What is the Difference between an Amplifier and Pre-amplifier?

What is the Difference between an Amplifier and Pre-amplifier?


DPA-90B Mixer Amplifier

DPA-90B Mixer Amplifier

Audio amplifiers are found in home stereos and hifi systems as well as in commercial audio systems like PA systems, recording studios and club DJ sound systems. Television also makes use of different types of amplifiers which are integrated with the antenna. Signal boosters are also available for cellphone networks for both home use and commercial installations. In audio systems, the amplifier is used to boost the input audio signal from different sources such as studio recordings (instrument, equalizer, mixer, sound effects, tone and vocal inputs), microphone, turntables, record, CD, cassette and digital audio players.

The audio amplifier increases the amplitude of the input sound waves, thereby giving the signals enough strength to energize or activate the speakers. Amplified sound waves have more life and intensity in them which allows them to be perceptible, heard clearly and enjoyed by the listener. Think of amplified signals as food with seasoning or bread with butter spread. Seasoning and spread enhances the taste, otherwise you wouldn’t enjoy the food.

Input signals are weak due to distortion, dispersion and relatively low energy levels. In Physics, the energy of a wave (K) depends on its amplitude and frequency according to the formula K=1/4(µA²w²λ), where A=amplitude, w=angular frequency, λ=wavelength and µ=constant linear density.

The proportional relationship between the Energy (K) and Amplitude (A) is shown below:

K ~ A²

The proportional relationship between the Energy (K) and Angular Frequency (w) is shown below:

K ~ w²

Amplifiers make use of this relationship to increase the energy of a sound wave. That is increasing its amplitude.

The wave energy can also be expressed in terms of power (P), which is the rate of transfer of energy:

P = ½*µ*w²*A²*v, where µ = constant linear density, w = angular frequency, A = amplitude, and v= wave propagation velocity.

Basically, a low-energy wave has a smaller amplitude, whereas a high-energy wave has a higher amplitude. The former is weaker and quieter whereas the later is stronger and louder.

So what is the difference between a Preamp and Amplifier?

Think of a preamp as a weak signal booster and the amp as an enhancer, refiner and producer of high quality sound.

A lot of audio amplifiers in the market have a two-stage signal processing system consisting of pre-amplifier and amplifier. These two components are inbuilt within the device, so you won’t need a separate pre-amplifier. The pre-amplifier is highly sensitive, designed to pick up weak audio signals from a microphone. It amplifies the microphone audio input by as much as 1000 times, bringing the audio to line-levels which can then be transmitted to the final or end amplifier which boosts the signals further, enhancing them for speaker reception and activation as well as audio appeal for listeners.

In recording studios, PA systems and other high level commercial systems, pre-amplifiers are rarely used because mixers can perform the pre-amplification role quite well. Standalone preamplifiers are another option if your amplifier doesn’t have one integrated, but it’s very to find these in use or being sold in the market. The advantage of a separate preamplifier is that it is free from the amplifier, therefore it is not affected by internal noise caused by the power amplifier. However, the disadvantage of a separate device is the matching difficulties and compatibility issues between the two connections, making it difficult to achieve the required synergy for optimum performance.

Some home stereo and hi-fi systems including TV have inbuilt amplifiers which power the speakers. However, standalone amplifiers can be purchased and connected to the speakers. It’s very important to know that a weak signal from a microphone and other inputs (e.g. turntable, record, CD, cassette or digital player) will be amplified by a different amount depending on the type of amplifier. Class A amplifiers are the best and commercial systems will produce more powerful outputs than home systems. There is a huge different between a club and home stereo amp. The former is more powerful.

What is more powerful, woofer or subwoofer? What does it do?

What is more powerful, woofer or subwoofer? What does it do?

