DO CABLES REALLY MATTER?

I became an audiophile before WWII, listening to Victor Red Seal 78s on my parents console using cactus needles. After WWII, I began building and assembling a series of systems, including using the Thiele Small parameters to construct my speaker cabinets. I transitioned from Heathkits to Scott, then quit assembling the components when I got hooked on Macintosh.  I went from 78s to 45s to LPs, to reel-to-reel tape and finally to CDs. Over these years I discovered several truisms with regard to cables:  (a) speakers need the largest diameter cables (12 or 10) terminated with top quality connects. Resistance and impedance should be as low as possible, especially if you have long runs between the amplifier and speakers: (b) Interconnect cables among tuners, CD players, turntables, DACs and preamps need to have shielding, and be terminated with top quality gold plated connectors; (c) cables from the preamp to the amplifier also should be shielded and equipped with top quality connections. I found, through trial and error, that premier Belden cables provided the best interconnects. The trick is to ensure the best connections between the cables and the connectors. 
I found that Blue Jeans Cable could manufacture superb cables, precisely to the lengths I needed, and with the appropriate connectors welded to the wires.  Cost? Not nearly as expensive as many of the highly-advertised products.  IMO, quite a bit of the hype and "reviews" for esoteric cabling is largely snake oil.

To me, speakers - - and their placement - - are really what determine realistic Sound Quality.  Just my thoughts from over 85 years of listening to classical music. YMMV

There are also differences in the monitor speakers or earphones  used in the booth, plus differences in the mixing consoles.

I guess I'm antediluvian. I got my basic training in things dealing with AC current before WWII, as I was a ham radio operator and built my own transmitter/power supply and antennas. I had to sit for an FCC exam to get my operator's ticket. I had courses in both DC and AC  in college BT (before transistors.) 
After WWII, I began to build my playback systems for 45s, LP vinyl, and reel-to-reel. For years, I had access to a fully-equipped shop and constructed my own speaker enclosures using Thiele-Small parameters to assist designing them.
I switched from tubes to solid state when my favorite KT88 tubes ceased to be made in  the US,  and quite "rolling my own."'
During these years I learned that wire gage, wire material, good shielding and properly-connected terminals DID make a difference; however, esoteric cable wire patterns and claims of directional wiring were plainly snake oil.  Cable esistance, capacitance and inductance parameters DO make a difference.
For over fifty years, I've connected my amp to the speakers with 10 gage Belden wiring, and used 14 gage Belden for interconnects. 
Do I have "Brass Ears?" I don't think so'; however, my current collection of  CD classical  symphonies, concertos, chorales, chamber music, requiems, organ music, and operas are most satisfying.
Disclaimer: My system is Bryston preamp, 4Bsst2 amp, Thiele 2.7 speakers with Thiele SS2.2 sub, Bryston BCD-3 CD spinner, Magnum Dynalab FM tuner. 

Just some thoughts from an Old Fud.