Noise Reduction

**Chris Parks** · 28th June 2016, 11:21 PM

Originally Posted by DomAU

If you use a flexible HVAC duct you won't have any outdoor exhaust noise problems.

Dom, unfortunately some can't including me due to site problems. It would have been far easier, cheaper and possibly a better result if I could have and other options need to be seen by potential users. I often recommended exactly what you have done to potential new CV owners when discussing the noise issues with them prior to buying. Is the AC ducting water proof?

**safari** · 29th June 2016, 05:52 PM

Originally Posted by DomAU

If you use a flexible HVAC duct you won't have any outdoor exhaust noise problems.

Not the case in my experience. I originally used about three metres of 10" HVAC but it wasn't until I built a large muffler that I got the noise down to a reasonable level.

**DomAU** · 29th June 2016, 08:07 PM

Originally Posted by safari

Not the case in my experience. I originally used about three metres of 10" HVAC but it wasn't until I built a large muffler that I got the noise down to a reasonable level.

Did you have problems due to noise radiating from the exhaust ducting within the workshop / garage, or from the actual exhaust exit point at the end of the duct? There is still a bit of noise at the exhaust point of the cyclone that gets increasingly attenuated along the length of the HVAC duct in my case, however the actual discharge point outside the house being effectively whisper quiet.

Out of curiosity what was your exhaust point? eg. a chinamans hat, a side louver etc? Was the exhaust point rigidly mounted?

**safari** · 3rd July 2016, 11:45 AM

Sorry for the late reply DomAU. The original exhaust did not quiten the CV anywhere near enough both inside and outside the workshop. I Then used 9" flexible ducting wrapped in acoustic material from the CV outlet to the muffler and 9" flexible (without wrapping) from the base of the muffler to the outside of the shed. The length of this ducting is about 2 metres ending under an adjacent bungalow. The end of the ducting is just open and not rigidly mounted.

**shedman** · 5th July 2016, 12:37 PM

If anyone wants to let me have pictures I will put them in my gallery page on the Clearvueoz website.

**DomAU** · 5th July 2016, 04:48 PM

Originally Posted by safari

Sorry for the late reply DomAU. The original exhaust did not quiten the CV anywhere near enough both inside and outside the workshop. I Then used 9" flexible ducting wrapped in acoustic material from the CV outlet to the muffler and 9" flexible (without wrapping) from the base of the muffler to the outside of the shed. The length of this ducting is about 2 metres ending under an adjacent bungalow. The end of the ducting is just open and not rigidly mounted.

Strange. There must be something about my setup that is eliminating the exhaust noise, but it seems like the hvac duct is only a part of the explanation.

**safari** · 5th July 2016, 11:31 PM

Are you running it at 60 hertz?

**DomAU** · 6th July 2016, 07:59 AM

Originally Posted by safari

Are you running it at 60 hertz?

Yep. Sometimes at 63 Hz.

**shedman** · 6th July 2016, 11:11 AM

That sounds like a good idea! just joking I am here when you are ready.

Thread: Noise Reduction - CV1800

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