We have been improving (and still are) our vibrations for years now and no other system is close to D-BOX for the quality of the vabrations. The frequency range is absolute theory that doesn't at all affect the quality and varierity of the vibrations we produce. Like I said before, D-box IS the most powerful system on the market. Insted of going higher in the frequency range, we use different wave form that give way more that the 400 Hz difference between 100hz and 500Hz ( I think I know since I use and try vibrotactile vibration all day long and knows how feels a 20Hz, 50 hz and 200 hz as well) . We also use harmonics and unique flavor caracteristic that give a whole new dimension. This is in ANY way more efficient that vibrations so high that are absorbed by any padding.
No matter how you try to spin it, the human tactile system is capable of 500 Hz. I agree it is a challenge to convey very subtle 500 Hz detail with current furniture, however, you must seperate design goals and desires from other issues. It is interesting to speak with various companies and their chief engineers.
I am also familiar with harmics and subharmonics. However, you can not synthesize what the system is not capable of... you are indeed limited to 100 Hz. Ok. Again, I have no doubt that you are doing the best that you can and currently have the best overall system. There is no reason to be defensive. You do have a great product and have pushed the overall envelope further than other company, nonetheless, the overall goals remain the same, difficult to achieve or not.
You also said that padding is another subject, but it actually isn't. You padding is the reason why in theory you would feel vibrations up to 500Hz but you won't. There is no way to feel that in a couch. So it's more of an marketing feature that anything else.
No, I disagree. For instance, Crowson and furniture manufacturers address this issue. It is just physics. you can convey the information, but it is attenuated to a large degree. Personally I have no marketing interest in either company, but the human vibrotactiel system is a whole sense, a whole discrete modality, not some 'condiment' as was stated earlier. I agree it is a challenge to convey this information properly, but that is why we are having this discussion. I do not underestimate the absorption/damping factor of furniture foam, it is a big problem so to speak.
I agree the other challenge is to boost higher frequency tactile to compensate for the sensitivity curve and the damping of the furniture material... Anyway keep up the great work! Maybe you need to start working on the vibrotactile suit...