, that adjust features without hearing aid contact. Increasingly, a cellphone app is used for this.

Direct audio input allows audio from a television, computer or a music device to be attached, with a cord.

Some hearing aids can store several preprogrammed settings for various listening needs and environments. Trish has four settings on her hearing aids: normal, restaurant, hearing loop and silence.

Since most people use two hearing aids, these can be synchronized = function together so that adjustments made to one hearing aid will also apply to the other aid, simplifying control.

It takes time to adjust to a hearing aid. There is evidence showing that listening skills improve gradually as one become accustomed to using amplification. One’s own voice sounds different when wearing a hearing aid.


Currently, I am spending considerable time daily to understand hearing and hearing loss. My aim is to provide people in my immediate family (possibly extending outwards to friends) with better advice than they can obtain from profit motivated hearing professionals.

Modern hearing aids have to be configured to match the hearing loss, physical features, and life situation of the user. The starting point is an audiogram. So one of my first goals is to be able to produce these. My next goal is to be able to fit a hearing aid, so I am also learning more in general about audiology and audioprosthology.

The reason for this is that my potential first client is dissatisfied with the fitting and other services she has received from professionals. I have no intentions of working with anything other than digital hearing aids. Thus, I will not be working with anything resembling an osseointegrated auditory prosthesis = bone-anchored hearing aid or cochlear implant.

I am particularly interested in hearing other people’s experiences with hearing assistance. Those who want, can post a comment. Those who prefer to remain anonymous, can send me an email.

Sensory Impairment

This weblog post looks at impairments related to the senses, hearing and seeing, in particular. It is targeted at older (60+) readers. Younger people are more adaptive when it comes to using technology to reduce the consequences of their impairments. They quickly master technological innovations. Many will receive systematic, professional follow-up and assistance throughout their lives. Those with serious hearing impairments learn sign language and to lip-read. Those with serious visual impairments, especially the blind, learn Braille, and attend special classes. Both groups will have professional help to choose technology that will make their impairments less debilitating. Such is not always the case with people who develop impairments later in life.

Technological overload is a very real problem for older people, even those living without an obvious impairment. There may be several different ways in which such a situation can be improved using technology, but older people with an impairment frequently lack the (cognitive) ability and/ or will to use them all. There are too many choices. The key, then, is to select the one or two different technologies that will maximize their return on time invested.

Web accessibility is increasingly important. It involves making the use of the internet, and the World Wide Web in particular, easier. The World Wide Web’s (w3.org) Web Accessibility Initiative (WAI) provides not only resources but also web content accessibility guidelines and checklists. Here are links to some of the resources. The resources section is a good place to start. This can be followed up by consulting these resources: Strategies, standards, resources to make the Web accessible to people with disabilities; Web Content Accessibility Guidelines 2.0; Web Content Accessibility Guidelines 2.0 quick reference.


One major aid to sight impairment, is the use of eyeglasses. These are typically made to correct the specific imperfections of each user’s eyeballs. Glasses are made specifically for screen usage. This blogger used such a pair for several years. They do ease eye strain and the unnatural head contortions that result from using progressive lenses. Currently, the use of a large (27″) screen, appropriately positioned, is now allowing this blogger to avoid having to wear glasses at all.

As an aside, people wanting to make their own eyeglasses, from scratch, may want to consult this YouTube video. Those preferring to make just the frames would benefit more from this YouTube video. Otherwise, this topic will not be developed further, except to say that the French-Italian vertically integrated EssilorLuxottica Group, has been allowed to develop a near-monopoly when it comes to eye-care products.

Background lighting is another important consideration, when using a computer. General information about lighting has been presented in another weblog post written in 2018. Similarly, some of the factors that should be taken into consideration, regarding displays/ monitors/ screens/ televisions has been discussed more recently in yet another weblog post in this series, Media Player.

In terms of computers and hand-held devices, all (?) operating systems provide assistive features. For visual impairments these include switches to allow high contrast backgrounds, large text, and a screen reader. Usually, there are individual controls that allow each of these to be tweaked.

Many older users are unaware that their computers are equipped with a mechanism that will read screen content, and even allow voice commands . In Windows the reader is called Narrator, while the voice commands are part of Speach Recognition, which can be set up to use a microphone for system input.