Klipsch R-120SW Black Subwoofer

Klipsch R-120SW Black Subwoofer

Normal modern speakers that are manufactured today come with at least 2 drivers, the woofer and tweeter. The woofer produces bass (low frequency sounds) and the tweeter produces high frequency sounds (high-pitched sounds). This is the minimum standard in the hi-fi/stereo production industry, but computer speakers have the fewest features of them all, a single speaker with a port/vent, which you may call a 1-way speaker. Before we discuss the difference between a woofer and subwoofer, it’s important to understand the factors contributing to the efficiency of a speaker, and thus how much bass (low frequency ranges) it can produce. Basically, the lower the frequency, the deeper and richer the bass. Super bass systems are below 80Hz. Professional bass systems are below 100Hz and home consumer systems are below 200Hz. Most subwoofers (both commercial and consumer) have a minimum frequency rating of 20 or 25Hz. The maximum can be anywhere in an acceptable range depending on the manufacturer’s specifications, but anything that exceeds 200Hz going over 300Hz is not bass. You are approaching mid-range frequency.

The efficiency of a speaker at low frequency ranges is defined by Thiele/Small parameters, whereby:

ᵑ₀ = (4₀∏² F3 Vas)/ (c3 Qes) * 100%

ᵑ₀ = Acoustic reference efficiency

F3 = Resonant frequency of the speaker. Frequency at which the mass of the speaker (cone and voice coil) will start to vibrate naturally at its highest amplitude, causing it to shatter or break. It can also be described as the frequency at which the sound/acoustic frequency is equal to the natural frequency of the speaker or vibrating mass. The speaker will be unable to generate sound from the input signal as it approaches this point.

Vas = Equivalent internal volume of the speaker box in litres needed for compliance for a given speaker size/cone diameter (determinant of optimum box size).

Qes = Electrical damping or Amount of control from the speaker’s electrical suspension system (Voice coil and magnet)

C or Cas = Acoustic compliance of the speaker’s suspension.

What this equation tells you is that the efficiency of a speaker is directly related proportional to its Vas parameter, that is its cone diameter and optimum box volume.

Efficiency ~ Vas

E ~ Vas

The efficiency is also directly proportional to the resonant frequency F3 (F to the power 3)

Efficiency ~ F3

E ~ F3

But this is an exponential equation, we need to find out what F is proportional is to:

E = F3

Re-arranging the equation >>

F3 = E

Finding F by re-writing the equation >>

F = E

We can see that F is proportional to E

This means when we decrease the frequency further (extend the range in the lower end of the spectrum), the efficiency of the speaker will be reduced.


As seen in the above formulas and relationships, the size of the speaker matters. Generally for shopping purposes, the bass power of a speaker is represented by its cone diameter, this also applies to a subwoofer and woofer. The bigger the diameter of your subwoofer, the deeper the bass. Hi-fi/stereo Subwoofer speakers range from 20cm to 53cm in diameter, but they can exceed this size, a maximum size of 152cm has been made. Computers and small home theatres make use of smaller 10cm diameter subwoofers.

What Does a Subwoofer Do?

Previously, we noted that bass systems are in the low frequency ranges, and that 300Hz and below is where bass lies. The human hearing range is 20Hz to 20,000Hz. Anything outside this range is inaudible to the human ear, so the minimum low-frequency (deepest bass) you can hear is 20Hz.

We also said 2-way driver speakers are the most common standard in the Hi-fi and stereo market. Of course, we also have a lot of 3-way drivers and higher. Tower speakers can accommodate a lot of drivers. A 2-way speaker has a woofer and tweeter for low and high frequency ranges respectively, whereas a 3-way speaker has woofer, mid-range speaker and tweeter for low, medium and high frequency ranges respectively. A 4-way speaker has a woofer, squawker, tweeter and super-tweeter for low, medium, high and extremely high frequency ranges in order.

