@ProtegeManiac I will attempt to use more specific terms for what I am really hoping for. I read through the Head-Fi glossary and have collected a few words that pin it down. The audio characteristics I initially described were inaccurate.
I see that my idea of "high-fidelity" is incorrect. It is interesting that that term is not included in the Head-Fi glossary. I spent a lot of time around musicians in recent years. I have not discussed audiophile subjects much at all for much longer than that. I am used to "high-fi" referring to pickups that sound more like a picture of a tone rather than having the spatial presence of being produced by the amp when it is in the immediate vicinity. That concept may not be easily comprehended by everyone. I was also mistakenly under the impression that "high-fidelity" music included the refined colorization of the audiophile systems they are produced and listened with.
Taking that into context, "high fidelity" means "as close as possible to what was recorded." That value of truth is such that infidelity can cost you a lot in the divorce proceedings, or being an infidel can cost you your head in some places. Basically, coloring the sound is no longer "faithful" to the original sound, because you're changing it. It would be like how the people who use the word "infidel" a lot don't like translating certain works from one language.
Basically, high fidelity means "low distortion, low noise playback." And depending on the sensitivity of the speakers or headphones, you'd need an amp that can supply power without piling on distortion and noise, much less clipping.
If anything the reason why people think there is a difference between pro audio and "HiFi" at home is due to a lot of misunderstandings. Some people prefer hi-fi gear thinking that's what instruments sound like, or maybe that's what they do sound like live, except that person doesn't realize that wherever the hell he heard them the venue was coloring the sound more than when it was recorded in a sound dampened studio. This would be like if I demand that my rock albums sound like crap, with drums overwhelming everything and there are barely any vocals, because that's what they sound like in small bars and I'm boozed out of my mind. Except the older folks who do this have some kind of legitimacy when they make Norah Jones sound like she needs to shoot hot chicken soup up her nostrils. Or how they think their Les Pauls and Marshall amp sound better in their garage than the same gear recorded in a well-dampened studio.
Likewise, in some cases some people hear pro gear and tend to think that the relatively lean sound counts for flat sound, when in fact, it can be due to a number of things. Most commonly, studio headphones that have a smooth curve in the midrange for checking the recording but roll off too early at the low end (like a bunch of older AKGs and Sonys). Some Class H pro amplifiers meant to provide a LOT of power with reliability in mind more than super low distortion - just look at the THD % of pro amps at 300watts per channel meant to drive PAs tht have 12in woofers and horns saturating a small auditorium vs Class A home audio amps that make 15watts per channel meant to drive 90dB+ speakers in a small room.
And apart from having no coloration the "picture" of the pickup vs spatial presence aren't necessarily two different things. You can get the tone of the pick up while programming spatial information depending on how the mics and the amp are set up. If anything, electric guitars tend to be recorded like a huge wall spanning the entire length, but in some cases either on the mixer or putting one amp far off to one side (to distinguish the lead on one side from the rhythm doing the Wall of Sound) does put in the spatial information. If that sounds like you're not getting the tone of the guitar well enough, that also has a lot to do with your reference for hearing that tone - standing next to the amp would sound fuller than recording the amp positioned farther out from the middle of two mics.
@ProtegeManiacI would like to hear more form if "form" can be considered an opposite of "flat." Something more articulate, more definition, better imaging, detail, a wider soundstage, more depth, some reviews describe an experience of a particular headphone as "knowing you are wearing headphones" when relating to spatial perception (the "headstage"?)......in this regard I'd like to widen that soundstage without losing the focus of things front and center.........it may not be possible but headphones that sound like you are in the room (large and small) full of musicians on stage performing as opposed to distinct reminders that the sound is coming through headphones.
Again here we have that seeming conflict that isn't. A
flat and wide respoonse
is more articulate and has better definition throughout the range, since you have less auditory masking going on. When you think of them as polar opposites the problem really is you might have as reference studio gear that rolls off early at the bass range and has a spike in the treble (like the K701). This is not the perfect design for monitoring, it was just the best that was available at the time it came out. At the same time you can have something like the HD650 and the non-Fazor LCD-2, which have very smooth graphs if it wasn't for 1000hz and below being considerably stronger than above 1000hz. So on either side of 1000hz they're as smooth as you can get, but having that lower midrange to bass plateau, along with wearing them tight (or several people have already done so before you did at the same show, compressing the earpads too much), you get the sense that they're not articulate because the low end plateau gets boosted even more.
Similarly, in some cases what some people tend to think of as "flat" is just a weak amp distorting or clipping (but not adding noise). For example, a lot of people tend to think Grados are the only headphones that can have a high dynamic range, when in fact the primary factor for that is their high sensitivity. Hook up a headphone many describe as "boring" like the HD650 to an amp like a Meier Classic, Violectric V281, or WooAudio WA3, and you can crank it up to a level where you'd match the Grados' output and without clipping or distorting (or noise masking some of the notes). Ditto using a K702 with the Classic, V281, and the Woo WA6SE (not the same as the WA3, which delivers more power at 300ohms).
As for imaging, you're not supposed to go with coloration either. The more colored the response the more screwed up the imaging gets. Grados are a good example - the boost in the upper bass and lower midrange puts the bass drum forward, the boost in the midrange does the same to the vocals, and the treble boost does the same to the cymbals. Some people feel that sounds "3D," but it's out of proportion - sure, the vocals seem to jump out of the image like a pop-up book, but why would hte bass drum be at the same point on the Z-axis as the vocals? Why would the cymbals be way off to the flanks where the guitars are? No drummer has arms that long, unless Marvel Comics has Reed Richards or Doc Octopus playing drums in a heavy metal band with Thor.
One other barrier is the reality of headphone listening compared to speakers. On the latter the speakers are way out in front of you and each ear hears both speakers. On headphones the transducers are right outside your eardrums, and worse, some headphones just fire into the ear canals at a direct angle, which you may notice is not how speakers are positioned. Some headphones try to remedy one problem with angled earpads or driver mounts, so at least they'd be positioned relative to the ear canals as speakers set to toe-in would be. The hearing problem is dealt with using Crossfeed, which unlike outright Crosstalk applies a filter so that only a given range of frequencies are filtered across both channels and at a set or variable gain depending on the implementation.
So basically, what you need is a headphone that has good spatial performance, an amplifier that can supply more than enough power to destroy your eardrums (not that you'd use all of it) at low THD+N levels, and Crossfeed. Simplest and most direct way to get all these can be a little expensive - Meier Corda DACcord and Classic driving the AKG K702, HiFiMan HE400i, HD800, or HD600 on angled HM5 earpads. I get all that but I do a lot of tweaking - I use an Android phone as a music server so I can run Neutron Music Player, which has variable Crossfeed plus an up to 10-band parametric EQ to help me flatten out the response more, a Pangea HP101 (my old Meier Cantate hasn't been repaired yet, nobody here can figure out what's wrong with it) which has a lot of power for my HD600 headphones, which are also on thick, angled/asymmetrical HM5 earpads.