What I'm talking about is, for example, if I put on a pair of headphones, the sound always seems to be have a certain character to it no matter how I EQ it or play with HRTF.
Right now I'm listening to a system from the other room, and it somehow has this realism and presence to it. I can hear all of these details that I wouldn't hear if I put on a set of headphones, and I get the same general effect regardless of how I screw with EQ. Now, if I change the crossover points or move to a different location the sound signature changes, but it is again constant with EQ.
An extreme example that may illustrate what is happening - I have a 12" aluminum cone subwoofer driver with a massive breakup at 2.1khz. If I let it play full-range, it has that same ringing quality at 2k even with a 25dB EQ cut. Only when I LP below 800hz or so does it go away, probably also related to 1k exciting the 2nd harmonic at 2k.
I also have a pair of bullet tweeters that have this swishy quality above 8k and it always seems to be there regardless of how I place them or EQ them. My AMTs have a graininess above 9k that always seems to be there.
So is this a matter of system resonance at certain frequencies, or location cues that are inherent to speaker/listener location that can't be undone with processing (except perhaps for beam steering with multiple drivers)?
What's the deal?
Right now I'm listening to a system from the other room, and it somehow has this realism and presence to it. I can hear all of these details that I wouldn't hear if I put on a set of headphones, and I get the same general effect regardless of how I screw with EQ. Now, if I change the crossover points or move to a different location the sound signature changes, but it is again constant with EQ.
An extreme example that may illustrate what is happening - I have a 12" aluminum cone subwoofer driver with a massive breakup at 2.1khz. If I let it play full-range, it has that same ringing quality at 2k even with a 25dB EQ cut. Only when I LP below 800hz or so does it go away, probably also related to 1k exciting the 2nd harmonic at 2k.
I also have a pair of bullet tweeters that have this swishy quality above 8k and it always seems to be there regardless of how I place them or EQ them. My AMTs have a graininess above 9k that always seems to be there.
So is this a matter of system resonance at certain frequencies, or location cues that are inherent to speaker/listener location that can't be undone with processing (except perhaps for beam steering with multiple drivers)?
What's the deal?
I find that these type of multipart questions that deal with psychoacoustics are difficult to answer. I'll take a stab, but via parsing your lengthy questions and observations into smaller pieces, below.
Additionally, the effects of hearing masking are apparently changed when talking about putting drivers within a centimeter or so of the outer ear--you're moving the drivers into the nearfield and this affects what you hear in terms of "details". There is obviously a lot more to consider than just these effects when discussing headphones and psychoacoustics--these merely are scratching the surface of the problem.
Additionally, the very narrow polar coverage effects of bullet tweeters will accentuate the audibility of this effect if you're on-axis vs. off-axis.
You've also pulled in nearfield acoustic reflections in room when you make these kind of comments. It's not simply a matter of the drivers anymore--but rather how their output is constrained or not while entering the room or listening area (if outside) and nearfield acoustic reflectors/room acoustics.
Chris
There are ear canal effects (near-field pressurization zone) when you put on ear phones that are seldom discussed. Bob Carver once discussed his "6-foot headphones" whereby he was trying to attenuate the eardrum-headphone driver bounce using longer and longer tubes connecting the headphone driver(s) to the ear canals/ear drums. I believe that he gave up due to the unwieldy size and shape he was getting into. I also believe that it is very instructive not to forget this comment by Carver when talking about "the neutrality of headphones". They're not. There are a LOT of people who don't like that answer.
Additionally, the effects of hearing masking are apparently changed when talking about putting drivers within a centimeter or so of the outer ear--you're moving the drivers into the nearfield and this affects what you hear in terms of "details". There is obviously a lot more to consider than just these effects when discussing headphones and psychoacoustics--these merely are scratching the surface of the problem.
Note that delayed reflections in-room increase our perception of acoustic space and our perception of clarity (i.e., a few reflections actually increase clarity rather than degrade it). Near-field reflections are a function of frequency for individual drivers (or driver arrays) and changing the crossover frequencies will also change the output polar field lobing. Remember these psychoacoustic effects and you will begin to start answering your own questions in this area.
There are low-Q resonances that apparently show up with metal cone drivers being used in direct radiating mode (as opposed to horn-loaded), Apparently, in some cases the cones resonances and even break-up modes (which are really two different phenomena) have such low Q excitation modes that you have to move down in frequency pretty far in order to avoid exciting those resonances and their underdamped characteristics (i.e., ringing).
When you get to 6-8 kHz, it becomes more difficult or impossible to hear harmonic distortion, i.e., anything above second harmonic. What you hear is nonlinear effects (that is, sensitive to SPL) that modulate the diaphragm motion back down through to audible frequencies--sort of like aliasing in digital sampling--except that it is sub-harmonic excitation of the diaphragm and associated horn structures, along with the non-cancelling behavior of the phase plug shape that brings all those modulation distortions out of the horn--to your listening pleasure.
Additionally, the very narrow polar coverage effects of bullet tweeters will accentuate the audibility of this effect if you're on-axis vs. off-axis.
Now you've pulled in "baffle edge diffraction" effects of direct radiating loudspeakers (i.e., those loudspeaker assemblies that do not control their output polars to less than 180 degrees (or greater) of coverage vs. frequency.
You've also pulled in nearfield acoustic reflections in room when you make these kind of comments. It's not simply a matter of the drivers anymore--but rather how their output is constrained or not while entering the room or listening area (if outside) and nearfield acoustic reflectors/room acoustics.
As you can see, there are many "deals" that you are referring to--not just something that you can hang on individual drivers or electrical crossover filters, etc.
Chris
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