Home Blog Page 3

What Is Phase?

Starting Sound
-
0
What Is Phase?

When it comes to sound theory, phase is a topic that is often overlooked. However, understanding what is phase in the context of sound engineering is important to be able to understand and address issues about sound further down the road, for example with the use of microphones.

Phase In The Context Of Sound

Just like how we may describe the moon going through phases each month – from being a new moon to a crescent to a quarter and so on – a sound wave can also be said to go through phases.

1 Cycle

One cycle of a sound wave goes through one peak and one trough before returning to its starting point.

Phases

This one cycle can be broken up into four phases:

  • the start of the wave at the neutral pressure position (0 degree) to the peak (90 degrees)
  • the peak (90 degrees) back to the neutral position (180 degrees)
  • the neutral position (180 degrees) to the trough (270 degrees)
  • the trough (270 degrees) to the neutral position (0 degree)

Constructive Interference

Phase becomes particularly important when dealing with two or more sound waves interacting with each other.

Constructive Interference

If two sound waves are exactly aligned with each other, they are said to be in phase with each other. The two sound waves will reinforce each other and result in constructive interference.

In observable terms, constructive interference will result in an increase in the combined sound wave’s amplitude.

It is a case of amplitude 1 + amplitude 1 = amplitude 2.

Destructive Interference

Destructive Interference

On the other hand, if two sounds waves are exactly the opposite of each other, they are said to be 180 degrees out of phase. In this case, cancellation, also known as destructive interference will occur.

As in the diagram above, if the amplitude of one wave is +1 and the amplitude is -1, the result will be the summed up to be an amplitude of 0, which results in silence.

Example of Constructive & Destructive Interference

Watch the video below to see constructive and destructive interference in action.

Phase Problems in the Real World

You might be thinking that while this may all be very interesting, such phase cancellations don’t exist in the real world.

While you may not experience complete destructive interference, phasing issues can have often be found in several scenarios. The most common scenario would be when multiple microphones are picking up the same sound source.

Phase Problems in the Real World

Imagine a situation where two microphones, A & B, are being used to pick up a single source. However, microphone B is positioned slight further away than microphone A. This resulting in the sound waves arriving at the microphone B a millisecond later than at microphone A.

This causes the sound from microphone B to be one millisecond behind microphone A. This can result in destructive interference of specific frequencies, resulting in the combined sound from the two microphones sounding weak or unusual.

View a demonstration of phasing issues in the video below.

Next, you may wish to read all about harmonics and overtones.

What Is Amplitude?

Starting Sound
-
0
What Is Amplitude?

Amplitude is a term that sound engineers may come across. Sometimes, it is casually substituted with the word “loudness”. What exactly is amplitude and how does it relate to sound?

What is Amplitude?

Amplitude is a measure of how much energy is behind a particular sound wave. This represents how “strong” a sound wave is.

To the human ear, in general, the larger the amplitude of a sound wave, the louder it will sound.

Sound wave

When you look at at a graph of a sound wave, on the horizontal axis is time. The vertical axis is amplitude.

If the peak of Wave A is twice as high as Wave B, it can be said Wave A has double the amplitude of Wave B.

Measuring Amplitude

The unit of measurement for amplitude is dB SPL (Sound Pressure Level).

Here are some examples of amplitude for different everyday sounds:

Threshold of hearing (i.e. near silence): 8 dB SPL
Leaves rustling: 20 dB SPL
Vacuum cleaner: 80 dB SPL
Jack hammer: 100 dB SPL
Rock concert: 120 dB SPL

Difference between Amplitude and Loudness

It is tempting to consider amplitude to be the same as loudness. To the general person, this will seem to be the case, but there are some differences to be aware of.

Decibel Meter

Amplitude is an objective measure of sound pressure levels. It can be measured using a sound level meter (also known as a decibel meter) that returns a reading of the amplitude of a sound.

