Sound Transmission through Duct Walls

Sponsored Links

Sound transmitted from the inside of a duct to the surrounding room can be expressed as:

L_p = L_w - TL - 10 log( A F / 4 A_d )         (1)

where

L_p = sound pressure in room (dB)

L_w = sound power level in the duct (dB)

TL = transmission loss through duct wall (dB)

A = room absorption (m² sabine)

F = cross section area of duct (m²)

A_d = surface area of duct (m²)

Transmission loss through duct walls are indicated in the table below:

Sponsored Links

Related Topics

• Acoustics - Room acoustics, acoustic properties - decibel A, B and C - Noise Rating (NR) curves, sound transmission, sound pressure, sound intensity, attenuation and more ..
• Noise and Attenuation - Noise is usually defined as unwanted sound - noise, noise generation, silencers and attenuation in HVAC systems

Related Documents

• Classification of Noise Reduction Silencers - Eliminating noise with reactive silencers - diffuser type silencers - active silencers and/or dissipative silencers
• Sound Attenuation - Duct split to Terminals - Estimation of sound attenuation when ducts are split to terminals
• Sound Attenuation - Main Duct to Branches - Sound attenuation for main ducts to branches.
• Sound Attenuation due to End Reflection - Some of the low frequency noise transferred to the end terminals in a ventilation system, reflects back to the duct.
• Sound Attenuation in Duct Elbows - Noise attenuation in a duct elbow is caused by reflected sound. It is only in larger ducts and at higher frequencies the attenuation is considerable
• Sound Attenuation in Unlined Sheet-Metal Ducts - Attenuation of sound in unlined sheet-metal ducts
• Sound Attenuation of Lined Sheet-Metal Ducts - Sound attenuation in rectangular straight, lined, sheet metal ducts
• Sound Transmissions through Flanking Paths - Noise and sound transmitted through duct walls, through floors or through ceilings