Quieting the generator

[kltgnl]

Greetings, we have a 2005 PW Dodge Plateau with an Onan generator. We have old (2007) information indicating that it is possible to quiet the generator using insulating blankets. Would like to put this to use but can't determine exactly what kind of "insulating blankets" would be appropriate (by thickness or brand or size of piece). Further details on how to attach the blanket around the generator would be helpful too. Any suggestions would be much appreciated. Thanks.

 

[Hit The Road Jack]

Greetings, we have a 2005 PW Dodge Plateau with an Onan generator. We have old (2007) information indicating that it is possible to quiet the generator using insulating blankets. Would like to put this to use but can't determine exactly what kind of "insulating blankets" would be appropriate (by thickness or brand or size of piece). Further details on how to attach the blanket around the generator would be helpful too. Any suggestions would be much appreciated. Thanks.

IMO don't suffocate your generator with heat storing blankets...

Onan Exhaust Resonator

"Noise is not measured on a linear/straight line scale - noise levels double every 3-5 dB(A)

So 73/75 dB(A) is twice as loud as 70 dB(A) or two 70 dB(A) units running together would produce between 73 and 75 dB(A)"

The National Parks standard is 67 db, at 23'.

With just the resonator you'll get a reading of 62 db at 23' (7 meters)

With the SuperTrapp and resonator 61 db at 23'.

Not a big difference, but noticeable.

The interesting numbers will be the measurements taken inside. With the resonator you'll get a reading of 60 db, and with the SuperTrapp on 55 db. I can only attribute this to the weight of the ST cutting down on the vibrations from the exhaust pipe.

http://www.dyersonline.com/Products/Onan-Exhaust-Resonator__16760.aspx

http://www.forestryforum.com/board/index.php?topic=41136.0;all

https://sprinter-source.com/forums/showthread.php?p=75723

 

[avid]

I have heard that the resonator lowers pitch of the generator so the human ear doesn't perceive it as well. Now I would like to hear from someone who has actual experience doing this. The part is cheap enough and getting it installed at the local muffler shop would cost darn little. I would do it, if it actually makes a difference.

David

p.s. It voids your generator warranty if you care.

 

[What Next]

Several of us have put on the resonator. It is not a great improvement but for the cost we thought it was worth it. Been 3 years now. It does lower the sound level slightly.

 

[aljimenez]

Here's what I did to make our generator quieter. The gen is now Honda-gen quiet: 65db right in front of it, and under 60db 20 feet away... Al

 

[kltgnl]

Here's what I did to make our generator quieter. The gen is now Honda-gen quiet: 65db right in front of it, and under 60db 20 feet away... Al

Thank you so much. If I have any questions, I would like to contact you. Is this possible? KLTGNL

 

[aljimenez]

yes, I have responded to your private e-mail... Al

 

[mike_mcginn]

After waiting 3 years, I finally had the resonator installed.
It makes a significant difference. I will be far, far less
concerned with others reaction to the noise.
I did not take any scientific measurements, so can't
comment. But I am very pleased with the difference.
I told the PW rep that I think they should offer the
resonator as a build option.

 

[avid]

After waiting 3 years, I finally had the resonator installed.
It makes a significant difference.

Were did you purchase the resonator? TIA

David

 

[Hit The Road Jack]

Here's what I did to make our generator quieter. The gen is now Honda-gen quiet: 65db right in front of it, and under 60db 20 feet away... Al

IMHO, you've cut down the life expectancy of the 'No-Ran' considerably......If the manufacturer felt trapping excessive heat with thermal blankets in lieu of limiting sound was acceptable, they'd have installed sound deadening material under the generators shroud...

The second addition, being the 'No-Ran' Resonator is a safe, yet effective solution...

 

[Hit The Road Jack]

Were did you purchase the resonator? TIA

David

See my post above...second to OP...

 

[aljimenez]

IMHO, you've cut down the life expectancy of the 'No-Ran' considerably......If the manufacturer felt trapping excessive heat with thermal blankets in lieu of limiting sound was acceptable, they'd have installed sound deadening material under the generators shroud...

If you look into the Onan generator's option, they offer a sound insulated option to the compartments that some RV's have their generator's installed. The PW's generator is not even in a compartment, so IMHO the sound insulation out in the open has little to do with how long a generator that runs infrequently will last... Al

 

[mike_mcginn]

Were did you purchase the resonator? TIA

David

I ordered it from Dyers Online per Hit The Road Jack's
post above.

I also ordered the tailpipe. Didn't know if my muffler guy
would use it or not. Worked out he did. It also included
a hanger bracket. He threw that away and used a piece
of tire with the hanger bracket. Said it would last much
longer. (my original equipment hanger had worn thru.)
What pushed me over the edge to finally invest in the
muffler was the fact I had a blow out that tore off the
existing tailpipe so a repair was coming anyway.
I did not realize the tailpipe was gone till the detectors
went off. At least now I know they really work.

 

[AGP]

This is all relative and how you use your genny. Mine is 2.4 LP and on the noisy side. My use is usually in roadside rest stops or truckstops and can be from 15 min for the microwave to all night to run the a/c if really really hot.

What i love about it is it drowns out the diesel trucks and lately refer units. Sometimes these puppies are less than a foot away, so my little onan just drowns them out. Hell, I even had a trucker on idle move because we were so noisy. I put in my earplugs and sleep like a baby.

One mans problem is anothers solution...

 

[Trekker]

If you look into the Onan generator's option, they offer a sound insulated option to the compartments that some RV's have their generator's installed. The PW's generator is not even in a compartment, so IMHO the sound insulation out in the open has little to do with how long a generator that runs infrequently will last... Al

Both views have merit. To help me in deciding, how long has your insulation been in place, Al? I don't use mine for extended periods either, and although I tend to agree that excess heat could damage the unit, we can only guess as to the magnitude of the the effect.

 

[aljimenez]

Since Summer of '07
Al

 

[jackfish]

Regarding the second post, I think it is widely accepted that an increase of 10dB SPL is perceived to be approximately twice as loud. But you are quite right about increases being logarithmic. An increase of 20dB SPL would be perceived as four times as loud and a 40dB gain would seem 16 times as loud. Hearing tests with large groups of people have revealed that a 1-2 dB change in loudness is approximately the smallest audible step that the average listener can detect, so an increase of 3 dB to most listeners is usually considered "slightly louder."

It looks like the resonator alone will get one well below the NPS standard and save a couple hundred bucks. 62dB at 23 feet is likely only slightly louder than normal conversation in close proximity.