Today's Message Index:
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1. 05:18 AM - Re: the Obsidian Files - So Much Noise!!! (Area-51)
2. 05:32 AM - Re: Re: the Obsidian Files - So Much Noise!!! (Pete Zut)
3. 03:12 PM - Re: the Obsidian Files - So Much Noise!!! (Area-51)
Message 1
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| Subject: | Re: the Obsidian Files - So Much Noise!!! |
An update on yesterday's recon into an exhaust muffler... spent the day trying
a few different things mods; all that was mostly achieved was a transposition
along the frequency band but not much db reduction... gave up for now and went
back to testing the carbi box... and...
Well as expected 181's stock factory air box did pretty much zip to shut things
up; on average about 3db across the whole range. Then the Mod box got some scrutiny.
Mod box rocks... on average around 25db to 40db reduction through the target range;
WOT rpm primary frequencies are returning up around 30db and secondary harmonic
ranges are returning around 15db reduction.
Will have to build this Mod box and see if the actuals match!
A 25db noise reduction from the engine will make eating cheese inflight more enjoyable
again.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510554#510554
Attachments:
http://forums.matronics.com//files/4541ab07_5f7e_46ca_bbdf_81db650db7be_323.jpeg
http://forums.matronics.com//files/4a5b083a_2868_4a19_87ec_52ec2fb91a84_865.jpeg
http://forums.matronics.com//files/24cfd4c9_e4c0_4e33_a6fa_51941a51b4ae_144.jpeg
http://forums.matronics.com//files/21aad5b2_293e_406a_9d29_95687c07c806_189.jpeg
Message 2
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| Subject: | Re: the Obsidian Files - So Much Noise!!! |
question: the mod is an additional resonating structure installed within
the stock box?
thx,
PeteZ
On Thu, Mar 30, 2023 at 8:25=AFAM Area-51 <goldsteinindustrial@gmail.
com>
wrote:
> goldsteinindustrial@gmail.com>
>
> An update on yesterday's recon into an exhaust muffler... spent the day
> trying a few different things mods; all that was mostly achieved was a
> transposition along the frequency band but not much db reduction... gave
up
> for now and went back to testing the carbi box... and...
>
> Well as expected 181's stock factory air box did pretty much zip to shut
> things up; on average about 3db across the whole range. Then the Mod box
> got some scrutiny.
>
> Mod box rocks... on average around 25db to 40db reduction through the
> target range; WOT rpm primary frequencies are returning up around 30db an
d
> secondary harmonic ranges are returning around 15db reduction.
>
> Will have to build this Mod box and see if the actuals match!
>
> A 25db noise reduction from the engine will make eating cheese inflight
> more enjoyable again.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=510554#510554
>
>
> Attachments:
>
>
> http://forums.matronics.com//files/4541ab07_5f7e_46ca_bbdf_81db650db7be_3
23.jpeg
>
> http://forums.matronics.com//files/4a5b083a_2868_4a19_87ec_52ec2fb91a84_8
65.jpeg
>
> http://forums.matronics.com//files/24cfd4c9_e4c0_4e33_a6fa_51941a51b4ae_1
44.jpeg
>
> http://forums.matronics.com//files/21aad5b2_293e_406a_9d29_95687c07c806_1
89.jpeg
>
>
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Message 3
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| Subject: | Re: the Obsidian Files - So Much Noise!!! |
Correct.
Grafted component, either 3D print or dissolvable Styrofoam plug with fibreglass
skin
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510558#510558
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