Feasibility and Methods for Attenuating Low-Frequency Noise (0.5–500 Hz)

General Electronics
1

Hi all,

I am exploring methods to significantly attenuate or ideally almost completely eliminate noise within the following frequency ranges:

• 0.5 to 20 Hz

• 25 to 90 Hz

• 100 to 500 Hz

From my current understanding, two main approaches could be considered:

  1. Multi frequency Helmholtz Resonators, similar to the design described in this publication: MDPI Materials, Multifrequency Helmholtz Resonator.
  2. Active Noise Cancellation (ANC) using subwoofer based systems capable of reproducing ultra low frequencies.

Regarding ANC, I am aware of products such as the Eminent Technology TRW 17 rotary subwoofer, which can operate down to 1 Hz. However, this solution is costly. I would like to know whether commissioning a professional to build a similar system together with an appropriate amplifier could be done at a lower cost without compromising reliability.

Alternatively, would it be more effective and practical to implement an array of multi frequency Helmholtz resonators to target these ranges?

My questions are:

• Is it technically possible to achieve full absorption or near complete attenuation of the above frequency ranges?

• If so, what are the most effective methods, whether passive resonators or active ANC, for achieving this goal?

• Are there design or implementation considerations that may make one approach preferable over the other for long term performance?

Any guidance, technical insights, or references to relevant designs would be greatly appreciated.

Thanks, Tim.

2

It sounds like when you say “noise” you mean “acoustic sound” in that frequency range in a closed space like a room? This forum is full of electrical engineers and hobbyists so usually when we think “noise” we think RF and EMI, not sound.

3

We cannot really understand what you’re trying to accomplish from the information given. On top of what @alexw said, the ranges given are strange - you say you want to attenuate 0.5 - 20Hz, 25-90Hz, and 100-500Hz. Does that mean you need to not attenuate 20-25Hz and 90-100Hz?

4

Cascaded switched capacitor filters are worth looking into, though they will need precision oscillators to give really accurate roll-off frequencies.

5

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.