As you can see, a woofer is included in every modern speaker to cater for bass, but the question that you must ask as a Hi-fi/stereo consumer is what is the frequency rating of the speaker. All speakers have a frequency rating shown on the device as well as in the manufacturer’s specifications manual. Just to give you an example, here are screenshots of the frequency range of some speakers on sale:

LS50 Meta 2-way reflex bass speaker

Frequency range: 47Hz to 45KHz (45,000Hz)

XTRIKE-ME 2.0 stereo speaker with RGB backlight

XTRIKE-ME 2.0 stereo speaker with RGB backlight

XTRIKE-ME 2.0 stereo speaker with RGB backlight

Frequency range: 160Hz to 20KHz (20,000Hz)

BRAND 2x6.5 inch Big Power Wireless Party Speaker

BRAND 2×6.5 inch Big Power Wireless Party Speaker

BRAND 2×6.5 inch Big Power Wireless Party Speaker

Frequency range: 90Hz to 20KHz (20,000Hz)

2.0CH BT5.0 Hi-fi Bookshelf Studio Speakers

2.0CH BT5.0 Hi-fi Bookshelf Studio Speakers

2.0CH BT5.0 Hi-fi Bookshelf Studio Speakers

Frequency range: 60Hz to 20KHz (20,000Hz)

2.0 Bluetooth Computer Speaker

2.0 Bluetooth Computer Speaker

2.0 Bluetooth Computer Speaker

Frequency range: 200Hz to 20KHz (20,000Hz)

Audioengine A5+ Speakers

Audioengine A5+ Speakers

Audioengine A5+ Speakers

Frequency range: 50Hz to 22KHz (22,000Hz)

Crosley S100A-BK Bluetooth 2-Way Stereo Speakers

Crosley S100A-BK Bluetooth 2-Way Stereo Speakers

Crosley S100A-BK Bluetooth 2-Way Stereo Speakers

Frequency range: 50Hz to 20KHz (20,000Hz)

If you noticed above, a speaker like XTRIKE-ME 2.0 only supports the upper band of the bass frequency range. It doesn’t go lower than 160Hz, whereas a speaker like LS50 Meta  covers a wider bass frequency range, going as low as 47Hz. This is a speaker you would like to buy if you are interested in a deeper bass. The lower the minimum the better.

A speaker like XTRIKE-ME 2.0 is fine if you don’t care about a richer/deeper bass. What if you bought this speaker and you want to improve its bass? This is where a subwoofer comes in. In this case, you must get a subwoofer that will go deeper than 160Hz to your preferred minimum for example 50Hz. Subwoofers can go deeper than 50Hz, down to a minimum of 25Hz or 20Hz which is the lower threshold of hearing.

How Does a Subwoofer Get to this Lowest Hz?

What Hz is required to increase bass? The answer lies in the previous formulas we discussed about the efficiency of a speaker. The bigger the size of the speaker (cone diameter), the better the bass. As you have realized, subwoofers often come as standalone speakers because they are too big to be integrated in compact speakers such as bookshelves. There is an economic limit at which the size of a speaker can be. It cannot be too big for packaging and transportation as this will drive up costs. Consumers also expect products that won’t take up too much space or stick out like a sore thumb. That’s the reason why most stereo speakers don’t have a built-in subwoofer as it takes up too much space.

To fire up the bass in your stereo, you have to connect it to a subwoofer. A subwoofer is often larger than your stereo, which shows you how much of bass power it packs. There are two types of subwoofers, the passive and active subwoofer. The former is powered by an external amplifier and the later is powered by an inbuilt amplifier. Active subwoofers have a more powerful and deeper bass.

At this point, if you have read through the article, you should know that a subwoofer is an optional/standalone item that is more powerful than the woofer on your 2 or 3-way stereo speaker.

When you are shopping for stereos and hi-fi systems, it’s important to know you have the following options:

  1. Buying a stereo speaker (e.g. bookshelf speaker). These are not sold with a subwoofer, you have to find one for yourself if you need it.
  2. Buying a hi-fi system with stereo speakers.
  3. Buying a hi-fi system with stereo speakers and subwoofer.


Are Bookshelf Speakers Worth It? Do They Have Good Bass?

Are Bookshelf Speakers Worth It? Do They Have Good Bass?