Apple has an even more sophisticated product, VoiceOver, that is more than a screen reader. It is used on both MacOS and iOS products. It also provide status information (such as battery level) as well as information related to a specific app being used. Voice Control (and not Siri) is Apple’s equivalent program for voice control.

On Android systems the screen reader is an open-source app called TalkBack. However, it also appears under other names, including: Screen Reader, Voice Assistant, SoundBack and KickBack. Voice Access is the Android app for controlling a device with spoken commands.

Speakup is a screen reader for Linux. It allows users to interact with applications and the OS with audible feedback from the console using a speech synthesizer and to navigate around the screen. As usual for Linux, there are multiple programs for speach control. Those interested in this topic are directed to this introductory Wikipedia article.

There be other reasons than vision impairment, including dyslexia, that may require a person to use speech synthesis for text-to-speech (TTS) purposes. For example, an e-book/ e-mail/ web-page can be read to a person doing a menial task (or anything else that provides a cognitive surplus) on a handheld-device (hopefully in a pocket). It is left as an exercise for interested readers to find a suitable app for their purposes and equipment. This wikipedia article, may provide some hints.


For those people who have a hearing impairment that does not require the use of a hearing aid, or choose not to use one, one way to improve hearing is to use over the ear headphones. Recently, this blogger acquired a Logitech G Pro X headset. It comes with several cables and adaptors that allow it to be used with hand-held devices, such as a smartphone, as well as laptop/ desktop devices with assorted characteristics.

One of the first challenges is to keep and maintain order. This means that the headset as well as the cables and adaptors have to have specific locations where they are stored when not in use.

The relevance of the remainder of this webblog post assumes that the hearing impaired person is equipped with a hearing aid, and that it improves their ability to hear in real-life, physical situations such as conversations involving one to a few other people, or other situations such as a store checkout where there can be background noise.

A hearing aid is equipped with a microphone, an amplifier that increases the sound pressure, and a speaker. When the hearing aid is initially set up, or adjusted, the various frequency areas receive differing degrees of amplification.

In addition, many hearing aids contain a telecoil (t-coil) To use an induction hearing loop or the t-coil function on smart phones, a t-coil must be present and activated on the hearing aid.

A t-coil, is a small copper coil in a hearing aid that acts as a wireless antenna that links to a sound system or PA system, delivering customized sound to the hearing aid wearer. It is an option on most hearing aids and is generally in all cochlear implant processors.

Originally used to hear better on the telephone, the t-coil is necessary to hear within a loop system. Just increasing the volume on a hearing aid or cochlear implant doesn’t necessarily improve the clarity. That is the “wow” factor of a t-coil in a hearing loop system. The clarity and understanding is unequaled when listening in a loop.

With a t-coil installed in the hearing aid, the user simply pushes the button or switch for the “T” setting – no additional headsets or receivers are necessary to hear clearly in the induction loop or on the telephone.

The loop system consists of a microphone to pick up the sound (e.g. spoken words) and an amplifier which processes the signal, which is then sent to a loop cable. A loop cable is a fixed wire that is placed around the perimeter of a specific area. This area can be quite large, e.g. a theatre or a church, or quite small, a person’s living room for example or even down to a chair. A loop can even be fitted around the person’s own head (neck loop). The wire then sends the signal directly to the hearing aids of those who are in the room when their hearing aids are set in T-mode.

The telecoil in a hearing aid (also called t-switch or t-coil) is a tiny coil of wire around a core that will induce an electric current in the coil when it is in the presence of an activated loop system. Normally, a hearing aid picks up sound with a microphone and then amplifies the sound. With a telecoil, the hearing aid “hears” the magnetic signal from the loop system and then amplifies that signal.

Media Player

This television set made by Tandberg in Oslo, using the Radionett brand, is a Grand TV kabinett, from 1961. The CRT screen is bowed, as was typrical for the time. The varnished wooden cabinet is mounted on removable legs with white plastic wheels. It features stereo speakers, one on each side. Brass is used decoratively on the feet and around the screen. There are white plastic buttons under the screen, and black knobs on the side, to control the machine. “This is the TV model in greatest demand, with a 23″ large picture tubes, and two large concert speakers”, according to a Tandberg ad from 1961. This machine is in the collection of the Stiklestad National Cultural Center, in Verdal, a neighbouring municipality to Inderøy.

