Silencer Theory


non-mathematical explanation of the reduction or suppression of sound from gas producing devices such as firearms, internal combustion engines, compressors, air-powered tools, and industrial exhausts. Well-illustrated with many examples.


Silencer Theory (Revised, 2000)  by Henry C. Landa, et al


Table of Contents


What is Sound?

Compressions and Rarefactions

Explosions, Reports, and Exhausts

Sound Reduction

Point of Origin of Sound

How Sound Is Transmitted

How Sound Travels Through the Air

Sound Absorption and Reflection of Materials

    Sound Absorption of Various Materials

Typical Silencer Designs

    Straight-Through Expansion Box

    Absorptive Silencers

    Resonating Chamber Not in the Gas Path

    Constriction in Flow path

    Interference Filter

Firearm Silencing

Expanding and Absorbing the Gas Impulses

Lowering the Rate of Release

Rate of Release (of Gas)  vs. Time [Charts]

Practical Matters

The Firearm Silencer and the Law



Direct Price: $7.00 postpaid (paperback version)

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FICOA, 5928 W. Michigan St., Wauwatosa, WI 53213-4248



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                               Feb. 2013