Bower and Wilkins 685-S2 Bookshelf Speakers Premium White Satin Finish

Bower and Wilkins 685-S2 Bookshelf Speakers Premium White Satin Finish

Bookshelf speakers are worth it if you are not entertaining a crowd (small, medium or large audience). They are not suitable for entertainment of commercial proportions, for example clubs, home parties and outdoor events. What defines a bookshelf speaker is its compact size which can fit in well inside your room without stealing the limelight, standing out or taking a lot of space. It’s made to fit in aesthetically and harmoniously with your furniture without grabbing attention. Another main feature of this speaker is its fully-detached speaker cabinet which can be placed anywhere in your room. This speaker is placed on top of furniture such as shelves, tables, desks, drawers, cupboards and stands. It can also fit inside an open-face compartment.

A bookshelf-speaker is worth it if you have a small room, which allows to enjoy its near-field performance and reach. If you have a large room, it should be strategically placed near your sitting position in the corner. Two speakers can be arranged in an equilateral triangular setting with their front face facing the focal point (the listener) and at an angle of 60 degrees from the base. This position ensures an optimum dispersion of sound waves in the listener’s direction.

Do Bookshelf Speakers Have Good Bass?

Whereas towers are the most powerful speakers that you can have in your room, bookshelves will not give you the best bass. If you are interested in powerful bass and wide frequency ranges, go for tower speakers. That is not to say bookshelves have the weakest bass, far from it. They can deliver appreciable bass depending on the manufacturer’s specifications. Not all bookshelves are alike. They are made of different materials and systems, coming in different sizes, frequency ranges, methods of connection and weight.

The cheapest bookshelf speaker you can have is the external computer speaker which has a bass-reflex port or 2-way drivers. Hifi speakers are more powerful than computer speakers. Among Hifi speakers, there are 2-way drivers with a woofer and tweeter, and the more powerful 3-way drivers with a woofer, mid-range speaker and tweeter. 3-way drivers are more expensive as well, and these are the type of bookshelf-speakers that will give you good bass. Size matters as well, the bigger the size of woofers, the better bass it will produce. Bigger woofers have high tolerance limits and can handle high sound pressure levels (SPL), although they use more electrical power and need higher voltages than smaller speakers.

A lot of modern bookshelves are available as 2-way drivers, and the premium quality are often 3-way drivers. Examples of 3-way driver bookshelves include the Yamaha NS-5000 retailing for $14,996, McIntosh XR50 retailing for $8,990, KEF-R3 Model retailing for $2,200 and ELAC Navis ARB-513 retailing for $2,700. On the cheaper end is the Sony Model SSCS5 retailing for $170, Yamaha Model NS-6490 retailing for $140 and Yamaha Model NS-6490 retailing for $130.

If you are budget-conscious, the lower-end 3-way driver bookshelves will be a good choice, but remember that these are smaller in size and will not give you the best bass. A bigger 2-way speaker might do a better job than a smaller 3-way speaker. Premium two-way drivers are not as costly as three-way drivers. The most expensive 2-way bookshelf is around $1,500, which is way lower than a premium 3-way bookshelf starting at $2,200 and going as high as $15,000. Once again, size will make a big difference as well as the type of materials used.

What’s the Difference between Studio Monitors and Bookshelf Speakers

What’s the Difference between Studio Monitors and Bookshelf Speakers

Pioneer DJ DM-40BT Studio Monitor

Pioneer DJ DM-40BT Studio Monitor

Studio monitors also known as monitor speakers are quite different from bookshelf speakers in that the former is used for audio/music production in recording studios to generate clean/natural audio without effects, distortions, alterations or manipulations, whereas the later are for home entertainment purposes. The source audio in consumer entertainment speakers such as the bookshelf speaker comes out in manipulated form to enhance the listening experience and enjoyment of music. Monitors are the opposite, they are not made to enhance or boost the audio, but to filter out all the environmental effects and influences which may alter the source audio. They are designed to give you the raw output which is close as possible to the raw input. At this point, one may be wondering what type of environmental influences will affect raw audio.

Environmental Influences on Raw Audio.

