These were notes I recorded in my Notepad on the 30th of september. The tutor went through a PowerPoint explaining how sound waves travel, how many khz humans can hear, the types of microphones and how they receive sound and how Acoustics can affect a sounds output.
First of all, what are Soundwaves?
Soundwaves are vibrations that travel through media. The media outlets can be speakers, earphones, instruments, our voices, but most of them travel in longitudinal waves that reaches our ears or, if in a room with acoustics, can also create echoes that reflect off the walls.
Studying Sound wave frequencies;
During the presentation our tutor informed us that we as humans can hear 20khz – 20,000khz. He then showed us a video that showed us how different speakers have different limits in terms of how much sound (in khz)they can produce, the video play sounds from 0khz – 20,000khz and the speakers producing the sound stopped being heard around 17khz because the speakers could not produce any more low frequencies.
// Notes made;
// Acoustics – Reflect off the wall, then create echoes.
// Canyon – Having more distance creates a longer echo.
// Refraction – Is the change in direction of a wave passing through one medium to another, or a gradual change in medium.
When sound travels through the signal path, and turns into energy it creates sound energy, which then converts the energy into Aucoustic energy, before transferring into the instrument or whatever output source is being used, then releases that energy, then converts it back into electrical energy. (Correct me if I’m wrong, these were jotted down notes).
Then the tutor taught us about two different types of microphones that are a Dynamic microphone also a Condenser microphone, both having different qualities and different Polar patterns.
Dynamic Microphone;
The dynamic microphone has a magnet, and a diaphragm to which a coil is attached. As the sound waves hit the diaphragm, this causes the coil to move backwards and forwards within the magnetic field and as a result an electric current is induced in line with the incoming sound vibrations.
Condenser Microphone;
Condenser microphones are used to capture vocals and high frequencies. Things I have noticed is that they can convert Acoustic energy into an Electrical signal, These microphones do not need alot of power supplies and a best for studio applications (48 Wots, Power switch).
Microphones have different Polar patterns;
The dynamic microphone has a Cardioid meaning the mic picks up sound in the direction it is being pointed, and cancels out any sound coming from behind it. In a live performance, it is used to make the singer louder than the audience and doesn’t pick up any background noise, making it ideal for some live performances.
Figure of 8 microphone;
A Figure-8 microphone is sensitive to sound coming from the front and coming from the rear, but has a very high rejection for sound coming from the sides. A figure 8 microphone can barely pick up any sound for the sides of the microphone.