This slide talks about sound and microphone in brief.

1. Sound and
Microphone
Prepared by:
Shubhanshu Pathak
2015-2016 July
Batch

2. Sound
Sound is a vibration that propagates as a
typically audible mechanical wave.
Sound travels at a speed of 334 m/s.

3. Physics of Sound
 Sound travels in a Medium.
Sound waves are generated by a sound source
such as vibrating diaphragm of a speaker.

4. Components of Sound
Wave
Wavelength
Amplitude
Velocity

5. Components(contd.)
Envelope
Phasing
Harmonics
Frequency

6. Types of Sound Waves
Longitudinal waves
Transverse waves
Stationary waves.

7. Octave
Range of audible frequency is divided into
audio band.
Octave is the interval between any 2
frequencies having tonal ratio of 2:1.
There are 3 Octaves:

8. Octave(contd.)
Bass: Consists of 4 octaves and is divided into
2 groups.
Mid: Consists of 4 octaves and is divided into
2 groups.
Treble: Consists of 2 octaves.

9. Microphone
A microphone is a transducer that converts
sound into an electrical signal.
First proper microphone was developed by
David Hughes, in the US in, 1877.

10. Components
Capsule: The transducing element.
Diaphragm: The moving film.
Housing: Brings signal from element to other
equipments.

11. Polar Pattern
Three prominent polar patterns are:
1. Omnidirectional.

12. Polar Pattern(contd.)
2.Bidirectional(Figure of eight)
3.Directional(Cardioid).

13. Types
Condenser microphone:
The were invented at bell labs.
They work on the principle of variable
capacitance.

14. Moving coil Microphone
They work on the principle of electromagnetic
induction.
The sound is produced by the motion of the
coil.

15. Ribbon Microphone
They work on pressure difference.
A thin aluminium foil motion produces voltage
which a transformer boosts.
They are used for percussion instruments.

16. Properties
Frequency response.
Overload limit.
Maximum SPL.
Sensitivity.
Self Noise.
Signal to Noise ratio.
Proximity effect.

17. Sennheiser MD421
Glass composite housing and hardened
stainless steel basket.
Frequency response 30Hz-17kHz
Effective feedback rejection
Clear sound reproduction.

18. Conclusion
Microphone are of great importance for audio
industry.
Proper care is to be taken in selection and
handling of a microphone.