In 2020, a media player is a redundant piece of equipment – if one has a appropriate network attached storage (NAS) server, the topic of next week’s post. Yet, it is its own separate topic because of three different, but related, challenges.

First, people do not understand humankind’s physical capabilities and limitations when it comes to normal seeing and hearing. Normal is the operative term here. Visual impairment will be discussed in its own weblog post: 2020-11-24. Hearing impairment will be the topic one week later: 2020-12-01.

Second, this limited understanding results in the purchase of peripherals, such as speakers and screens, that don’t match user needs. On top of this they will purchase media players or a NAS that are neither suitable nor likeable, from hardware/ software/ operational perspectives.

Third, people tend to make evolutionary, rather than revolutionary, purchasing decisions. They replace components, rather than rethinking the components they need. For example, they may be used to having a television set with an attached recorder for watching video and the accompanying audio content. At the same time, they will have a separate stereo system for reproducing music. Unfortunately, such thinking belongs back in the twentieth century, not the current century that is already more than 20% over.

When we (along with the rest of our local community) updated to broadband, effectively at the beginning of 2019, a number of cable television options were available as a package for about NOK 1 500 a month, with an internet speed of 500 Mbits/s. We declined to have this, and opted for a 50 Mbit/s speed, without cable television, for NOK 600 a month.

A main purpose of a media player is to take content either from an online-source or from a file stored somewhere, including personal handheld devices aka mobile phones, and to send the video content to some form of display/ projector, and the audio content to some form of loudspeaker/ headset. Handheld devices, can be used to control the media player. In essence, they are the 21st century’s remote control.

If people use a particular processor or operating system on their laptop or desktop machine, they will often want to use the same one on their media player. This is understandable, for it keeps them in their comfort zone.

Unfortunately, there are still hardware issues with respect to Intel processors, and – to a lesser degree – those of Advanced Micro Devices (AMD). This design flaw has been known since the beginning of 2018. People are encouraged to use ARM or AMD, rather than Intel processors where these are available. Apple, has recently abandoned Intel and gone over to ARM.

An aside: In 1990 ARM stood for Advanced RISC Machines, a company that started life in 1983 as Acorn RISC Machine, referring to the processor in the Acorn Archimedes computer, used by many schools. From 1998 ARM is simply Arm, not an abbreviation for anything.

Yet, for example, Windows users will often complain about the bloatware on Windows 10, but not do anything about it, either on their personal computer, or a media player. More specifically, they will seldom explore open-source software, including operating systems, as an alternative to the commercial products on offer.

At Cliff Cottage on 2019-04-11, an Asus PN 40 computer was ordered to replace an Asus Tinkerboard, similar to a Raspberry Pi (RPi), as a media player. It is equipped with an Intel Celeron processor, effectively demonstrating that I don’t follow my own advice. The hardware on the PN 40 is more than adequate for its role as a media player. It includes: a Western Digital Green 3D Nand M.2 2280 triple-level cell (TLC) solid-state drive (SSD) providing 240 GB; and, 2 x 4 = 8 GB matched Corsair Vengeance SO DD4 2400 MHz, CL16, 1.2 V DC, non-buffered, non-EEC RAM cards.

The device is low-powered and fanless, but capable of playing videos and music stored on Mothership, the family Network Attached Storage (NAS) server. It is equipped with a LibreELEC = Libre Embedded Linux Entertainment Center, operating system, described as “just enough Linux for Kodi“, an open-source media player, which is also installed.

If the purchase of a media player had been delayed to now (2020-10) it would have been an Asus PN 50, a similar, low power (read: minimal watts), yet a machine with adequate processing throughput. It would be equipped with an AMD Ryzen 3 processor. At the time of purchase, these were not available in Norway. Cliff Cottage now has an Asus PN 50 with a Ryzen 7 4700U processor, but it is being used for other tasks.

