This might cause infrasound? - Page 1
Forum section: electronics / beginners

author: MartinSalvador1
author_rank: Contributor
timestamp: December 16, 2024, 10:26:54 pm
content: Last year a really big commercial Hvac was installed below my apartment to supply a medium-large shop, since then there has been a pressure in my ears, specially in my bedroom, which is above the hvac. I can hear a low pitched hum, (probably 40-50hz at 30db) even with everything closed but i dont think thats the culprit.( I think the hvac might be also producing infrasound at way higher levels). Other neighbours have this same problem aswell and i have been told it might be infrasound as the hvac might be bad calibrated (i experience vibrations in my beedroom which is in a 4th floor) so my question is, could this acctually be infrasound? And if so how much could this hvac be producing? Thanks in regards and excuse my English

author: SteveThackery
author_rank: Super Contributor
timestamp: December 17, 2024, 12:07:57 am
content: My experience of infrasound is not a constant pressure in my ears, but rather a pulsating pressure at the frequency of the sound. Pulsating isn't the right word: I mean the pressure "feels" sinusoidal (that is, without any audible harmonics).

author: jpanhalt
author_rank: Super Contributor
timestamp: December 17, 2024, 12:24:30 am
content: I suspect you have read up on such low-frequency sounds. Wind turbines can produce them too. There are lots of studies. Some people are more affected than others. I am one of the affected ones and had the same problem with a HVAC system over my office once. Nice office, but intolerable for me to work in. I'd go the the main cafeteria when I needed to write something.Here' a somewhat sensationalized story about Taos, Colorado:https://bigthink.com/culture-religion/this-mysterious-sound-drives-some-to-insanity-suicide/Considering what you describe, your best solution is to move. Sound insulation will not be very effective .

author: Konkedout
author_rank: Frequent Contributor
timestamp: December 17, 2024, 03:21:58 am
content: Sort of a techie solution...but some sort of sound cancellation might be worth a try?Low frequency microphone in one place, audio amplifier and a large subwoofer (transducer) directed to your head. It might be worth looking into. The phasing would need to be adjusted somehow.

author: CaptDon
author_rank: Super Contributor
timestamp: December 17, 2024, 03:27:33 am
content: The new HVAC is below your apartment but your bedroom is below the HVAC? how possible?

author: CaptDon
author_rank: Super Contributor
timestamp: December 17, 2024, 03:30:44 am
content: You "Can hear a low pitched hum (30dB)" Did you mean 30Hz??

author: CatalinaWOW
author_rank: Super Contributor
timestamp: December 17, 2024, 03:50:28 am
content: I suspect most people are sensitive to infrasound at some level. One of my vehicles acts as a big low frequency whistle at most road speeds when just one rear window is opened. It is hard to describe the effect, a whump-whump-whump is the best way I can describe it. It doesn't really register as a sound and I am not at all sure that the ears are the "transducer" involved. Best estimate of the frequency is 10 Hz, but error bars are probably 5 Hz.It is unbearable for most if not all people I have had in the car with me (me too) but is also very high amplitude. Lower levels probably don't affect everyone.There is no simple and practical way to shield such frequencies, it is hard to wear headphones with resonators larger than your head. The only real solution is to kill it at the source, which means convincing the building owners there is a problem. Measurements as suggested above are one of the pieces of evidence that will be needed.I would be cautious about suggesting balancing the system as a solution. The only thing I have heard described in balancing an HVAC system is assuring that proper flow occurs in all the ducts. While some practitioners may look for resonant behaviors and attempt to correct them I suspect many won't. And the owners won't warm to you if they pay for a service activity and it has no impact on your problem.

author: Konkedout
author_rank: Frequent Contributor
timestamp: December 17, 2024, 05:14:29 am
content: Yeah I was also wondering about "above" and "below." But I think that cancellation has more potential for low frequencies, while insulation has more potential for high frequencies.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 17, 2024, 09:27:29 am
content: I tried Bose noise cancelling headphones, and they didn't help. That was the version they had 20 years ago. It's not just hearing. It's an apartment with a commercial shop. I suspect the owner would elect to keep the shop and lose some renters rather than the other way around.The only sure remedy is to move.

author: SteveThackery
author_rank: Super Contributor
timestamp: December 17, 2024, 01:28:18 pm
content: Quote from: CaptDon on December 17, 2024, 03:30:44 amIt's also worth pointing out that 30Hz is by no means infrasound and is clearly audible as a tone. Church organs will often go almost an octave lower than that (down to 16.35Hz), although that is obviously outside the oft-quoted 20Hz-20kHz hearing range.

author: CaptDon
author_rank: Super Contributor
timestamp: December 17, 2024, 09:15:45 pm
content: His statement "I can hear a low pitched hum (30dB)" indeed is contradictory in itself. As Steve points out 30Hz is not down in the infrasound range but describing it as a hum would suit 30Hz. If the O.P. wants to walk in dB land then it would make more sense to say "I can hear a low pitched hum that measures 30dB SPL using the 'A weighted' setting". About 99% of sound pressure level meters won't respond to infrasound since it is well below the cutoff of the sensing device (microphone) although there are devices made to specifically respond to atmospheric pressure changes occurring at the infrasound rate. Infrasound would be more like a low or slow rumble, flutter or maybe flexing felt in a wall or window like when a Huey UH-1 helicopter is approaching but still 2 miles away or as a wind turbine blade passes the pressure zone where the individual blade is parallel to the vertical support structure.

