Effect of Internet Service Quality on Streaming?

I once had a modest system that would pick up noise and talking whenever a local radio operator was active and even do so at lower volume when the system was off! You might ask your neighbors about HAM radios or look for towers, and try some shielding on your speaker cables. An oscope might help in determining if it’s power or RF. Just use a short wire as an antenna for RF. I'm really looking forward to your impressions of all the NA stuff, esp the Tempus.

It is hard thing to A/B test.  I am not about to rip out my cabling that runs in walls and drop ceilings and replace it with newer digital cables and then go back again, and even expect that an aural memory from one listen to another is reliable.  I did some testing between bog standard cat 5 and the most expensive alternative at the time, by running wires directly from the router to the streamer of the day and couldn’t perceive any difference.  I split the difference and bought something costing in between just in case I was wrong but I’ve been happy with the results.

  I also tried a fancier router and didn’t perceive any improvement.  Recently ATT changed us to fiber and again I don’t detect any difference.

YMMV.  I would just comment that if your system is so fine tuned that changes in digital cables can sound very significant, then I congratulate you on the excellence of your gear

@nagel You are right that the problem you had would be caused by a rogue radio, CB, or ham operator (in my day, when the FCC would actually be chasing these guys down they'd operate out of a mobile location (n.e. car/van) to stay ahead of them).

The problem you had is called "rf rectification".  Simply, what you heard was a subharmonic of the RF signal that a non-shielded electronics is picking up and "translating". Shielding speaker wires will get you nothing as it's actually a bi-product of incorrectly or insufficiently shielded electronics.

Although I haven't run into this is a long time the cure used to be putting aluminum foil around the receiver, installing a numetal shield, or replacing the piece of electronics.  

@nyev   May I recommend any of the harmonic AC conditioners / resonators from Coherence Systems. Their brand is ADD Powr. They work quite well especially for systems with bad power. The Sorcer Apprentice will revive the life in your system. It is a good value of price vs. performance.

Also, for usb ethernet, hdmi digital signal boost the Symphony I/O is a no brainer. It restores the harmonic integrity to your system. They give you 30 days to try anything so you have nothin to lose.

I stream over a T-Mobile unlimited data plan and it works just fine. There’s some startup latency but once the track commences there’s very rarely any interruption.

Sound quality versus file playback from a network HD is quite close. I use a dCS Rossini Player/DAC with clock. The unit seems impervious to tweaks upstream such as using fiber connectors, Ethernet filters, etc. It just works well without any fuss. I don’t have an answer as to why the sound of the OPs system is flat at certain times of the day, my understanding is that streaming services are sending packets of data that either arrive intact or don’t arrive at all, so they’re benign when it comes to issues of sound quality?