AC Infinity Duct Silencer, 6" Inline Muffler with Neoprene Foam

My house air filtration system incorporates Merv13 + hepa + carbon cylinder + RAM 150mm fan + 8 meters of ducting. The noise at the outlet was 73db. Installed the silencer about halfway in line. Noise dropped to 63db (almost half audible). Unfortunately, air flow reduced by 10% - in my system went down from 3.0 m/s (85 m³/h) to 2.7 m/s (76 m³/h). Note that my RAM is rated at 517 m³/h, and the real life readings are due to multiple filters restricting. The airflow is just about enough for two people.

I installed it in my basement to reduce noice between basement room and the kitchen. Works great, I noticed significant reduction

didn't do that much on high speed but for low speed did some worth mentioning the 6 inch came black ( it's a new model ) i think it's much better but easily get scratched

Install motorized zone dampers in ductwork. Noise much lower to the point I don’t hear them opening and closing anymore out my registers.

Der Rohrschalldämpfer (150mm) funktioniert einwandfrei, er macht was er soll. Insgesamt sind die Abluftgeräusche durch den Rohrschalldämpfer deutlich geringer. Ich kann den Rohrschalldämpfer nur empfehlen.

Just installed a Panasonic ERV which is quiet and well built. The output fresh air picks up turbulent air noise from the flex duct and is annoying and too loud to be comfortable. I switched from 6 in accordion flex duct to flex smooth aluminum duct but still too noisy. I checked with Chat GPT and it suggested an inline muffler. Found the AC Infinity muffler, order and arrived next day. Just placing the muffler over ear attenuated almost all sound. Installed easily and immediately at the termination end of duct exit port. Sound is much quieter, appears to be 65/70 % attenuation. The howling sound is mostly gone and only the sound of air flow left. I would buy again without hesitation. Very pleased.