On Wed, Jan 15, 2025 at 01:54 PM, Chris wrote:
so I would like to play it safe and go on the larger side for the baffle throat as I can always make it smaller by reducing the opening
In terms of sound muffling performance, there's almost no reason that you'd benefit from later making the baffle cross section smaller.? The only time that pays off is when the cross section is large in relationship to the baffle length, and so sound is able to pass through the baffle without bouncing around much.
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Also, keep in mind that I'm giving advice aimed at making really big reductions in the sound level of the dust collector.? But you shouldn't lose sight of the other noise sources in a typical workshop, and there's no point in pushing the sound level of the dust collector beneath the "noise floor" created by other sources of sound.? Particularly if you have a dust collector that's automatically switched on/off when you turn tools on/off, you just need to make the collector quieter than the tools you're running.? Laguna rates this collector at 88 dB.? If you're only triggering it when you're operating a tool that produces 70 dB noise, than a 20 dB reduction in dust collector noise will probably make you happy.? I'm glossing over the details of different noise levels at different frequencies.? But even considering that, you'll probably be pretty satisfied with even a 30 dB reduction.
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To give an example, I first started building "hush boxes" for generators to quiet down camping trips I take with a big group of friends (Burning Man).? A single wall hushbox constructed of 3/4" ply with an internal lining of 4" wedge acoustic foam perpendicular to the exhaust airflow and a 90 degree bend in the exhaust path is enough to make a muffled Honda generator quiet enough that people are happy to sleep next to it in a tent (i.e. no additional sound isolation) without complaint.
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-Michael Wolf
Tahoe City, CA
