1000km at the speed of light is 3.33 ms which on it’s own isn’t an issue. While fiber is slower, you can have low latency connections over that distance without issue.

The real problem is computer audio isn’t designed for low latency. Generally, as long as video and audio are reasonably synchronized nobody notices, but latency as rarely a consideration on it’s own.

This shows actual network latency between regions.

https://www.cloudping.co/grid

Even with the state of the art equipment, transcontinental music making will always exclude the kinds of music that most of us play while in the same room together.

I was specifically mentioning 1,000km as the metric.

AWS latency isn’t great between regions. Looking on some other sites you can see London to NYC is 70ms, but that’s also 5,500km which is far behind the 1,000km mentioned. Ex: https://wondernetwork.com/pings/London

70ms /5.5 = 12.7 ms seconds round trip. The speed of sound is only 1,125 ft/s, and half that for round trips so 1,000km over fiber is the equivalent of ~7.14 feet apart in the same room plus whatever latency your personal computer and software adds.

My DSL line gives me a 20 ms roundtrip to the first hop. My only choices at this address are DSL, LTE (latency seems highly variable, and much more expensive than DSL), or paying at least $50k to get muni fiber installed. So latency will always be an issue here.

Well, I could probably get some form of POTS either analog or ISDN/T1

DSL is pretty much the worst of the wireline services as far as latency goes. Even some of the wireless technologies are better.

If you use sonic, at least in some areas they have a setting where you can turn down the level of forward error correction and get lower latency in exchange for somewhat higher packet loss.