Raw audio, that is natural audio in its clean, unpolluted state is affected and distorted by many external and internal factors which are listed below:

  1. Colouration
  2. Reverberations
  3. Background Noise
  4. Total Harmonic Distortion (THD)
  5. Intermodulation Distortion (IMD)
  6. Transient Intermodulation Distortion (TIM)
  7. External Noise
  8. Internal Noise
  9. Acoustic Feedback Oscillations
  10. Amplitude Distortion (THD and IMD)
  11. Spectral/Frequency Distortion
  12. Phase Distortion
  13. Transient Distortion
  14. Crossover Distortion
  15. Frequency Modulation (FM) Distortion
  16. Saturation Distortion (Non-linear /Overload/Amplitude Distortion)
  17. Distortion caused by low-level inputs.
  18. Distortion caused by high-level inputs.

Excluding external influences which may be filtered out, all audio systems including monitor speakers will have some amount of internal distortion. This distortion cannot be completely eliminated due to the need of some form of transmission and equipment to convey audio signals.

Monitors will minimize distortions where possible, for example, they will produce flat frequency responses (near-flat curves) on a frequency/amplitude graph. Imagine a graph paper with X and Y axis. Frequency is plotted on the X-axis and Amplitude is plotted on the Y-axis. An ideal flat frequency response has a linear graph (straight line) whereas an undulating frequency has a wavy graph with shorter wavelengths.

Colouration is another phenomenon that is handled by monitors. It’s whereby the audio causes the speaker components to vibrate during and after transmission. This vibration distorts the audio quality and therefore it must be measured and minimized.

The monitor speaker used for studio recording is made of high quality materials which are resistant to fracture and damage caused by sudden bursts of signals, high volumes and physical accidents which may take place in the studio while rehearsing and mixing.

The monitor alone will not handle everything that is required to produce unpolluted audio. The studio or room in which the speakers are located must meet specific minimum acoustic standards. These speakers should be used in a professionally-built studio with an ideal environment for filtering out undesired noise and sounds. Studio design should entail acoustic control and soundproofing of the interior – the walls, floors and ceilings. The environment must eliminate or reduce reverberation, absorb sounds, incorporate reflection-free zones, QRD diffusers, hanging bass absorber and so on. But the shape, size and configuration of your room in relation to other elements in room is even more important, as well as the type of materials used and positioning of the monitors.

A lot of modern monitors have inbuilt amplifiers, and they also have two or more drivers for low and high frequency responses. Monitors with inbuilt amplifiers are called “active monitors” whereas those which are connected to external amplifiers are called “passive monitors”. A passive monitor speaker does an excellent job of processing audio /vocal input in its raw/pure state without conversion or distortion. However, the audio input is often weak and you need an amplifier to magnify the signal.

It’s important to distinguish the function of amplifiers in monitors and bookshelf speakers. Their function is not the same. Monitor amplifiers are designed to give life to weak audio inputs without enhancements whereas bookshelf speakers are designed to provide and enhance the audio appeal to music consumers.

A bookshelf speaker is made for convenient and comfortable placement on a shelf, table, desk or compartment. It fits well on top of furniture, saving space and giving you room for other items such as stationery, flower vases, laptop, mouse pad, cups and books.

Modern bookshelf speakers can have two or more drivers for wide frequency ranges. They come in various types such as wired, Bluetooth, single, pairs or satellites. They can be placed on stands as well. The advantage of a bookshelf speaker is its compact body or cabinet which is shorter than a tower speaker in vertical dimensions. These speakers come in various sizes from small to large.

Last but not least, bookshelf speakers or any other consumer speakers cannot be used as monitors. Monitors are not designed for audio appeal, they are made for raw music production, so if you are looking for entertainment or audio effects, they will give you the worst audio. Get a monitor if you are recording music and get a bookshelf if you are listening to music for entertainment.

Are Tower Speakers Outdated? Or More Powerful than Ever

Are Tower Speakers Outdated? Or More Powerful than Ever


MartinLogan Statement e2 Twin Tower Speakers Copy

MartinLogan Statement e2 Twin Tower Speakers – 1998 Model

Towers are tall floorstanding speakers with a narrow profile. There is a reason why these speakers may be associated with outdated vintage speakers for some people, but whatever you think, towers aren’t stuck in the 1970s or 80s. They have evolved and improved to much better modern standards, design and performance just like other devices. But let’s go into the past and look at the history of speakers.

