Effect of Internet Service Quality on Streaming?

Lots of good recommendations !  I had issues with streaming music versus the EXACT same album loaded on my Innuos ZENith MK3 with a Phoenix USB re-clocker.  I use Qobuz which in my listening opinion sounds slightly better than Tidal.  No matter what time of day though did streaming sound much better until I added in an Uptone-Audio EtherREGEN device between my Ethernet modem and the ZENith.  Finally the music streamed was very close to that loaded onto the ZENith.  I believe re-clocking the Ethernet signal with high-quality clocking and noise isolation from the EtherREGEN made all the difference no matter what time of day. It's the most cost-effective $-for$ I've spent for sonic improvement.  My present cable internet service is ~300mbps.  I will soon be going to fiber-optics with another ISP and their minimum service is ~500mbps.  So, with this change I'll know if anything improves, as I will keep both running and do a direct comparison before cancelling the cable service.  I'll let y'all know what I find !  In my opinion, I don't think for audio you would need any more than what I have presently for internet speed as sonically the streamed music is extremely close (splitting hairs) to that stored on my music server.  

I have recently been through a refresher coarse, so to speak. We had issues with cable TV., so we are streaming TV now. I had previously been streaming over 4 years.  Here are a few items I found out.

-it takes 1Mb to stream music

-each tv uses 25Mb.

-then of course you would have all the others connected to WiFi. Cell phones, laptops, printers.  It is easy to have a dozen items connected

-anything over 108V is considered acceptable to the power utility..  132V is OK on the high side. 

-Noise coming in the line is one thing but wall warts, connections all add EMI/RFI.

-LPS on router/modem. Add a filter to your ethernet line from router to streamer.  You could experiment with some $50 DX Engineering inline filters.  I have a Furman that I plug everything in to.  My accuracy and sound staging took a big step forward after reducing vibration, having good connections and cleaning up noise in the digital domain.

It’s probably some external change since internal changes (audio chain components) do not happen according to the 24 hour clock - worse dinner time then problems ends at the latest midnight.  Therefore the obvious eternal influences are power and internet connection, or somehow EMF/RFI spikes periodically in his living zone.  

Seems the only external influences come from RFI, EMI, power line, internet connection.  If not within the home, then it’s the power line or the internet connection.  Both peak times coincide when people use both more power and personal internet resources, dwindling as people go to bed.  It can also be some business using more resources, like a restaurant, illegal manufacturing lab, Internet cafe.

If it’s the internet connection, then maybe change carriers or change carrier line if possible.

If it’s electrical, then maybe get your power quality tested. For crappy power, Stromtank or solar panels + battery storage system to at least get your system off the grid.  Maybe balanced power conditioner like Equitech o EquiCore might help.  Or a power generator like PS Audio.  Good luck. 
 

Unless you are hearing dropouts, it's definitely not your Internet connection.

I suggest building a dome around your house so you can control light, air pressure, and humidity.  Then your only remaining variable is your mood.  There may be ways to control that too!

Seriously, none of the gear- or connection-based variables being discussed here should have such a dramatic impact on sound.  That's why, while I joke above, I gotta think it's some other external thing - mood, weather, something. 

And I have experienced the phenomena - many people have commented that music sounds best when it is dark out.  I have experienced that too, albeit that also mostly correlates to how much THC I've consumed. 

Occam’s razor time.

@nyev you’ve appear to have spent a lot of money and time on everything but a new router and good Ethernet cable. Dump the router from your ISP as they are worthless. Also, change out whatever Ethernet cable you’re using to Cat-8. As cheap as Cat-6e but super shielded. Check Amazon.

You’ve also mentioned that your problem occurs in the late afternoon, after your kids get home and hit the internet. Sounds like the crappy ISP router can’t take the load and is dropping out (high chance one of your internal connections is bad and causing excessive packet retries which drag down a cheap router). Also the cheap routers don’t have any sizable ring buffers so they can’t queue things up well.

Remember that 4k video requires 34Mb of bandwidth.  Add on whatever else you’ve got streaming (phones (cellular using WiFi and VoIP), internet streamers/radios, television, etc. and you’re probably using 50-74Mb bandwidth easy. Bet the router you have came from when you had 100Mb or less internet.