Originally Posted by MinnesotaGreg
Anyone know the best spot to sit along the frequency wavelength to maximize chest punch? Not sure if what I'm asking is relevant or that I even really understand it but I want to know the best spot to sit from my 4000ULF to give the most chest punch. I heard 50Hz gives chest punch, so if a 50Hz wave is 22.6 feet long what distances are the best to sit and worst? (assuming the sub has to remain at a fixed point in front of the room)
I don't think that's quite the way that chest punch works. To start with, different people feel chest punch at slightly different frequencies. The range from about 50Hz to 80Hz is most common, and there is some evidence that chest punch is strongest for most people in the low-60's. One older study I read several years ago put 63Hz as the average that it found, and some subwoofer makers have preset PEQ at 63Hz.
Second, chest punch, like SPL, seems to decline with distance. So, nearfield subwoofer placement is most likely to increase chest punch, rather than the wavelength distance. Chest punch is a tactile phenomenon, and not an audible one. It is caused by sudden, percussive sounds in about that 50 to 80Hz range, and the range is broader than that for some people. Those percussive sounds involve the physical movement of air particles, and not simply the movement of sound wavelengths through
The air particles are displaced (by both the drivers, and the ports in a ported sub), causing a sympathetic reverberation in the air-filled chest cavity. In order to have that sympathetic reverberation, I believe that we need to have three things: sudden percussive content at about the right frequency (such as the strike of a kick drum or a gunshot); reasonable proximity to the transducers reproducing that content; and sufficient volume to feel the reverberation in our chests. Even then, some people seem much more susceptible to that sensation than others.
One individual may be able to feel the sensation with as little volume as ~80db, where someone else may need volumes well in excess of 100db, so this is something you will need to experiment with for yourself. But, to answer your question, I think that you will probably need to either have your Cap 4000 close to your listening position, or you will need very high volume levels, or both.
I hope this helps! Let me know what you discover.