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

[Timatuu]

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:
Multi frequency Helmholtz Resonators, similar to the design described in this publication: MDPI Materials, Multifrequency Helmholtz Resonator(

https://www.mdpi.com/1996-1944/15/18/6450

.)
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.

 

[highfigh]

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:
Multi frequency Helmholtz Resonators, similar to the design described in this publication: MDPI Materials, Multifrequency Helmholtz Resonator.
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.

Good info, but what is the application? Recording, testing, production of sensitive materials....

If you're trying todeal with infrasonic energy from outside of a building, move to a location where it's not a problem.

 

[Timatuu]

Good info, but what is the application? Recording, testing, production of sensitive materials....

If you're trying todeal with infrasonic energy from outside of a building, move to a location where it's not a problem.

Hi, fair question.

This is for a personal research project in a small indoor space (~X m³). The aim is to reduce low-frequency noise (including infrasound) to a level where it’s no longer perceptible or disruptive. I’m not in a recording or manufacturing environment, it’s more about controlled listening/quiet conditions and studying perception thresholds.

Relocation unfortunately isn’t an option, so I’m looking at what can be done within the existing space. I’m open to a mix of approaches, passive tuned resonators for the more stationary frequency components, and active cancellation for the really low, narrow-band parts.

If you’ve worked with low-frequency control before, I’d be interested to hear:

• Which passive methods are most effective for sub-100 Hz, especially in small spaces.
• How practical it is to combine stagger-tuned HRs to cover a wider band without eating up the whole room.
• Any pitfalls you’ve seen with ANC systems at infrasonic frequencies.

Thanks again for taking the time to ask, I know this isn’t the most common problem, so any insight is a big help.

 

[ski2xblack]

The audiology lab at one of the hospitals I worked at didn't use any gimmicks, just appropriate construction and insulation. That was a quarter mile from I-25 in urban Denver, and absolutely nothing got in. I suspect that approach would be more effective than what you propose. Helmholz resonators or active noise cancellation (if you could even pull off such a feat) would work for sound propagating in the air, but infrasonics go through structures.

 

[TLS Guy]

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:
Multi frequency Helmholtz Resonators, similar to the design described in this publication: MDPI Materials, Multifrequency Helmholtz Resonator(

https://www.mdpi.com/1996-1944/15/18/6450

.)
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.

Your plan is a complete waste of time money and effort. It is doomed to failure.

The only viable approach is to stop the sound getting in. Ideally an anechoic chamber, but inter door locks and heavy sound deadening and adsorption on all surfaces is the way to go. In any event creating this space will not come cheap, so I hope what you are trying to do is worth it. However, I think I sniff a "pipedream".

 

[WaynePflughaupt]

Hi, fair question.

This is for a personal research project in a small indoor space (~X m³). The aim is to reduce low-frequency noise (including infrasound) to a level where it’s no longer perceptible or disruptive. I’m not in a recording or manufacturing environment, it’s more about controlled listening/quiet conditions and studying perception thresholds.

What is the purpose? Is it just an experiment? Is there low-freq noise outside the building you’d like to reduce in your room? Or are you trying to prevent a subwoofer in the room from bothering neighboring rooms or apt. units?

Regards,
Wayne A. Pflughaupt