PROPERTIES OF

1
PROPERTIES OF DYNAMIC AND ELECTROSTATIC LOUDSPEAKE
RS
By TEAM 2
Taffeta, Sonja, Valeria, Susan, Christian and
Janez
Summer School in Acoustic Communication Odense,
2003
2
OVERVIEW

• Intro to speakers
• Frequency characteristics
• Directional characteristics
• Near and far acoustic fields
• Conclusions

3
Loudspeaker Types

• Electrostatic loudspeaker
• 150V across high-impedance backplate and
  metalized film
• Special amplifiers apply transduced voltage to
  polarized voltage
• Dynamic loudspeaker
• Electro-inductance transducer with low-impedance
  magnet
• Light circular diaphragm with voice coil and
  very light rectangular diaphragm extending into
  ultrasonic

4
FREQUENCY CHARACTERISTICS
SPL dB re 20 µPa
Frequency kHz
SPL dB re 20 µPa
Frequency kHz
5
DIRECTIONAL CHARACTERISTICS
SPL dB re 20 µPa
Angle ?
SPL dB re 20 µPa
Angle ?
6
Near and far acoustic fields
SPL log dB re 20 µPa
Distance cm
SPL log dB re 20 µPa
Distance cm
7
THE SPEED OF SOUND
Electrostatic loudspeaker Roomtemperature 28
C 1 m/ 2,85 ms 350,9 m/s
Dynamic loudspeaker Roomtemperature 28 C 1
m/ 2,87 ms 348,4 m/s
8
Acknowledgements

• First, thanks to the anonymous girls in Kongens
  Have for the
• frisbee (which was not cheap but timely)
• ?To Lone, for the meal tickets which were the
  most important
• part of the day
• ?To the directors of the course for their
  patience and ability
• to find us worthy for admission
• ?To our colleagues, for their good humor
• ?To the sun, which shone at the right moments, to
  the
• water for keeping the porpoises wet, and to the
  wine for
• keeping us in a like manner to the porpoises
• ?Funding agencies are thanked elsewhere