I thought I would post some information on a wearable subwoofer that can be integrated into headphone listening. I found this when searching for a viable way to produce low frequencies to supplement those already produced by headphones. In my opinion, after switching from speaker-based systems to headphone systems, one of the main deficiencies is bass extension and impact no matter what phones are used. Yes, headphones can produce these low frequencies but not in the visceral way loudspeakers, including subwoofers, produce that pants-flapping, tactile bass feeling. So I have been searching for this type of bass and may have found it.
I have also found through headphone listening that we seem to get two types of mutually exclusive sound signatures. First, like with my Kennerton Gjallarhorn GH50 JME2 phones, you tend to get bass-prominent, slower, warmer, darker sound. Or as with my Kennerton Rognir Planars, faster, detailed, transparent, spacious, treble-prominent sound. But in neither case, that visceral, sock-in-the-gut bass found with some speaker systems.
So you need to have a basic understanding of how bass works. To produce sound in the room it is necessary to propagate sound waves of varying wavelength. Since C=NU where C is the speed of sound, a relative constant 1130 ft/sec that varies slightly with sound pressure, and N is the wavelength of sound and U is the frequency, to get N for varying frequencies of sound we divide C by U. A table of wavelengths for varying frequencies is below.
You can see that the lower the frequency, the longer the wavelength. For low bass frequencies these sound wavelengths propagate for many feet, usually longer than any dimension in our standard listening rooms. Therefore, full-wave theory indicates we cannot produce full bass waves in our rooms and certainly not in small headphone earcups.
So how do speakers and headphones produce bass if the full wavelengths are not found? The answer is complicated (see the link below) but basically bass is produced through air pressurization and de-pressurization. In other words, to produce bass waves it is necessary to propagate air pressure waves. So at the leading edge of the bass pressure wave there is higher pressure in front, and behind it is lower pressure. You all know this by watching a woofer or subwoofer move forward and backward in its attempt to push air forward and backward. This bass pressurization and rarefaction (de-pressurization) is how we produce most bass in small enclosed spaces such as listening rooms, cars, and headphone earcups.
So when we feel bass act upon our bodies in space the nerves (proprioreceptors) in our skin and bones detect this as a bass pressurization wave. Since headphones are covering only a small portion of our bodies, our heads, we don't feel the same bass pressurization effect as we do with a big bass pressure wave pushing on our bodies. How do we get this big pressurization effect on our bodies using headphones? People have tried several solutions.
First, we could add a standard subwoofer localized to our seating position. The problem with this solution is that much of the bass is muffled by the pads on the headphones, reducing its effect. It also may be annoying to others around us.
Second, we can use a pistonic mechanical actuator like the Buttkicker, similar to how movie theaters vibrate chairs in the theater,
www.thebuttkicker.com. This unit is attached to a listening chair or couch and generates low frequency rumble to simulate low bass.
The third way I know is through the use of a wearable pack that uses mechanical actuators to punch your body similarly to how a bass pressure wave would stimulate your skin and bone proprioreceptors and give the sensation of low bass including musical pitch. See
www.subpac.com. These units have been out for a few years now and have been successfully used by movie and record producers, gamers, and music buffs similar to ourselves. There is a new Subpac model coming out later this year, the X1, and I ordered one for myself. Check it out and see if you think it might be the ticket to hearing and feeling real low bass.
I will report when I get mine later this year, hopefully.
BTW, I have no affiliation with any of these companies--I am just a music lover always looking for the most realistic musical event.
https://www.acousticfields.com/wavelengths-in-our-rooms/
