Originally Posted by 3ll3d00d
It might be interesting to see whether the two responses decayed differently. I doubt this makes a difference but might be interesting to check.
The other thought, given the size of the delta between TR at tune and the other frequencies and hence whether 20Hz drowns out the rest, is whether this is, subjectively, a good or bad thing. Answering this would require knowing what "good" TR is though.
Great point about if is a good or a bad thing. The problem is that there is no reference for tactile response. I believe it's possible to create one, but you'll need a sound intensity meter to do so.
What we do know is that ULF is typically under represented from a TR standpoint. How do we know this? The hypothesis is that room gain influences SPL, not PVL. In other words, PVL doesn't have a gain and stays static.
In room this means that it can be perceived as louder (or more pressure) with our ears, but doesn't necessarily produce any more physical tactile response. This is perhaps why single digits in room (which is largely from room gain) doesn't have much of a physical effect other than a weight or pressure.
Here's and example:
Let's assume that thunder has very deep ulf in the 10hz range and it strikes at 115db. When that is recreated via our HT in a room, a lot of the spl is from room gain and thus has minimal pvl and physical effect.
Go outside and experience that same thunder at 10hz at 115db. It will have far more physical impact. There is no room gain outside, and so that sound wave carries a lot of PVL. I think we've all experienced this before.
Also, don't forget that the thunder could have been produced miles away...putting 10hz in the far field. When we are in the far field soundfield, spl and pvl are directly in phase. This means that all one needs to measure is spl to get an understanding of what it should feel like.
And this gets back to my point around finding a reference for tactile response. To get a reference, all frequencies should exist in the far field (outside) without any room gain. Then if you measure with the sound intensity meter, you'll exactly know what 115db at 10hz should feel like...or what a 100db should feel like, etc.