Aesthetix Io Sig vs Manley Steelhead-opinions pls

I think you might be pushing the analogy a little too far. :^)

The point is that the white space between the brush strokes is as important as the brush strokes themselves to the aesthetic appeal of the overall painting.
For me, the 'empty' space between the sound of the images on the soundstage is as important as the sound of the images themselves to the aesthetic appeal of the overall presentation.

Here is a case in point: I can set the VTA and VTF on my arm such that my system can present a near perfect holographic reproduction of a violin. I can also alter the VTA and VTF such that the image of the violin is not nearly as distinct but now I can 'see' the violinist, the expression on her face, and the room she is playing in. Most visitors are more impressed by the former but I prefer the latter.

I think I do know what you mean; it's one thing that vinyl definitely does "better" than digital, in that the silence on vinyl sounds more real (to me, anyway).

An interesting off-topic here. I can relate as I often associate digital sources resulting in more immediate truncation of the notes. Does this result in more "observed" silence between the notes from the digital source? ..... because the notes exhibited by the analog source carry on a bit longer? I also find this longer-note-follow-through portrayed by the Aesthetix Io and Callisto more than other phono and line stages I have heard in my system. It will be interesting to hear how the Aria WV performs in this key area.

Vinyl definitely does it better than digital and I agree that Aesthetix does it better than any preamp I've heard.
I sometimes wonder about the "black backgrounds" and "silence" that people get excited about, especially when they insert new digital, new cables, or new power conditioning into their systems. I have heard some very expensive products which provide silent, 'black backgrounds.' The background is certainly free of ambient detail, note decays, action (the projection of sound from images towards the listener) and spatial information.
I won't name names so as not to offend.

Not all trailing-edge transiency is equal. Listen for a component's ability to reproduce human intervention on decay. Perhaps most audibly evident from percussionists dampening their instrument (timps, bass drums, cymbals, bells,) with their hands. Conductors and concert musicians are aware of decay and actively manage it. Its pretty cool. That big dynamic full stop that leaves an harmonic cloud sprayed over the entire orchestra - that wonderful moment when the air is charged, when some are sated and some are stunned and no one is yet applauding. Or the flickering fade from the single emberesque note at the top end. Bow no longer touching string, asymptotic, the lark ascending.

And yep - some cables with their bloodless black backgrounds sucking on the event horizon only to offer hyped hi-fi artificiality that screams digititus. Point my ear at a real world black background - pretty rare if you ask me.

Tim