Trigger Warning: Bunch of subjective descriptions ahead.
I was at a friend's house last week for dinner. The couple had recently bought a used pair of Kef LS50 speakers. I sat in the sweet spot and listened for a while, and the speakers played on during dinner. It was playing an eclectic station with lots of small acoustic music (folk, chamber, etc). When some well recorded vocals would come on and...I can't help myself sometimes...I would listen to the sound of the voice through the speakers and compare it to the sound of my friend's real voices. "What are the fundamental characteristics that seem to distinguish the real voices from the reproduced?." The conclusion I came to was essentially the same thing I usually hear: First there is a sort of electronic edged, hardened character - vocal sibilance having more the impression of "steely" hardness and sharpness or an electronic distortion, rather than the softer breathy quality of real human sibilance. The voice also lacked the density, the sense of "being solid, in the room, moving air with the acoustic power of a real human speaking." It sounded reductive, reduced, squeezed down from the real thing. The voice texture sounded artificial - it didn't have the sound of real organic materials, the "wet damped, fleshy" quality of the real human voice. And the reproduced sound overall, whether for vocals or instruments, had a sort of "canned" quality. A slightly hardened "electronic glaze" separated it from the real acoustic sounds in the room. Almost like all the instruments were encased in amber, lacking the "air" and presence of real sounds in the room. Subtle textures that tell you "this is real" had been glazed over, smoothed away.
As I'm fascinated by real vs reproduced sound, and these comparisons guide my own decisions on what I want from my audio system, I find doing these subjective comparisons fascinating. But, much of that will float like a led balloon in a forum like this. Unless I could talk in terms of scientific evidence for these impressions.
More subjective observations:
I was at a friend's house (audio reviewer) listening to some new equipment. We played a lot of stuff, including many familiar tracks. The sound coming through that system was almost astoundingly vivid, clear and detailed. A trumpet, sax, drum rim shot, etc had a "right there" immediacy and clarity, and the way it was effortless to "hear in to" any mix to exactly how an instrument or voice was processed or treated (reverbs etc) was really something. We also listened to jazz and orchestral pieces.
And yet, while all this was amazing, nothing to my ears sounded truly "right" or natural, as I hear those things in real life. Something was missing which I could only put as 'natural timbral colour.'
I'd liken the experience to seeing an Ansel Adams black and white photo of a symphony orchestra. The photo can be astonishingly detailed. So detailed that every instrument is sharply captured in the photo, allowing you to identify every instrument. Yet it doesn't make that leap to the instruments "looking as they do in real life" because it's all in black and white, missing the color information. It's all "wrong" in that respect. The sound from the system struck me in just the same way: astounding amounts of detail giving me insight in to the recordings, yet timbrally "black and white." When I close my eyes and listen to an acoustic guitar, trumpet or symphony orchestra my mind registers "tonal colors" that just didn't happen when closing my eyes listening to this system. My mind had to constantly work to "color correct" for this.
Whereas: When I came home an listened to many of the same tracks on my system it was like "aaah, yes!" While it didn't have the vividness and clarity of my friend's system, the colour came back on. Acoustic guitar had that recognizable "wooden body warmth" the strings that "rich harmonic sparkle" a trumpet that "brassy golden glow" tonality that the real thing produces in my impression. My brain doesn't have to do this extra work of "color correcting" - things just seem to "sound right."
This is exactly what I worked for in putting together my system and why I find it so satisfying. It's not that it is therefore "accurately reproducing the sound of the instruments as they sounded in front of the microphones" or "indistinguishable from the real thing. But rather, that it has some important characteristics of "timbral rightness" that is consonant with what I hear in the real life counterparts. And that is enough to help me enjoy it more "yes, that IS how a drum snare sounds - that sort of snappy, papery quality - that IS what I love about acoustic guitars coming through," etc.
On perhaps an even more controversial note: the reason that I have, through various trials, stuck with my current tube amplification is that it seems to me to, in my system, nudge the sound slightly more in the direction my brain accepts as "natural, related to real sounds." (All of this is always with the caveat of possible sighted bias/imagination).
Stereo is never truly going to sound real and totally natural. But one of the things I hear in reproduced sound is an artificial "reductive/tight/squeezed" quality. So if you take a typical studio recording of a small group - vocalist, several acoustic instruments (or even some electric),
on an accurate system I can hear the influence of the microphone/mixing/processing on each element. The voice or sax and it's surrounding acoustic has been sort of "formed and squeezed" by the mic pick up pattern and any subsequent processing. Aurally, it's like each element is under it's own different level of gravity deforming their size and the space around them, usually shrinking their presence too. This is one of the
things that cues my brain to how unnatural things sound. Squeezed, tight, hardened, artificially separated from the acoustic space of the room.
But when I use certain tube amplification and tubes, there seems to be a slight "relaxing" of these qualities. Perhaps a bit of defocusing - instrumental edges and their surrounding acoustic seem to enrich, bloom slightly, blur in to other boundaries. This I perceive as sounding less obviously artificial. So a trumpet, center stage, no longer sounds "artificially squeezed and hard" but relaxed, richer and rounder, and it's surrounding acoustic no longer sounds "squeezed hard around it" but it just blends softly in to the rest of the acoustic of the recorded space and that of my room. It now sounds that much more relaxed, like a trumpet just playing in "real space" in front of me. It's not perfectly realistic of course, but it's a significant-to-me step in the direction of sounding more natural and more pleasing in that respect. It reduces the sense of artificiality, of sound squeezed out of speakers vs just appearing in space around the speakers.
All these things seemed like the apparently differences I heard between the tracks on my system vs on my pal's astonishingly vivid but artificial sounding system. (Though this is subjective: I can easily see someone finding my pal's system as more realistic sounding).
As I've said before, as much as I appreciate this forum, this subjective aspect - "how things sound - talking about and describing the subjective impressions we have when listening to a system" - is an important part of the hobby for me (and many others). Similar to foodies discussing and describing the food they are eating (which I enjoy as well). Or how we often try to describe our experience in all human realms. Even if we could reliably correlate all our subjective impressions to objective data that is causing those impressions , there are still the actual subjective impressions to discuss and describe!
In this sense: Subjective impressions and descriptions of sound, as in much of life, aren't necessarily "Anti-scientific" - unless they make claims that contradict current science or engineering knowledge - but being informal they are "Un-scientific." And "un-scientific" inferences can be reasonable - we use them, often successfully, all day long. But that's still enough so that ASR members will have little interest or patience with "mere subjective descriptions." Which makes sense, given this is a forum where people come to discuss claims that, one hopes, have good objective evidence in order to understand audio gear.
But since in any practical sense we can't submit much of our everyday inferences and decisions to scientific controls, I'm fine with going along with and discussing audio in these subjective terms with other audiophiles. Scaling my confidence levels to the type of claim. It's a blast hanging out with my audio pals, discussing the sound we hear.
This is why, aside from enjoying what this forum has to offer, I also often have to turn to other audiophiles or certain subjective reviews to enjoy this aspect of the hobby. If I'm reading a subjective review I know it's not scientific...and in some respects the reviewer could be flat out incorrect in certain claims. But when I see someone who seems to be "hearing and caring about the things I hear and care about in reproduced sound" and putting them in to words - the type of stuff often frowned upon here - I at least have that connection to that audiophile or reviewer. And it has also led me down some very happy paths in terms of audio gear I've really loved.