Tag Archives: Audio

Audio Frequency Range and Electronic Components

A vast majority of people like to listen to some form of audio. Be it in cars, homes, or theaters, audio is prevalent, and its applications are growing with the increasing use of portable devices. In all audio systems, important factors for a portable audio device are its design, size, cost, and quality. But listeners judge the performance of an audio device primarily on the basis of its capability to recreate the necessary audio frequencies.

The audio industry commonly refers to the frequency range that humans can hear and perceive as 20 Hz to 20,000 Hz. Although the average human can distinguish far less than this range, the ability depends on the age and health of the individual. For instance, with age, this range inevitably shrinks, with the loss being more pronounced at the higher frequencies.

Experts divide the perceptible audio spectrum into seven subsets. Starting with the sub-bass subset whose frequency ranges from 16 to 6 Hz, is the primary low range of musical instruments. Then comes the bass frequencies ranging from 60 to 250 Hz, and this is the normal speaking vocal range. Next is the lower mid-range of brass and wood instruments covering the range of 250 to 500 Hz. Mid-range frequencies follow next, covering 500 Hz to 2 kHz, where the higher end of fundamental frequencies of most musical instruments lies. The next range is the higher mid-range, covering 2 to 4 kHz, where the harmonics of most instruments are present. The next range is the presence ranging from 4 to 6 kHz, and this is where the harmonics of string instruments are. The last subset is the brilliance, ranging from 6 to 20 kHz, where the most whiles and whistles are present, and where the harmonics of most percussion instruments lie.

For visualizing and quantifying audio frequencies generate by most audio devices and electronic components, experts rely on frequency response graphs. These graphs are a plot of the sound pressure level at a specified distance plotted against frequency. For instance, a buzzer puts out an audible tone, which features a narrow frequency range on the response graph. On the other hand, audio speakers feature a wide frequency range coverage, as they must recreate sound and voice more faithfully.

A typical frequency response graph for electronic components generating sound depicts the sound pressure level or loudness on its Y-axis on a logarithmic scale, while the X-axis represents frequencies on a logarithmic scale. For electronic devices that sense audio input, such as microphones, the frequency response graph shows sensitivity as sound pressure level on the Y-axis on a logarithmic scale. Most of the frequency response graphs represent a constant power input to the device under measurement.

The frequency response graph is an important document for selecting electronic components for a specific application. For instance, it can differentiate whether a particular speaker will be a good performer for the entire audio frequency range, or it will be suitable for bass frequencies alone. Similarly, the frequency response graph for a microphone will characterize it as suitable for a concert or for instrumentation.

Speakers: Sound From Any Surface

Although accustomed to thinking about speakers when we hear of sound reproduction, nature uses several methods of producing sound or amplifying it. For instance, a cricket makes a chirping sound by rubbing its hind legs against each other, while perching on a large leaf to amplify the sound it produces. A guitarist amplifies the sound from the wires by coupling it to the guitar’s wooden box.

Traditionally, the size of the cone and the driver of a speaker determine the frequency and range of sound it produces. That is why several small portable speakers sound tinny, as they are unable to offer the deep bass because their driver can deliver limited frequency ranges. That is also the reason high fidelity audio systems have separate speakers for reproducing extremely low frequencies through subwoofer speakers.

A new type of speaker in the market does not require a cone to reproduce sound. This speaker uses the Incisor Diffusion Technology to diffuse sound across and through any surface upon which it is resting. It uses the surface to act as its cone and the surface diffuses the sound into the surrounding area.

Created by Damson, all its products using the Incisor Diffusion Technology offer a full audio frequency range from the surfaces they are placed upon. However, as different surfaces have varying resonance properties, the audio they produce will sound somewhat different. This unique way of reproducing sound offers the hearing impaired to feel sound through vibrations—just as Beethoven did.

As Damson pushes the capabilities of sound reproduction to newer frontiers, the need for different speakers to provide bass, middle, and high frequencies is fast dissolving. A regular speaker has a coil fixed to a permanent magnet, the arrangement being known as the driver. The Incisor Diffusion Technology from Damson replaces the coil with teeth or incisors. While they act in the same way as a coil does, they also power the different frequencies pushing the through to the surface. The reaction of the Incisor Diffusion Technology with the surface transfers the sound through it. For instance, placing on of Damson speakers on a window diffuses the sound through the glass, allowing it to be heard on both its sides.

Along with the size and shape of the surface, its type also affects the sound that it delivers. For instance, a bigger surface produces more sound than a smaller surface does, as it has more area and moves a greater amount of air—just as a bigger speaker is louder than a smaller one is. Any elastic surface will work to amplify the sound through it.

That means some surfaces work better than others do when reproducing sound. For instance, you will not hear sound from surfaces made of granite or stone, thick solid wood, sand, tarmac, grass, mud, asphalt, and concrete. On the other hand, thin wood is an ideal surface for sound reproduction, as is glass such as windshields, shower screens, windows, and tables. Metals surfaces are also good for sound production, so one can use the car bonnet, hood, or the roof. Now Redux is planning to use this technology on the screen of smartphones as a replacement for tiny speakers.