Yamaha the Japanese electronics company made its first Natural Sound speaker in 1967, the NS-30 and NS-20. The speaker had a tall rectangular profile with a narrow edge made of brown-stained wood. The company produced their first 3-way speaker in 1972, model NS-690/NS-670 which had a plain wood  box enclosure, tall but with a wider breadth. This model was popular with audiophiles around the world. Two years later they produced a 3-way monitor speaker, the NS-1000M, a model with a beryllium diaphragm (a world-first) enclosed in a black modernistic skin that is synonymous with speakers today. In 1978, Yamaha launched the return of the traditional plain wood speaker cabinet, but this time it was stained with a brown varnish. The NS-451 was an entry-level model incorporating a trademark white cone on its low-frequency driver. The company continued making tall cabinet/box speakers made of wood or wood composites until 2003, with new models produced each 1 to 3 years. Yamaha had produced 16 models from 1967 to 2003. Obviously, they have designed and manufactured many more models since 2003, and what you have to keep in mind is that the tower box speaker commonly known as the “tower” is going nowhere. It is here to stay. It has taken new functional forms, being adopted even for Bluetooth speakers, home theatre systems while its traditional use as a powerful bass-reflex system is still intact in clubs, parties, bars and other crowd functions. A modern floorstanding tower speaker has a much more visually appealing aesthetic design which makes it more attractive than a vintage box. Major electronic hifi companies and retailers are still selling the tower, and it’s doesn’t look like your typical vintage box.

In the USA, MartinLogan is a speaker design/manufacturing installation company specializing in wireless systems, soundbars, subwoofers, architectural and outdoor systems. Their roots can be traced back to the 1970s when the founders Sutherland and Sanders formed a company based on their interest in speakers. In the early days, the challenge in speaker design was producing bass levels and wider ranges. The KLH model 9 and Quad ESL were the only promising and outstanding speakesr which sought to jump this hurdle. The former was too expensive for consumer success and the later was a hit in England.

Sutherland and Sanders presented their first experimental model in 1980. It was a thin tall rectangular aluminium frame with five bars, wires, linked with an amplifier and powered by electricity. The sound was good but the range couldn’t be increased as the prototype blew up on increasing the volume. A series of experiments with high-tech materials solved the arcing problem and later on theoretical solutions led to the design of the CLS transducer (curvilinear line source transducer) which achieved high frequency ranges while preserving sound quality. Their CLS prototype was showcased in 1982 at a consumer electronics exhibition in Chicago. This transducer received a CES Engineering Award and became an instant success. This allowed MartinLogan Corporation to garner the support and input of innovative engineering experts such as  the manufacturers of NASA space shuttle windows and Teflon non-stick cooking pans. The team came up with a patented system comprising a 5,000V transparent diaphragm and stator coating with a maximum charging capacity of 10,000V. The speaker known as the “Monolith”was enclosed in a tall, flat, narrow-edged rectangular wooden panel . Its sound quality was demonstrated in 1983 at a showroom, attracting dealers and creating a demand in the market. Not only was the sound good but its thin minimalistic appearance was aesthetically pleasing as well. By 1985, the Monolith was generating huge sales enough to make a profit. Sales increased by 1000% (10 times as much) in 1988 necessitating the need for expansion and mass production.  As competition grew in the market, MartinLogan turned to home theatres to keep up with consumer trends, producing a center-channel electrostatic speaker and wall surround-channel speakers which were a first of its kind.

The company continued innovating and engineering while producing some of the best visually appealing speakers in the world which contrasted greatly with the box vintage speakers of the day. The home theatres found a place in the market, propelling them to a major brand name in the USA. In 1998, MartinLogan unveiled their huge high-end twin-tower speaker system called the “Statement e2”. The futuristic design of the “Statement e2” deserves an award. It was ahead of its time, you wouldn’t call it a vintage tower if you saw it today. It’s still one of the most good-looking tower speakers out there, blowing away the competition by miles. The Statement e2 consists of two separate towers which includes an 8-bass driver tower. This was one of the most expensive speakers, retailing at $100,000 in 2003, but the model was discontinued in 2006.