Loudness is a subjective perception. What may be loud to one person may not be loud to another person.

In sound engineering terms, we would normally be dealing with amplitude.

Difference between Amplitude and Frequency

It is important to grasp the difference between amplitude and frequency. The two are separate and independent of each other.

High Frequency sounds with different amplitudes

It is possible to have a sound that has a high frequency and high amplitude. A sound that has high frequency can also have a low amplitude.

Difference between amplitude and frequency

Similarly, a low frequency sound can have either a high or low amplitude.

Pink Noise Ear Training For Sound Engineers: 2 kHz, 18 dB Cut

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 2 kHz, 18 dB Cut

As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 2 kHz, 18 dB Cut

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of randomized sound. Compared to White Noise, Pink Noise has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB cut at 2 kHz. Use it to learn to identify the 2 kHz frequency.

For best results, listen using headphones.

Dynamic Vs Condenser Microphones

Starting Sound
-
0
Dynamic Vs Condenser Microphones

The most common types of microphones that you will come across when working in live sound are dynamic and condenser microphones. Understanding the difference will allow you to better decide which to use in what type of situation.

Dynamic Microphones

How Do Dynamic Microphones Work?

How Do Dynamic Microphones Work?

The most common type of microphones are dynamic ones. They are favoured because they are durable, affordable, and all-purpose in design.

Dynamic microphones convert sound into an electrical signal by using a moving coil and magnet. At the front of the microphone, a diaphragm, which is designed to move back and forth with incoming sound waves, is connected to the coil of wire that sits in a magnetic field created by magnets.

When the diaphragm is struck by sound waves, the coil moves back and forth in the magnet’s magnetic field. This produces a very small electrical current, which is then transmitted out of the microphone, down the cable to the mixer.

Characteristics of Dynamic Microphones

Dynamic microphones are strong and made to withstand loud noises, making them ideal for live performances where they may be exposed to such noises.

They are also made to withstand the abuse and wear and tear that comes about with frequent use.

Dynamic microphones do not need an external power source to work. Instead, they rely only on the mechanical energy of the sound waves striking the diaphragm to function.

As a result, dynamic microphones are less sensitive than condenser microphones. This means that they might not be able to capture every fine detail of a performance.

They are considered to be a dependable and durable type of microphone and are frequently used in live performance settings, particularly for vocals and drums. Their durability means that they can usually continue to work even if a vocalist drops them, and their ruggedness allows them to handle high Sound Pressure Level situations such as the sound of drums being hit.

Condenser Microphones

How Do Condenser Microphones Work?

Condenser Microphones How Do Condenser Microphones Work?

Condenser microphones capture sound by generating variations in electrical voltage. This is as opposed to dynamic microphones by using a magnetic field.

Just like a dynamic microphone, a condenser microphone also has a diaphragm that moves in response to the incoming sound waves. A metal plate is attached to the diaphragm.

There is an electrical charge between the metal plate and a separate back plate. This can be thought of as an electrical reservoir, also known as a capacitor. Condenser is an old term for a capacity.

The “reservoir” is disturbed when the diaphragm moves. This causes “ripples” that are then sent out of the microphone as the audio signal.

Condenser microphones need an electrical power source to work. This is used to create an electrical charge to build the “reservoir”.

This electric charge can either come from a battery in the microphone or from the mixer. Phantom Power is a small voltage sent by the mixer through the microphone cable  to power up condenser microphones.

Characteristics of Condenser Microphones

Condenser microphones are more responsive and audibly sensitive. They are suited for capturing the finer details of cymbals, violins, and other high-frequency instruments because they frequently react favorably to high-frequency sounds.

However, you can also find condenser microphones being used for vocals and acoustic instruments like pianos and guitars as well.

Read more about different types of microphones.

Compression And Rarefaction In Waves

Starting Sound
-
0
Compression And Rarefaction In Waves

There are two main types of wave motion for mechanical waves. These are longitudinal waves and transverse waves.

