Sampling Agnetha and Frida's voices

richard , I would welcome it, but with some reservations.

What you're talking about is vocal synthesis - as for "deep, detailed, micro, level" I'll assume you're leaning toward the machine learning side... deepfake, and not the VOCALOID-esque iteration (that one with robotic inflection)

Within today's technology, it has yet to be perfected. It's possible but it'll have to be pushed out of the limitations to get to that.

Machine learning based vocal synthesis is mostly rough, but could be winged out with some fine-tuning, though not convincingly enough so far in this century.

A YouTube channel called Vocal Synthesis has attempted to grab as many vocal samples available to get a profile of Frank Sinatra's voice just to sing a handful of songs he'd be unlikely to sing. (Dancing Queen)

The result is mostly rough; not even fine-tuning by others could save it in this capability.
That channel is also a proof of concept that it could handle conversational voices well (and we'll never run out of Frida and Agnetha saying "Hello California, we're here!" or "Bonjour Paris".)

There's possible scenarios that can reach to the point of uncanny valley. One of them involves a large number of vocal samples (good if it accounts for rising tone, falling tone, speaking Swedish, all of that), a better model built on it, and something groundbreaking yet proprietary (a better learning model or algorithm, I suppose), or the good old reliable open source.

And then you have ethical issues which sent people into a frenzy - for living people, if they were never involved in a project, they'd try to sue their way out, and for deceased people, it gets uncomfortable. If we are proposing that ABBA should engage in sampling voices by means of outsourcing (which they did with ILM for VFX) within whatever time, there should be little to zilch ethical issues for them as long as Frida and Agnetha (or their estates, heaven forbid) consented to it.

Given the abundance of recent internet memes using models of vocal synthesis to make a joke come to life, one would assume that the benefits outweigh the risks. I fall into that camp where indeed it outweighs the risks - as long as there is solution to detect and distinguish synthesized voice from recorded, pure voice.

There's so many debates regarding this, and it's intriguing for a phenomenon that just took off years ago.

I would also like to comment that ABBA or Polar Music would make a smart move to protect their voices, if they do use this vocal synthesis technology. x