I accidentally did an unsighted cable test once for a group. Hosted a group from Texas Bottlehead. Wanted to show off my self modified Marantz SA-8260 disc player.
There was a selection of equipment brought by attendees. After a few hours I hooked up my stock 8260. Played a couple tracks.
Went to swap out with the unit with lots of parts swapped out. Someone had brought an AR brand interconnect, To demonstrate how this 15 - 20 USD interconnect was as good as needed. Used it.
Hooked up modified player, grabbed one of my homemade cables with 26ga solid core 6/9 wire, cotton dielectric insulation, and original Eichmann Bullet Plug RCA connectors.
Played the same tracks. The audience (20 people really into sound) all said my modified 8260 was several levels about the stock player. Sounded like a 10,000.00 Playback Designs or Meitner disc player. Did sound like a different animal.
Decided to swap out to allow someone with a 80.00 modified DVD player to hook up for the group to hear. Group asked if digital output from Marantz disc spinner could be used to feed to cheap DVD player My modified unit had a plug on digital output to terminate at 50 ohms.
When I went to remove, saw there was none. Somehow when swapping between 8260’s the stock unit was removed and put back in. We had listened to the stock unit twice.
The difference in playback was all generated from replacing the AR branded RCA cables with the homemade cabling.
Later I tried a gimme cable back upstairs in my system. The difference I heard from cable swap was huge. My modified SA-8260 was almost identical to the stock unit. All the capacitors, bypasses, physical dampening, clock change, and digital output termination made almost no difference.
For those who some who think either everything makes a difference AND the group who think nothing makes a difference, maybe an unsighted test is needed.
Many items do not make any difference. Some items do make a difference. We just need to listen to hear them. Not dismiss automatically.
I think RCA connector transmission is flawed. Both analog and digital. I was using Amphenol TWINAXIAL BNC connectors when building my own gear. BW is 4Ghz. Could go SE or balanced. True pieces of art in construction.
I think the superiority of proper XLR cables levels the playing field. When connected as designed the connector and cabling used are not really audible. Maybe measurable.