Interesting, but what’s the importance of this history? If you follow the timeline of speakers beginning in 1861, you will notice the evolution of speakers from phonographs (base and horn) to more powerful towers such as the Monolith and Statement e2.  The tower represents power. The first electromagnetic speaker making use of electrical amplifiers was manufactured in 1921 by Edison-Tech. It was much better than the horn. The Edison electromagnetic speaker was housed inside a tall wooden cabinet. This was probably the first tower. Traditionally, wood has been used to build speaker cabinets because of its acoustic and mechanical properties, although MDF (medium density fibreboard) is another alternative that can be used. But certain types of wood (e.g. Russian birch plywood) remain the best for professional high-performance speakers.

MartinLogan Monolith Speaker 1983 Model (5)

MartinLogan Monolith Speaker 1983 Model (5)


MartinLogan_Monolith_III_Speakers Lautsprecher

MartinLogan Monolith Speaker 1983 Model (4)

MartinLogan Monolith Speaker 1983 Model (4)


Edison Electromagnetic Cabinet Speaker 1921

First Tower – Edison Electromagnetic Cabinet Speaker 1921

What are the 4 Types of Speakers?

What are the 4 Types of Speakers

Logitech Wired Computer Speakers

Logitech Wired Computer Speakers

A speaker also known as a transducer is an electronic device that converts  audio signals (electromagnetic waves) into sound waves.  Audio signal transmissions are inaudible to the human ear, so they need to be converted to audible sound waves (e.g. speech, music). This is how a speaker works but we have seen many types of speakers in our shops, homes, studios, theatres and entertainment venues which necessitates the need to classify them accordingly. They can be classified according to the frequency range, use, physical shape and size, environmental requirements, home or commercial quality, method of connection, installation, control and quality of output. We can delve deep into these 11 methods of classification, but you would be much better served if we grouped speakers into 4 groups.

The 4 main groups of speakers are: (Home, Commercial, High Quality and Low Quality Sound)

Home Speakers

These are made for your home environment, optimized for indoor listening experience and entertainment. This type of speaker is suited for your living room, bedroom, TV room or entertainment area. Volume outputs are low to moderate levels, although there are systems which can produce high quality sound at high volumes. If you are living in multi-family residential units (e.g. apartments, condos, terraced houses, duplexes and triplexes), you would want to keep your volume levels down as this may upset neighbours and the local municipality codes and ordinances against noise pollution. In this case, low and moderate levels are tolerable whereas loud systems are not welcome.

High volume systems are suitable for sparsely populated low-density areas, for example, if you live in the countryside and other remote areas, single-family homes and lots are far apart from each other, so there is no risk of annoying neighbours with your loud systems.

A lot of speakers fall under the home category, and these include home theatre systems (sound bars, towers, satellites), ceiling, wall, Bluetooth, wireless, smart-speakers, tweeters, squawkers, subwoofers, woofers and computer speakers. Bookshelf-speakers are another common choice of home indoor systems.

Commercial Speakers

These are specialized sound systems which are way more expensive than home entertainment systems. They are commercial quality, often made for recording studios, clubs, bars, stadiums, theatres, cinemas and other public entertainment venues. Other models are made for public announcement systems, for example the speakers you hear in airports, banks, parliament, conferences, sports venues, public transportation and terminals. Broadcasting stations for TV and radio have their own systems as well.  Commercial speakers you might be interested in if you are in the music production industry are monitor speakers. Party and event organizers might be interested in hiring DJ equipment which includes a PA sound system, the same with a church which might want a PA system for sermons. Video conferencing is another field which makes use of sound systems.

Sound is also used to entertain customers in a shop or patients in the waiting room section of a hospital or medical centre. As you can see, there is a wide application of sound systems in the commercial sector.

