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<blockquote data-quote="Carl Klinkenborg" data-source="post: 218747" data-attributes="member: 12770">Blocking sound and absorbing sound are two very different animals.&nbsp; I think I would be correct in stating that you don&#039;t much care about the sound level within the enclosure, but what escapes it...&nbsp; Whilst absorbing sound makes the room/enclosure itself inherently &#039;dead&#039;,&nbsp; sound level is unlikely to be reduced more than about 4-6dB by absorption alone.&nbsp; Your efforts would probably be better spent in trying to block the (broadband) noise rather than starting with absorption. Wall construction plays a considerably bigger part in blocking noise than does absorption around the source.&nbsp; To a certain extent, mass is king (some of my house walls are 1m thick stone/lime, so I can attest to their effectiveness!)&nbsp; however &#039;lightweight&#039; double-skin walls with absorption inbetween can be very effective.A 10kw generator can range from about 70-90dBA so the scale of the noise reduction required is considerable - do you have specs. on any you are considering?&nbsp; You would need probably 50-odd dB isolation; not that easy in an enclosure which cannot be completely sealed.Helmholtz resonators can be very effective at absorbing sound but have a high Q if undamped, but damping reduces their effectivity.Membrane absorbers could be a consideration, but you would need to know the noise sound spectrum of the generator within the enclosure before you could even begin to address absorptive measures.A further consideration is to isolate generator from the floor slab to reduce ground-borne flanking noise entering your house.Finally, the matter of allowing air in and exhaust/heat out of the enclosure is going to pose considerably more of an acoustic problem than any of the above!&nbsp; Whatever the solution, the open-ended ducting is going to add considerable size to your &quot;(very small) building...&quot;.[ATTACH=full]209922[/ATTACH]</blockquote>

[QUOTE="Carl Klinkenborg, post: 218747, member: 12770"] Blocking sound and absorbing sound are two very different animals. I think I would be correct in stating that you don't much care about the sound level within the enclosure, but what escapes it... Whilst absorbing sound makes the room/enclosure itself inherently 'dead', sound level is unlikely to be reduced more than about 4-6dB by absorption alone. Your efforts would probably be better spent in trying to block the (broadband) noise rather than starting with absorption. Wall construction plays a considerably bigger part in blocking noise than does absorption around the source. To a certain extent, mass is king (some of my house walls are 1m thick stone/lime, so I can attest to their effectiveness!) however 'lightweight' double-skin walls with absorption inbetween can be very effective. A 10kw generator can range from about 70-90dBA so the scale of the noise reduction required is considerable - do you have specs. on any you are considering? You would need probably 50-odd dB isolation; not that easy in an enclosure which cannot be completely sealed. Helmholtz resonators can be very effective at absorbing sound but have a high Q if undamped, but damping reduces their effectivity. Membrane absorbers could be a consideration, but you would need to know the noise sound spectrum of the generator within the enclosure before you could even begin to address absorptive measures. A further consideration is to isolate generator from the floor slab to reduce ground-borne flanking noise entering your house. Finally, the matter of allowing air in and exhaust/heat out of the enclosure is going to pose considerably more of an acoustic problem than any of the above! Whatever the solution, the open-ended ducting is going to add considerable size to your "(very small) building...". [ATTACH type="full" alt="1733998132513.png"]209922[/ATTACH] [/QUOTE]

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