An even cheaper, but perfectly adequate, media player can be constructed from a RPi 4 B with anywhere from 1 to 8 GB of RAM. Because of its tendency to overheat, cooling must be used. One approach is to place the RPi in a Flirc case.


The human eye is not impressive. For eyes to write home about, examine assorted species of mantis shrimp.

Boomers probably experienced cathode-ray tube black and white televisions in the 1950s with PAL providing 625 lines, and NTSC providing 525 lines, essentially 480i (interlaced). This was then upgraded to colour television in the 1960s.

In the 1990s, flat-screen televisions emerged and now dominate. High definition (HD) = 1920 x 1080 pixel resolution, became a standard with the high definition multimedia interface (HDMI), defined in 2002. A decade later, in 2012, ultra high definition (UHD) = 3840 x 2160, four times the pixel count of HD (hence, 4K) was defined, and in 2020, is now dominant.

Early flat-screen televisions used plasma technology, then came liquid crystal displays (LCD) that needed backlighting. LCD usually refers to the use of cold cathode fluorescent lamps (CCFL) for backlighting. LED screens are LCDs that use light emitting diodes (LED) for backlighting. This technology is actively used today. Organic light emitting diode (OLED) technology uses diodes to generate colour and light, like plasma screens, but they are smaller and thinner than LED-lit panels, and are capable of producing the best black levels available (highest contrast ratios). OLED screens are considerably more expensive than other screens.

A television in 2020 has 4K resolution. HD is out of date, while 8K is not only too expensive, it lacks content. A video refresh rate of 60 Hz is acceptable, 120 Hz is better, while gamers maintain that 144 Hz is best. Yes, this is a real consideration, if one is to avoid having multiple screens in a household. High dynamic range (HDR) refers to a colour standard that provides a more extensive range of colours, greater contrast levels and increased brightness, compared with the colour rendition on standard HD and 4K sets. Some users feel HDR offers more realistic colours. Others disagree, describing them as artificial. Most regard them as an improvement. OLED TVs typically provide better colour rendition than standard LCD sets, but are considerably more expensive. QLED TVs, where Q = Quantum, referring to photo-emissive particles, are a more affordable middle ground. Many reviews state that it is better to have four or more HDMI ports, with one or more in HDMI 2.1 format.

Currently, at Cliff Cottage there is a Samsung 40″ LED HD screen, made in 2010 but purchased used at half the new price (NOK 2 500 vs NOK 5 000) in 2012. We have never used more than two HDMI inputs. One is attached to the media player, the second has an HDMI cable permanently attached, that can be plugged into a laptop. When this screen ceases to function, it is uncertain if it will be replaced with another screen/ monitor. A 4K 55″ television now costs about NOK 5 000. A 4K 65″ is about NOK 7 000.

Projectors vs Screens

One main question is if the quality difference between a screen and a projector outweighs their respective ecological impacts. A large television/ screen/ monitor consumes many kilos of electronic components, that have to be recycled when the novelty/ economic/ physical lifetime of the product is over. My estimate is that a projector weighs < 10% of a television, although I have not undertaken any research to substantiate this claim.

Thus, we will be examining 4K projectors carefully, over the next few years. When our family was living in Molde in 2002-3, we regularly used a projector, borrowed with permission on weekends from the school where we worked. At that time, bulbs were expensive, used a lot of power and had to be replaced regularly. Today, most projectors are either LCD-based, or Digital Light Projection (DLP) based with a laser, LED, or LCOS (liquid crystal on silicon) light source.

If the projector route is taken, a Philips PicoPix Max provides a minimalist solution. It is a wireless native HD projector, running under the Android OS, with a control touchpad on top. Its built-in battery lasts for three hours of projection. It has Wi-Fi, Bluetooth and USB-C connectivity. Its LED projection source should last for 30 000 hours, and project up to a 120″ (3 meter) image. A more expensive alternative is the Aaxatech 4K1 mini-projector, that costs US$ 1 000. It offers 3840 x 2160 (4K) resolution, 1 500 lumens and 30 000 hours of illumination. Another choice is an Xgimi H2 that uses DLP with four channels of LEDs to beam content. Providing 1350 ANSI Lumens of brightness, requires an effective cooling system. This increased light reduces the wash-out of colours and allows daylight viewing. With its own camera, it is able to adjust focus automatically. It also provides auto keystoning. In terms of sound it provides 16 W through two speakers for treble and mid-range, and a diaphragm for the bass. One major problem with many manufacturers is their repeated attempts at vendor lock-in.

