Ok, finished up with the 16-core pure copper cable for now. (previous post here:
https://www.head-fi.org/threads/7hz-impressions-discussion.932274/post-16716101 )
Very good overall sound: mild, balanced, but tilted a bit towards the lower registers. After doing some A/B comparisons, it seems that some "air" has been taken out of the music. I don't necessarily miss it while listening, and the music does sound sweet with good depth and super tight, strong bass, but once I compare directly to other cables, I notice it. It's like I'm listening to a slight variation on the original music.
Second cable from my recent order is an 8-core KBEAR Rhyme copper/silver mix. All of the details, air, and atmosphere that I was missing from the pure copper cable is reproduced faithfully with the Rhyme. Frankly, I had very low expectations for this cable when I bought it. I just figured it would be an interesting comparison. But it surprised me. At first, it sounded almost too "sharp" and seemed like the details were too forward. But the more I listened, the more I realized that I needed to focus more on the music compared to some other cables. Once I focused, everything just came together. With this cable, the Timeless produce a very wide and deep soundstage with a tremendous amount of separation. In a word, the music "shimmers". Very lifelike sound with good control on the bass. Not quite up to the 16-core copper standard, but definitely solid, and noticeably better control than the 4-core graphene cable.
It's hard to "rank" these cables, because they are so different. And depending on my mood, maybe I don't feel like focusing too hard on the music. In that case, it would be easier to use the 16-core copper because it's sweeter and easier to listen to without worrying about details. But if I want to get lost in the music and hear it come alive, then the Rhyme would be my first choice. It's remarkable just how comprehensively it represents the music, without leaving out anything.
My previous favorite graphene cable has tremendous slam and detail, and it's really fun, but doesn't control the bass as well as either the 16-core or the Rhyme. And while the staging is similar to the Rhyme, the details don't "shimmer" the same way. It's more of a solid, all-around cable with great dynamics. But it's not as lifelike as the Rhyme. And the stock cable just doesn't play in the same league as any of these aftermarket options, so it will stay in the box for a while.