High Quality Sound

Most speaker reviews out there are misleading. If you read through these reviews, you will find that the writer is pushing a product just to make an affiliate sale on Amazon. What bugs the mind is that the blogger has listed Bluetooth speakers as their top 5 or 10 speakers with the highest quality sound. If you are familiar with sound systems, you should know that wireless/Bluetooth speakers will not give you the best quality. If you want to get the best/most powerful sound from any system, get a wired speaker which makes use of a cable connection. Bluetooth speakers tend to lag and lose audio quality during transmission.

With that said, the best sound you can get from any system is HIFI quality which is delivered in lossless uncompressed quality. FLAC is a type of HIFI audio format which delivers high quality, but MASTER QUALITY AUDIO (MQA) is the highest quality with near-studio flawlessness.

Generally, commercial speakers have higher sound quality than home speakers. This is due to the fact that they are optimized to deliver a clear lossless audio quality at high volume levels. Have you ever tuned your standalone computer speaker to maximum volume? There is a threshold at which it can deliver clear audio quality. If this threshold is passed, you will notice an increase in weird static noise which interferes with the audio quality.

Low Quality Sound

Compressed audio formats like MP3 and AAC have the lowest quality due to the loss of quality during compression. Although they are not comparable to commercial systems, home sound systems are perfectly fine and comfortable for our ears in the home environment as they are made for a low-key situation in a confined space. You do not need a disco machine in your living room to enjoy your music.

A club/cinema sound system is more powerful than your home theatre, Bluetooth, Smart or Bookshelf speaker. Within your home, Towers will prove to be much more powerful than others, although there are Bookshelf models which are equally powerful.

Phonak Hearing Aid Not Charging | Solved

Phonak Hearing Aid Not Charging

How to Charge Your Phonak Marvel Hearing Aids

Audeo M-R and Bolero M-PR

Charging the Audeo M-R and Bolero M-PR

Phonak is an electronic hearing aid device that works with a pre-installed rechargeable battery. Some of their most common products are the Audeo Bolero, Marvel , Virto, Naida, Brio and Paradise models. The device comes in a small portable case that can be closed and opened. The case can fit in your pocket just like a cellphone and it keeps your device safe from contamination by weather elements such as dust, rain, wind and other particles which can interfere with the performance of your device. The case also functions as a charging station and bank.

To charge your Audeo Marvel, do the following:

Your Marvel case has two charging ports for the left and right hearing devices, which are marked with different colours for clear identification.

Take your device and note the colour of its ear-mold. If the ear-mold is red, insert the device in the red charging port. If your ear-mold is blue, insert the device in the blue charging port.

Look at your device, there is a pivot push button which functions as a volume control. Press the bottom end of the button down and hold for 15 seconds. The indicator light will not come on. Put the device in the charger. The indicator light should come on. The light indicates the battery is charging.

behind-the-ear hearing aid

Phonak – charging the behind-the-ear hearing aid

To charge your Audeo M-R and Bolero M-PR device, do the following:

These electronic hearing aids come in a smaller compact case which is also functions as a charging station. The advantage of these models is that the charging procedures are much simpler.

Your Marvel case has two charging ports for the left and right hearing devices, which are marked clearly with different colours for easy identification.

Take your device and note the colour of its ear-mold. If the ear-mold is red, insert the device in the red charging port. If your ear-mold is blue, insert the device in the blue charging port.

Insert the device in the correct charging port. The light indicator will automatically turn on, flashing red, yellow or green light. Green indicates the battery is fully charged. Yellow indicates the battery capacity is mid-level and red is a warning sign for low capacity.

When the device is fully charged, take it out by grabbing and pulling it straight up.

A behind-the-ear hearing aid can also be charged in the same charging station/case. The blue port is for your left device and the red port is for your right device. However, since a behind-the-ear device is usually not colour-marked, you should  insert it in the correct port by making sure the ear-mold is resting in the inner side of the case.

The light indicator should automatically turn on, flashing red, yellow or green when the device is placed in the charging port. Green indicates the battery is fully charged. Yellow indicates the battery capacity is mid-level and red is a warning sign for low capacity.

When the device is fully charged, take it out by grabbing and pulling it straight up.