Personal comments: 1) For many years, I had hoped that the Gigabyte Brix Projector would evolve into something useful. Currently, it offers a machine with 75 ANSI lumens, which is inadequate for all but the darkest of localities. 2) The use of a projector like the Xgimi H2 will probably mean that the Asus PN 40 can be repurposed, as the projector is its own media player.


The human audible frequency range stretches from about 20 Hz to 20 000 Hz (20 kHz). The (Harry) Nyquist (1889 – 1976) – (Claude Elwood) Shannon (1916 – 2001) sampling theorem states that sampling must exceed twice the maximum frequency. This means that the rate has to be 40 kHz or more.

In practice, two sampling rates are used. The first, 44.1 kHz used on compact disks (CD) was inherited from pulse code modulation (PCM) adaptors used to transfer data from recording studio tape to CDs, with a sampling depth of 16 bits/ sample. This capability was developed by Philips and Sony, starting in the 1970s. The second, the digital audio tape (DAT) format of 1987, uses a sampling rate of 48 kHz, which is the standard for professional audio.

The HDMI TV standard (2003) allows both 44.1 kHz and 48 kHz standards, although DVD-Video and Blu-ray Discs use only 48 kHz. Most PC sound cards contain a digital-to-analog converter capable of operating native at either 44.1 kHz or 48 kHz. The average human has no need to exceed these capabilities.

Sound reproduction

There are two major ways of getting sound into the ears of listeners: loudspeakers and headsets. The main advantage of loudspeakers is that they distributes sound to multiple people throughout a venue/ house/ room. This is precisely its main disadvantage. There are numerous types and quantities of loudspeaker systems available. Flat-screen displays often come with built-in speakers that are too thin to give a dynamic range people want. Thus, it is common to augment/ replace these speakers with soundbars, mounted either above or, more typically, below the display, to improve acoustics. They are easy to set up, and are usually less expensive than other stereo sound systems. Some soundbars have left, center, and right speakers plus detachable rear-left and rear-right speakers, and a sub-woofer, to provide surround sound. Premium soundbars come equipped with equalizers, which allow the sound to be tuned to compensate for the shortcomings of room dynamics. Despite these augmentations, some people are critical of their small size and/ or position, and opt to use speakers placed throughout the space.

The main advantage of headsets (earphones/ earbuds) is that sound can be individually adapted for each listener. At the same time, people who are not interested in listening to something can avoid it. Perhaps the greatest disadvantage is that every person must have their own headset. Headsets can be wired or wireless. The main advantage of wireless systems is that they allow a person greater mobility. The main disadvantage is their cost.

Appendix: HD vs 4K Displays

Guidelines from the Society of Motion Picture & Television Engineers recommend viewing at a distance where the screen fills up about 30° of the field of vision. Unfortunately, this recommendation does not take screen resolution into account. If one sits too close to a screen, the individual pixels become visible, detracting from the viewing experience. This is also dependent on the size of the pixels. With HD (1920 x 1080), a given size screen requires a person to sit further back, because it is the pixel size that has to be optimized. With UHD/ 4K (3840 x 2160), it is the field of vision that has to be optimized. .

Type/ limiting factor40″45″55″65″
HD/ pixel size1.561.742.142.50
4K/ field of vision0.710.800.981.25
Optimal viewing distance in meters proposed by Rtings

People are creatures of habit. If they are used to one particular viewing position, they will try to keep that constant, preferring to change the size of the screen, rather than moving closer. This means that consumers are often willing to spend more money to buy a larger screen that optimizes their field of vision, when pixel size issues are resolved.

Other considerations include refresh rates which should be 60 Hz for most activities, although gamers prefer 144 Hz. There is no need for anything beyond this. Note: HDMI 2.0 is needed for 4K video at 60 Hz with 24 bit/px colour depth.