Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: YetiWoodz on 10/12/2019 17:40:06

Title: What is the best material to absorb 4000 hertz frequency?
Post by: YetiWoodz on 10/12/2019 17:40:06
It's not for contruction or room modification purposes. I just want to know the material whether practical or not that is best for sound absorbtion, not sound proofing, of a high frequency of 4000 hz. (chainsaw sound)
Title: Re: What is the best material to absorb 4000 hertz frequency?
Post by: Colin2B on 11/12/2019 12:53:16
It depends on how certain you are about the frequency and the bandwidth. If you have a fairly narrow spectrum you would be better off with a resonator rather than with material.
Title: Re: What is the best material to absorb 4000 hertz frequency?
Post by: alancalverd on 11/12/2019 14:05:08
A reasonably narrow bandwidth can be completely suppressed with an active wall - like noisecancelling headphones but bigger!

Sound insulation is best achieved with a rigid mass like concrete that will reflect the pressure waves. Or a double-wall with a vacuum interspace, though this presents more engineering problems.

Sound absorption requires a soft, high-loss material - a mixture of pebbles (for inertial mass) and Styrofoam beads (for energy dispersal) is worth trying.
Title: Re: What is the best material to absorb 4000 hertz frequency?
Post by: nudephil on 08/01/2020 12:20:50
Some insight from physicist Jess Wade on yesterday's show: https://www.thenakedscientists.com/articles/questions/what-material-best-absorbing-sound
Title: Re: What is the best material to absorb 4000 hertz frequency?
Post by: evan_au on 08/01/2020 20:31:30
Quote from: OP
4000 hz. (chainsaw sound)
A chainsaw produces a very wide range of frequencies.
- Some of it from the chain/teeth biting into the wood
- Some of it from the poor muffler on the 2-stroke motor

It may be easier to put a better muffler on the motor... (but this will make it heavier to carry...)