neverest® ESD 4" Adjustable Inline Duct Silencer – Modular Sound Absorbing

I have a stand size HVAC vent in my basement directly above my Home Theater couch. The 6" duct is far too big (especially as the first duct off the main branch!) It was extremely loud and disruptive. No way to install a damper in the duct. No vent cover grate could surpress and silence the huge air flow. Stuck this 6" (really 6.3") device into the duct behind the grate. Removed 1 hole. Perfect!! Quiet. Normal vent airflow. Even improved airflow to other vents in the house!! I'd give this 10 stars out 5 if I could. Amazing!

Recently moved into a home with a very cramped plenum (doohickey above the air handler that disperses the air through various ducts). Somewhere in that is a hard angle or two which makes the air really reverberate through specific ducts in my basement. Since it is fairly impossible to get to the actual source of the noise, I *luckily* happened across the neverest insulation silencers. They're a very simple idea: round squishy "foam" that you shove into your round ducts. These foam inserts have a number of cutouts in them so you can choose how much air to let through vs how much noise to bounce back down the duct. Yeah, it cuts down the air a bit coming out of the duct. But, it's well worth it - I no longer feel like I have the cheap seats in an airplane next to the freaking engine. Installation was simple: pull out a few of the cutouts on the foam inserts, remove the register, shove 1 or 2 in there, replace register.

Ordered and installed 2 of these in flexible 4" air intake ducting for a diesel heater. Overall has helped to reduce the whooshing noise from the inlet considerably, though install was a bit tricky given the diameter did not match the flex duct size perfectly and needed to be trimmed a bit to fit without crushing.

Does not work well for me

I did not notice any muffling or dampening of the sound, even with several plugs installed.

This has greatly reduced the sound coming into my bathroom. It was very easy to install, so long as you're comfortable getting on your roof. Airflow has been slightly impacted; the static pressure was increased as a result so my fan sounds slightly louder. I actually found this to be a good thing; my dog is terrified of fireworks and my bathroom is now the best place for him to hide when fireworks are going thanks to these and the increased fan sound. I think most people would think that's a negative but it works for me! You can easily add more than one to increase the sound dampening ability of the silencers, but that will increase the static pressure and fan noise. Just a word of warning

I lined 2-3 of these in a row in some of my ducts with a little over half of the insets punched out as holes and the remaining protruding halfway out to form a kind of rotated interlocking sound maze of baffles. Lets air throught and seems to work very well to trap and cut sound down 80-90%. Went from it sounding like people were talking directly into the vents to pretty much nothing Definitely does squat if you buy only one and take all the insets out and expect it to magically block sounds. That's not how sound waves work.

I had a return duct that was connected via pipe to the return duct near the fan in the bedroom. The air noise was quite loud and very noisy since it was in the bedroom. I placed 2 of these insulators in the duct and the results are outstanding! The duct noise is hardly noticeable and the air flow is adjustable. Highly recommend!

Piccolo ma con un ottimo abbattimento del suono. Ho liberato 3 fessure, l’aria passa bene il suono viene fortemente smorzato se non annullato del tutto già ad una distanza di 1m. Ottimo prodotto… costa ma ne vale la pena

Works great

Atténuation du bruit trop faible !

Bought to stop draught coming through vent, perfect!

La reducción de las frecuencias de la voz humana es notable