Hate to derail a thread,
You mean because you originally put this in Mani's topic ?
Yep, good thing.
The ear uses pressure as the reference to detect loudness, non-linearities in the bass cause the perceived loudness and false bass perception.
It is not as easy as this I think.
OK, nobody is going to read this :
http://www.google.com/url?q=http%3A%2F%2Fwww.davidgriesinger.com%2Fasa05.pdf&sa=D&sntz=1&usg=AFQjCNEYYTc4mRmxDYz2uXlrSpYoJJCnQA... but I know you already did VJ. So ... interesting.
But to me almost all in this article looks wrong, starts at the wrong angle, uses the wrong solutions which are impossible anyway, but STILL indicate the base problem (like in your quote) which also could be wrong-ish.
First this :
When a low frequeny wave is modulated by its own distortion (or other higher frequencies for that matter), there's less "individual" SPL changes. And, when a single nice undistorted frequency is there, there's clear SPL change per cycle.
This is just so you know, and might you have bought that SPL meter I 'd advise everyone (but especially MKII owners) then you can easily see it.
Side note : Loudspeakers will not create a general pressure change in the room (although closed cabinets to some extend will (DC offset like) but possibly so minor that it can't be measured. So the SPL as such is a continuous change of air pressure which average out after one cycle to normal air pressure.
It is important to understand this, because that article suggests nothing about that while it is ALL about that. So this is nothing about initial responses ... it is there all the time. I can hear it totally easily, just as my SPL meter shows it (the lower the frequency the more easily visible).
Because this is physically so, it also is so that we human can perceive it. But of course, first find the music which shows it, which starts with the undistorted sine or almost sine or modulated which so much higher fruquencies that the SPL changes keep in good shape.
So yes, I am ignorant as hell as usual, but I guess that happens when empirical finding is mapped on to so called science, but where science uses the wrong "material" to begin with.
Remember, I do not suffer from standing waves the slightest, so now that article can go into the trashbin for that reason alone.
Intermezzo :
When Paul (scroobius) was here the other day, we discussed the directivity of bass. Of course from our (his) known perceptions that was and it was just a subject during a glass of beer. But Paul was so wrong (the world is so wrong) and I showed him with an album he owns himself. I pointed out in advance that we should not listen to the metal of the upright bass which is fooling and that the focus should be on the sustained low frequency (what is that ? 38Hz or so) and when the sound is not too square because that too implies higher frequencies which are easy for us humans (for localization).
Of course Paul was floored instantly.
Since the above is the real truth the whole of the article is not and the conclusions of it (by a reader like us) are also moot.
What the writer tries to do is implying localization by false means (uhh, what I *hate* all that !) while all is already working in the first place. But use some proper gear.
Of course the article isn't the subject, but the (wrong) conclusions of it is. What sure *IS* true though is that room modes can f*ck up. So of from there canecellation (but also a kind of warbling tone distortion) emerges, then yes. But it is still not related to our incapability of of perceiving the lower frequencies because they can only go by SPL changes. Thos changes are physically there at continuous tone and I not only can easily "hear" them ... if someone does not hear them he is deaf.
Moral : Sort out the room when not perceived. And this is not done by positioning speakers asymmetrical.
Btw notice that we tend to let blend the sound - but now low frequencies by toeing in. So a sort of exagerrated toeing out can already help. This can be perceived as "oh, but now left and right for bass does not blend !". Yeah ? well, if that happens this is because it IS not firing at the exact same time. So that too, to my humble opinion, is not to be solved by deliberately "mix" the both to one LF mush.
Side note again :
I was experimenting with someone the other day who suffered from some strange sensation (I use the medical term now, so negative) which clearly could be dedicated to the SPL hammering all the time. Think 32 times etc. per second. Toeing in removed the sensation plus some perceived "hole" in the middle was removed.
But this tells all, right ?
Summarized :
I am ignorant, yes, but all I do is judge reality. It is important because might science think we can only perceive the initial SPL change (or attack or how to call that thing which does not even exist) then I tell science this is not right.
What also won't be right is that such bass is more light BUT BUT BUT I now talk about the undistorted bass which is not modulated to begin with. This means : listen to the music which can do it, or, music which contains the lower frequencies to begin with (both are not the same). And this I told about before : this takes really really much experience and I too learn more of it each day (play more new music that means).
I say it again : feel your woofers. You will be able to tell easily (if you start doing this regularly) which music does it and which does not. Still, both types may audibly be perceived the same which means that your room is the issue.
If you feel nothing there is nothing. If you feel excursion of ~3-4mm both ways, your bass will exhibit something like 90dBSPL. If you don't hear that at the listening position, something is not right.
Get that (Radioshack) SPL meter. You'll learn so much from it.
Peter
PS: VJ, this is unrelated to your post, but I am just thinking about it : When you put the speakers to the wall opposite of the TV you will "enable" longer waves because now they can go upstairs so to speak. This is not symmetrical of course, but I think it can do a few things.
