Category Sound

What is meant by a treble?

            A treble is a tone whose frequency or range is at the higher end of human hearing. In terms of music, it refers to ‘high notes’ or is the highest part in a composition that has three parts.

            The best examples of treble sounds are the tones of guitars, piccolos etc. Both of them are important instruments. They mostly have very high pitched sounds. The frequencies range from 2.048 kHz – 16.384 kHz.

            A treble clef or a G clef is used to notate such high sounding instruments like the violin, guitar, mandolin, flute, oboe, English horn, clarinet, saxophone, horn, and trumpet.

            In sound production, treble control is used to change the volume of treble notes relative to those of the middle and bass frequency ranges.

What is an amplifier?

            An amplifier is a device used to increase or strengthen the power of a signal. They can be seen in audio equipment of all kinds.

            Let’s take the example of a hearing aid. It has a microphone that picks up sounds from all around and converts them to electric signals that constantly changes in strength. Here, an amplifier takes the signals, and boosts it many times before feeding it into the tiny loudspeaker placed inside the ear canal. The sound thus produced is ‘amplified’ before it reaches the person. That means, the duty of the amplifier is to convert a small electric current into a larger one.

     

 

            Depending on their functions, amplifiers can be categorized as weak-signal amplifiers or power amplifiers. The former is designed to deal with exceedingly small input signals. They are used in audio tape players, CD players tec. History notes that the first electronic device that could amplify was the triode vacuum tube, invented by Lee De Forest in 1906.

What is a loudspeaker?

            Loudspeakers are equipments that we all are familiar with it. By definition, a loudspeaker is a tool that converts an electrical signal into sound waves to provide the most faithful reproduction that is feasible for its design. The most widely used type of loudspeaker is the dynamic speaker. The moving coil principle commonly used today in speakers was patented by Edward W. Kellogg and Chester W. Rice in 1924.

            Depending on the range of frequencies, loudspeakers can be divided into four- subwoofers, woofers, mid-range loudspeakers and tweeters.

            

Continue reading “What is a loudspeaker?”

Why is it said that carbon microphones were a turning point in the history of microphones?

            Developed in the 1870s by Englishman David Edward Hughes, carbon microphones were the first reliable form of microphones. They were widely used for many years before being replaced by other types that showed better performance.

            Structurally, a carbon microphone comprises carbon granules within a small container that is covered by a thin metal diaphragm. It requires a battery to cause current flow. By compressing and decompressing the carbon, sound waves change the amount of electric current flowing through the wire. This, in turn, creates electrical waves.

            The biggest disadvantage of carbon microphones was that they had a limited frequency and would not reproduce music effectively.

Which are some common microphones that can find around?

            On the basis of application, microphones can be divided into different types. The three most common ones are – dynamic microphones, condenser microphones and ribbon microphones. Let’s look at them in detail.

            Dynamic microphones are the most common and durable types, well suited for live sound. They work on the principle of electromagnetic induction, but take loud signals to move the coils.

            The next type of microphones is condensers. They use electrically charged capsules that are far more sensitive than moving coils of the dynamic mic.

            There are both large diaphragm condenser mics and small diaphragm condenser mics. The former is best suited for recording vocals, while the latter is great for high frequency instruments like acoustic guitar and cymbals.

            Ribbon microphones use corrugated metal ribbons that vibrate when pushed by air. But today, they are no longer popular. There is also a microphone known as the piezoelectric microphone. It uses a crystal of piezoelectric material to produce sound.

 

Why is it said that a microphone plays a very important role in day to day sound?

            A microphone, popularly called a mic, is a device we are all familiar with. It is in fact a part of our daily life and can be seen in almost all equipment around us. For example, computers, telephones, televisions, transmitters for commercial radio, tape recorders, hearing aids and public address systems for concert halls, all of them uses microphone.

            Technically, a microphone is a device that converts mechanical energy waves or sound into electrical energy waves.

            Let us see how the device works. When we speak, sound waves carry energy toward the microphone. Inside it, there is something called a diaphragm, which moves back and forth when hit by the waves. As a result, the coil attached to the diaphragm too moves back and forth. This results in the production of electric current, which flows out from the mic to an amplifier, or a sound recording device. Subsequently, the voice of the speaker is heard a loud. This is how personal address systems, electric guitars amplifiers etc. work.

What is meant by the term sonomicrometry?

            Sonomicrometry is a technique that makes use of the transmission of ultrasound energy through certain type of crystals and tissues to measure distance.

            It has a variety of applications, including measuring the distance between two fixed points in a soft tissue environment, and, quantifying the function and dynamics of cardiac, skeletal or smooth muscles. Traditionally, this technique has been used to determine cardiac function on large research animals like dogs, sheep, pigs etc. It was first done by Dean Franklin in 1956, and was quickly adopted by other biologists.

            At present, sonomicrometry is the most prevalent method to determine muscle length changes during animal locomotion, feeding and other bio-mechanical functions. Sonomicrometry crystals are usually implanted inside the skeletal or cardiac muscle tissues to track length changes during activities such as heart-beat, chewing etc. However, sonomicrometer devices cannot be used to treat or diagnose medical conditions in animals or humans.

Why is it said that some birds can predict weather using infrasound?

           Animals are always thought to be intelligent enough to sense changes in environment. But a few studies in recent times suggest that some birds too are equally smart. For example, the golden winged warblers.

            In April 2014, a massive thunderstorm caused a series of tornadoes to tear through the Southern and Central United States. But something interesting happened just a day or two before this disaster – large flocks of golden winged warblers fled the area. Scientists say that the birds’ behaviour was caused by their ability to sense infrasound, which was an early warning sign.

            Other species that are sensitive to weather changes are seagulls and African guinea fowls. Apparently, seagulls get to hear low frequency sounds caused by large storms and also, earthquakes. This prompts them to fly inland before these disasters happen. So also is the case with African guinea fowls – they predict weather and change their nature accordingly.

Why is it said that some animals use infrasound for communication?

            There are many animals that use infrasound for communication. One of the best examples is the elephant. Research has proved that the vocal communication of these mammals ranges down into lower frequencies. As a result, the sound waves get carried farther, and reach elephant groups that are located very far away.

            Interestingly, tigers also produced infrasound, along with a variety of other sounds. This is said to help them maintain their hunting grounds. Their low frequency sounds at 18 Hz and below, most of which are inaudible to humans, drive away rivals from their territory, and also attract mates. Such sounds not only cover long distances, but also penetrate dense forests.

            In addition to these two, there are many other animals that produce infrasound. Examples of these are giraffes, alligators, hippos, and marine mammals like humpback whales.

 

Why is it said that some animals can hear infrasounds?

            Since time immemorial, there have been stories, legends, and reports on the sensitivity of animals towards different kinds of sounds.

            But the most commonly heard reports are on how some animals detect infrasonic sounds before natural disasters. As per one of the latest reports, animals like buffaloes, goats and dogs were found unharmed along the Cuddalore coast of India, where thousands died following the tsunami of 2004. People around the region said that many animals fled the area hours before the incident took place.

            Another group of animals that are said to have the ability to sense disasters are cats. Not just smaller animals, large once like elephants too grow restless prior to dangerous natural occurrences.

            Although many studies have been made, the reason for such strange behaviour in animals is yet to be confirmed.