Phat Mufflers

Shut Up Your Fans With The Phat Muffler!

The Phat Muffler is the best and most recognized 4” Duct & Fan Muffler on the international market—easily handling the loudest fan noise, giving you peace of mind.

  • Aluminum outer shell—extremely lightweight and rustproof means easy hanging or fan attachment.
  • Glass fiber instead of acoustical foam —glass fiber has a Noise Reduction Coefficient (NRC) of 85% versus 50% for foam.
  • End flanges with inner taper of 45 degrees versus a flat 90 degrees with other brands to further eliminate sound. The inner taper of the flanges helps prevent sound waves from escaping.
  • Inner mesh holding with expansive open-air perforations—allows the maximum amount of sound waves to enter the thick bed of glass fiber where the sound is transformed into heat as it passes through each glass fiber.
  • Comes in Large and Mini sizes—mini sizes give you an option in a tight space where you don’t have enough room for the standard size, and are twice as Phat as the standard models, giving you more sound attenuation in a small package.

 Phat Muffler

Phat Muffler Sizes


Muffler Diameter Length & Mouth (mm / inches)

Thickness of Glass Pack

4" 160x560x104 / 6"x22"x 4" mouth 2.8cm / 1 inch
4" Mini 215x280x104 / 8.5"x11"x 4" mouth 4 cm / 1.6 inches
6" 215x660x155 / 8.5"x26"x 6" mouth 2.8cm / 1 inch
6" Mini 260x330x155 / 10"x13"x 6" mouth 5 cm / 2 inches
8" 263x760x206 / 10"x30"x 8"mouth 3 cm / 1.25 inches
10" 320x890x257 / 12.5"x35"x10"mouth 3 cm / 1.25 inches
12" 370x900x308 / 14.5"x35.5"x12" mouth 3.5 cm / 1.4 inches

Superior Noise Reduction

Phat Mufflers use an extra thick glass fiber pack with a Noise Reduction Coefficient (NRC) of 0.85 versus 0.50 for foam based mufflers.  

Phat Muffler

Phat Muffler Dimensions

The Phat Mini Mufflers are doubly thick to compensate for them being short—allowing them to fit into tight spaces.

12-inch-muffler-dimensions10-inch-muffler-dimensions 8-inch-muffler-dimensions 6-inch-muffler-dimensions6-inch-short-muffler-dimensions 4-inch-muffler-dimensions4-inch-short-muffler-dimensions


Place your Phat Muffler on the intake side of your fan/blower for maximum sound attenuation if you only have one muffler. For maximum sound attenuation on a blower/filter line, place one muffler on the blower intake and one muffler on the blower outtake.

Phat Mufflers are not directional—they can be positioned so that air blows through them in either direction. 

For a tight, solid fit, self-tapping sheet metal screws can be put through the Phat Muffler flanges directly into your fan if desired. Duct tape can also be used.

Mufflers should not get wet. If your muffler gets wet, dry it out thoroughly so it will work correctly.

Phat mufflers should be the same diameter as your duct size unless you want to increase the air pressure intentionally.

To hang a Phat Muffler, you can tap into the muffler housing with sheet metal screws or hang it with chain or rope that is wrapped around the muffler housing.