how important low frecuency sounds are in VR?

[equusvenustas]

Greetings, i been looking the forums since i learnt about the oculus (almost a year), but the news of the acquisition was the drop to overflow the bowl and made me make an account and brainstorm with you nice people, anyway, i have observed that low frequency sounds are somewhat common in the activites we do, from the closing of a door to the sound of an big explosion(not common) and some of the most impressionant nature phenomena also produces low frequency sounds for example a volcano a thunder or an earthquake, sounds below 20Hz have a great impact because you can feel it. and i think they can play an important role in immersion with respect to VR audio, to this date i havent find an earphone able to reproduce low frequency sounds like a subwoofer in a good enclosure, thats one of the reasons i dont like HMD with earphones. So how important do you think is the production of low frequencies in VR.
Tanks for you attention.

P.s. This is my first tread and english isnt my first language so be a little forgiving

[geekmaster]

For subsonics, you need servo drive piston sonic emitters, or variable pitch ducted fan sonic emitters. I should be possible to miniaturize these for headphone use. Not sure if such things are on the market, or how they may be mired in IP brain rape, but should be fine for non-commercial hobbiest use...

However, subsonics should also be felt in the chest as a pressure wave, so a sonic vest may be needed as well.

BTW, a subwoofer IS a servo piston, but a tiny piston used in an R/C aircraft engine piston or something similar may also be used to modulate relatively large air impulses at subsonic frequences. However, I prefer the variable-pitch fan approach IF you can reduce the fan rotation noise that close to your ears. A traditional piston will have less noise and may be easier to implement for a hobbiest.

I would normally google this stuff for you, and provide links here, but I am busy right now. If you really need details, I may supply some later. Meanwhile, see what google can supply you...

[equusvenustas]

hello geekmaster thanks for your response, i have already have done some research about rotary subwoofers but they only seem to work using very big enclosures even the room can be used as enclosure moving the air in and out of the room, so i don't think a rotary subwoofer can be miniaturized to the extent to be wearable also i was thinking how to make a rotary subwoofer using the blades of an RC helicopter but in my country is hard to find RC hobby stores and i am getting good results using normal speakers. I cant say i have made much experimentation in the subject, but using headphones for the normal audio and a cheap 12" subwoofer in a big ported enclosure tuned to 26Hz in a room of 4m by 5m with two beds, playing a record of a thunder in my experience sound very close to the real thing even you can feel it in the chest and if you step in the center of the room you can feel the floor shaking. the tricky part is positioning the subwoofer in the room to avoid standing waves, i got the best results putting it in a corner separated one feet from the walls. i want to share this because to my experience makes an important difference in sound immersion but since i dont have too much experience in VR i am wondering if someone who have experienced VR could tell me how much do you think is going to enhance immersion having that kind of frequencies in VR.

[geekmaster]

I believe you could use a rotary subwoofer (variable-pitch fan) in a headphone enclosure, but it would be difficult to elminate turbine whine that close to the ear, requiring superior acoustic foam insulation AND active noise cancellation, I would think. You do not need a room-size enclosure (mechanical amplifier) to modulate low-frequency pressure waves in an earphone (or rigid chest-plate enclosure). I can envision even ear-bud subsonics (with ear canal pistons), given sufficient research funds. People duct rotary subwoofers into the attic of a house, to get a "room shaking" experience, which is not necessary for personal use (where only each ear and the chest need to be enfolded into the sonic enclosures).

IMHO -- no personal research on this -- just a quick mental exercise based on limited personal knowledge in this area of expertise. My terminology may differ from "common standards" showing my noob status in this field...

I share freely -- please do not patent my ideas, which has happened too many times before. Besides, others probably thought up these things before me, and others before them. We stand on the shoulders of giants. Thanks!