Sound waves are longitudinal waves.

What is Compression and Rarefaction?

Longitudinal waves means that the displacement of particles progresses in the same direction as the wave.

Sound is created by vibrations and requires a physical medium to travel through.

The longitudinal waves are manifested in a series of compressions and rarefactions.

Compression occurs when the energy from the sound source pushes the molecules towards each other, resulting in a decrease in the distance between the particles of the medium.

The opposite of compression, rarefaction is characterized by an increase in the distance between the particles of the medium.

This results in a series of compression and expansions that we know as sound waves. These compressions and expansions can take place thousands of times per second.  

The sound waves carry information away from their source to reach your ear drums and brain — and we then perceive them as sound.

This rate that these compressions and rarefactions take place is known as the sound wave’s frequency. How fast or slow these waves occur, i.e. their frequency, then gets perceived by us as different pitches.

Speed of sound

Sound travels at different speeds depending on several factors such as temperature, humidity and elevation from sea level. In general terms:

  • at 20°C (room temperature), air will transmit sound at 343 m/s (1125 ft/s)
  • at 40°C (hotter than room temperature), air will transmit sound at 1100 m/s or 3372 ft/s

Pink Noise Ear Training For Sound Engineers: 1 kHz, 18 dB Cut

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 1 kHz, 18 dB Cut

As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 1 kHz, 18 dB Cut

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of randomized sound. Compared to White Noise, Pink Noise has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB cut at 1 kHz. Use it to learn to identify the 1 kHz frequency.

For best results, listen using headphones.

Pink Noise Ear Training For Sound Engineers: 31 Hz to 16 kHz, 18 dB Cut

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 31 Hz to 16 kHz, 18 dB Cut

Train your ear to identify the frequencies from 31 Hz to 16 kHz with an 18 dB cut. As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 31 Hz to 16 kHz, 18 dB Cut

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of sound. Compared to White Noise, it has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB cuts at the following frequency intervals: 31 Hz, 63 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 16 kHz.

For best results, listen using headphones.

Pink Noise Ear Training For Sound Engineers: 500 Hz, 18 dB Cut

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 500 Hz, 18 dB Cut

As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 500 Hz, 18 dB Cut

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of randomized sound. Compared to White Noise, Pink Noise has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB cut at 500 Hz. Use it to learn to identify the 500 Hz frequency.

For best results, listen using headphones.

Pink Noise Ear Training For Sound Engineers: 250 Hz, 18 dB Cut

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 250 Hz, 18 dB Cut

As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 250 Hz, 18 dB Cut

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of randomized sound. Compared to White Noise, Pink Noise has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB cut at 250 Hz. Use it to learn to identify the 250 Hz frequency.

For best results, listen using headphones.

Pink Noise Ear Training For Sound Engineers: 16 kHz, 18 dB Boost

Starting Sound
-
0
Pink Noise Ear Training For Sound Engineers: 16 kHz, 18 dB Boost

Train your ear to identify 16 kHz with an 18 dB boost. As a sound engineer, the most important skill that you can have to is have good ears. This means training your ears to be able to identify what you are hearing. Once you are well versed in listening out to different frequencies, you will be able to create the perfect audio experience for your audience.

Pink Noise Ear Training for Sound Engineers: 16 kHz, 18 dB Boost

Anyone can train their ears to listen and identify different frequencies.

The Pink Noise Ear Training Video below will train you to identify different frequencies..

The video makes use of Pink Noise. Pink Noise is a type of sound. Compared to White Noise, it has more energy at the lower frequencies and replicates how the human ear hears sound.

This Pink Noise Ear Training Video alternates between Pink Noise and 18 dB boost at 16 kHz. Use it to learn to identify the 16 kHz frequency.

For best results, listen using headphones.

1234...6Page 3 of 6

Develop

Resources

Other

© Starting Sound. All rights reserved.