A sound attenuator, or duct silencer, sound trap, or muffler, is a noise control acoustical treatment of Heating Ventilating and Air-Conditioning (HVAC) ductwork designed to reduce transmission of noise through the ductwork, either from equipment into occupied spaces in a building, or between occupied spaces.
Do attenuators reduce noise?
Duct attenuators, also called silencers, are used to reduce noise radiated from the inlet and the outlet of fans and other air handling equipment.
What does a duct silencer do?
An HVAC duct silencer is specifically engineered to reduce airborne noise carried along ducts or produced by enclosures. You’ll also find these silencers described as sound attenuators when they are used in industrial settings.
How do you reduce air duct noise?
High static pressure makes airflow more audible
- Adjust the fan speed. Your blower or furnace fan should be set to deliver the proper airflow per ton.
- Add ductwork.
- Add a bypass duct.
- Add or expand grilles and registers.
- Replace existing registers and grilles with high velocity models.
Where do you put a duct silencer?
The duct silencers are designed mainly to attenuate noises in ventilation ducting. In most cases, they are mounted between the fan and the diffusing or exhaust fan and before the air diffusers. Duct silencers should be installed behind fans, flow regulators.
Why is my air vent so loud?
Vents can make loud whooshing noises if the supply air ducts are too narrow. Debris can also block the ducts or cause one or more vents to close. You can use a flashlight to see if the vents look too dirty. However, you’ll need to reach out to an HVAC contractor if the noise persists.
How does attenuation affect noise?
In a nutshell, attenuation is the loss of transmission signal strength measured in decibels (dB). As it increases, the more distorted and unintelligible the transmission (e.g. a phone call or email you’re trying to send) becomes.
What is the noise figure of an attenuator?
The Noise Figure of a passive attenuator is the attenuation value of the attenuator. This is because noise figure is by definition the difference in the SNR of the output and the SNR of the input, with the input terminated with the characteristic impedance of the system (typically 50 ohms).
How does duct muffler work?
These are specially designed for the purpose of stifling and insulating sound which is created by air duct equipment such as fans and AHUs. They act as a sound dampener, reducing vibrations and sounds through the production of expansion joints and compensators which absorb sound.
Where should a duct silencer be placed?
Why do my air ducts make noise?
WHY ARE MY AIR DUCTS POPPING AND BANGING? One of the main causes for these loud noises are differences in pressure between the supply and return ducts. Another common cause is expansion and contraction due to changes in temperature.
Do air duct mufflers work?
While there are multiple methods of reducing air duct noise, the use of air duct silencers will not only reduce unpleasant fan noise significantly but will greatly reduce the amount of cross-talk which is transmitted and conducted through these vents.
What is the purpose of sound attenuators in duct work?
A sound attenuator, or duct silencer, sound trap, or muffler, is a noise control acoustical treatment of Heating Ventilating and Air-Conditioning (HVAC) ductwork designed to reduce transmission of noise through the ductwork, either from equipment into occupied spaces in a building, or between occupied spaces.
What is the function of sound attenuator?
An attenuator reduces an input signal to a lower level. The amount of attenuation is specified in decibels (dB). Decibel values are additive for cascaded attenuator sections. dB from power ratio: dB = 10 log10 (PI / PO) dB from voltage ratio: dB = 20 log10 (VI / VO) T and Π section attenuators are the most common circuit configurations.
What is a duct silencer?
Duct Silencers: Commercial – Industrial – HVAC. Silencers or Duct Silencers are an engineered product specifically designed to control airborne noise in ducts, openings in buildings, enclosures, or from equipment. They may also be referred to as industrial sound attenuators.
