Audio Engineering

698 Chapter 23

where Yem is electrical admittance due to mechanical circuit

G

R

B

em

em

em

electrical conductance

electrical s





⎛ 1

⎝

⎜⎜

⎜⎜

⎞

⎠

⎟⎟

⎟⎟

uubceptance

em

em

em

11

X

C

L

ω

ω

⎛

⎝

⎜⎜

⎜⎜

⎞

⎠

⎟⎟

⎟⎟

thus

j

em

m

m

ZL

Bl

R

C





22

1

ω

⎛

⎝

⎜⎜

⎜⎜

⎞

⎠

⎟⎟

⎟⎟

(23.31)

from ohmsem

m

R

Bl

R



22

(23.32)

C

Lm

em Bl

 22 Farads (23.33)

LCBlem  m^22 Hendries, (23.34)

where Rm is Kg/s (mechanical ohms), Lm is Kg, and Cm is meters/Newton and, by
inversion,

R

Bl

em Rme

 Mechanical ohms

22

(23.35)

C

L

em Bl

 e Metres/newton

22 (23.36)

L

L

Bl

e

me 22 Kg. (23.37)

It will be noted that in the analogue inductance (mass) in the mechanical circuit will
become a capacitance in the electrical circuit, etc.

At mechanical resonance

ω

ω

L

m Cm



1

0

⎛

⎝

⎜⎜

⎜⎜

⎞

⎠

⎟⎟

⎟⎟

(23.38)