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:22:42 am
content: Quote from: SteveThackery on December 17, 2024, 12:07:57 amWell, for me its kind of a constant pressure specially in my right ear, but it variates depending on the room im in, also im getting diziness, constant headache and some other sort of symptoms

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:27:20 am
content: Quote from: jpanhalt on December 17, 2024, 12:24:30 amWere the symptoms gone when you left the office? Or was it better when you left the office but you kept having them to a lesser extent?

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:29:45 am
content: Quote from: CaptDon on December 17, 2024, 03:27:33 amThe bedroom is obviusly above the hvac aswell, thats a mistake i made as i was making this post in a rush, apologies for the confusion, its fixed now

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:31:10 am
content: Quote from: CaptDon on December 17, 2024, 03:30:44 amNo, i can hear a low pitched hum of about 40db or something , but i suspect the hvac might be producing a way higher intensity infrasound aswell that could be the culprit of my symptoms

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:35:37 am
content: Quote from: CatalinaWOW on December 17, 2024, 03:50:28 amIm planning on buying a infrasound sensor to try to figure out the intensity of the infrasound im exposed to as i have ruled out every other posible common explanation, but im afraid they wont do nothing even if i find and can prove high levels of infrasound since its not audible sound.

author: MartinSalvador1
author_rank: Contributor
timestamp: December 18, 2024, 01:41:10 am
content: Quote from: CaptDon on December 17, 2024, 09:15:45 pmSorry if my text was confusing in any way, as English is not my first language i actually messured the sound with a mobile app(althrough im sure those are not very realiable) and it was something between 40hz to 50hz with a 30db spl Intensity, however i think the hvac is actually making a way higher intensity infrasound aswell, as my room is vibrating sometimes and i dont think the audible sound i mentioned before could cause my symptoms in any way, apologies for any confusion

author: jpanhalt
author_rank: Super Contributor
timestamp: December 18, 2024, 03:15:35 am
content: Symptoms were definitely gone when I left the office. That's why I worked in the cafeteria or other rooms and only used the office for meetings.

author: jpanhalt
author_rank: Super Contributor
timestamp: December 18, 2024, 03:20:25 am
content: Quote from: MartinSalvador1 on December 18, 2024, 01:35:37 amWhy? When you are not there do the symptoms disappear? If so, it is unlikely the owner can or will do anything; although, it might help you get out of a lease.

author: Konkedout
author_rank: Frequent Contributor
timestamp: December 18, 2024, 05:58:55 am
content: Noise cancelling headphones would only cancel the sound pressure at your ears. But a properly set-up microphone and subwoofer may help cancel the sound pressure for your entire body.

author: Berni
author_rank: Super Contributor
timestamp: December 18, 2024, 06:36:53 am
content: Yep this can certainly be a thing.My car also finds a low resonance with the windows slightly down and going a certain speed. It is hard to describe, you can't really hear it like a normal sound, but it is uncomfortable.You will not be able to do noise canceling effectively on this because frequencies this low are VERY hard to reproduce with speakers. You need something like a rotary subwoofer to do that.Hopefully you can get the landlord to get a HVAC technician come look at the issue, it is possible that just some fan settings or baffles need to be adjusted to fix the issue.

author: MartinSalvador1
author_rank: Contributor
timestamp: December 19, 2024, 12:07:26 am
content: Quote from: jpanhalt on December 18, 2024, 03:20:25 amAt this point, its just to be certain, my symptoms dont go away completely if i just leave the apartment but they gradually get better, as far as i have researched there is some kind of restrictions towards infrasound levels in my country, but its usually related to fabrics and industrial enviroments, however im still going to try just in case im right and they can actually do something about it. Thanks for your comment.

author: MartinSalvador1
author_rank: Contributor
timestamp: December 19, 2024, 12:09:46 am
content: Quote from: Konkedout on December 18, 2024, 05:58:55 amI have no knowledge in this matter, but wouldnt be this unpractical?

author: MartinSalvador1
author_rank: Contributor
timestamp: December 19, 2024, 12:13:44 am
content: Quote from: Berni on December 18, 2024, 06:36:53 amThank you for your reply, i still dont think they will do anything about it since its not considered as "audible noise" anyways im still going to try get a infrasound sensor and see if thats the problem behind this.