And the biggest influence on sound quality is...

 the best enhancement to SQ is a bong hit

That has done some magic as far as my auditory perception goes!  

I really think it comes down to the quality of the bong.  Is it a natural bamboo bong, glass, or something makeshift?  The best SQ is always realized thru bamboo and good headphones 😂

Tom, Happy Friday! You don’t have enough room treatment.. ; ) Kidding aside, with that marvelous system I’m certain you are getting exceptional sound. Your experience with aweful recordings sounding awful, and great ones sound great, surely is a sign of a transparent system faithfully reproducing whatever recordings you play?

@troutstreamnm , I have often just threaded a couple of AN fittings together and made a  (to borrow from you) makeshift pipe with a small bowl, and nirvana always followed.

One thing that we cannot fix is the quality of a recording, and I would, perhaps, argue that a good system might make a bad recording sound worse than a system with certain limitations (e.g. a soft system top end taming a hard recording).  

Also, my ability to optimize my listening room is very limited as it is my Living Room, and has to function as such.  I think it is not too bad, it is a large room, about 20x36.  My speakers are 10 feet from the back wall, my listening couch 12 feet from the speakers. The usual living room furniture,with heavy curtains that can cover the windows.

Therefore, I'll offer up thoughts on relative importance of components in the goal of reproducing excellent recordings optimally.

The hardest things for a manufacturer to get right are probably the mechanical components: viz. the speakers and turntable/cartridge combination.

Then to my mind the DAC is critical.  If we compare digital ca. 1985 and 40 years on we are living in a different world.

Pre-amp and Power Amp obviously affect the sound, but, after a certain performance level, at a second order of sound quality differences - and often in subtle ways.

Cables do have different effects on the sound, but, after again, after a certain level of performance, the difference between well engineered cables is (to my elderly ears) very subtle. 

Without really thinking this through my own components reflect, perhaps unconsciously, my thoughts expressed above.  My pre ($3.5k LA4) and pa ($5k XA25) or my home brew 6SN7 300B balanced($5k) are dwarfed by the $55-60k on DAC and Speakers.

Replacing my pretty good Audio Physic Virgos with the outstanding Rockport Atrias was startling, then replacing the good Esoteric X-03SE with the K-01xs was another significant level of improvement.

I do admit I'm contemplating upgrading the DAC to the K-01XD.  I'm hoping I can find a dealer where I can take my existing unit and compare with the XD.

I was going to say your room.

1. Attitude. I've been moved to tears listening to music on a cheap transistor radio.

2. Speakers. Assuming you have a reasonable set up (whether inexpensive or otherwise), better speakers will make the most obvious improvements.

3. Room. I'll venture to say most people have little control here, and are unwilling to move their speakers or spend enormous sums on room corrections. For those who are willing, a good room can make a mediocre system sound good and a good system sound great.

Brain!  Can't say how many times I've just been driving down the road listening to the mediocre system in my pickup truck enjoying the heck out of music.  Ear/brain adjusts to quality. 

That's not to say audio quality isn't enjoyable.  But I would hope most folks wouldn't turn off a mediocre radio if the tunes were good! 

Disregarding the quality of the recording and considering some people have no choice on the room, strictly speaking equipment wise, I have to go with the amplifier.  I have found just playing around and substituting different components in a system that a very high quality amplifier will make even some of the worse speakers sound so much better at least to their dynamic and frequency limits.

Over the years and upgrades, I have found the preamp upgrades I have made to have the most significant effect on SQ.

Approximately 50% of the sound that reaches your ears in a residential sized room is from room reflections. I've heard systems comprised of nothing but superb quality, well matched components sound horrible in bad rooms. And systems composed of mediocre components sound engagingly musical in good ones. All depending on the room and setup (positioning of speakers & listeners). Naturally some recordings are disasters that sound bad regardless of anything else, but in a good room can still deliver a taste of the artists.

If your goal is to hear performances where you get a real sense of the performers & instruments, deal with the room first. 

BTW, taming a bad room may not require expensive and non-homelike room treatments. In overly reflective rooms (more common than overly damped ones), there are many steps one can make to control those reflections. Rugs, shades & drapes, soft furnishings, textile art. David Wilson told me long ago that shelved books and records make some of the best acoustic treatments.

Bass response varies tremendously around a room due to the effects of standing waves. Sometimes simply moving one's listening position a couple of feet in one direction or another can turn anemic bass into rich tuneful bass (or go beyond into flatulance).

While electronic room correction systems like Dirac can make a big difference, one is almost always better off first minimizing the sonic elements that need correcting.

Being present for the music.

I find this most influence (for me) is to be able to chill out and not listen with the "looking for imperfection" mindset I cannot seem to escape at times, and instead just turn the lights low, lower the needle (or whatever I may be using), and exhale. It’s a big ask.

Like for me zeroing in awe on a Ron Carter bass line or Elvin Jones brush wondering right in that moment, hmmm, perhaps there is a way I should lift the needle and play my other copy, search another master to stream, swap a cable, turn off all appliances, move those home made bass traps, move my paintings to other places on the wall.

Just not then.

On a more practical front, the master bar none.

Your room. The least sexy part of the process unless you can afford to hire a pro to do the whole thing for you. Most tweaks make micro differences, room treatment  is a macro difference. Huge in most cases. 

A wife that thinks 50k is a reasonable amount to spend on stereo gear for the living room....

You have your system and your room...but a good recording in a big open,wood floors won't really help.

@hallock01 

Classic. 

There is a reason why many speaker designers test their products in anechoic chambers.  Doing so eliminates the effects of the vagaries encountered in rooms in which the speakers may be used.  On the other hand, some designers try to make speakers that are "room friendly," IMHO an impossible objective.  There are too many variables, with rooms of all shapes and sizes, containing reflective and absorbing surfaces, and furnishings of all kinds.

So what is an audiophile to do?  

First, have a room that your significant other allows you to take over. Then treat the crap out of it!  I have a 25X15x9.5’ room that I have treated with sound-absorbing panels, on walls, and ceiling.  I am able to do this on three walls and the ceiling.  The 4th wall is partially taken up by a brick fireplace, so no panels there.  However, there are panels on both sides of the bricks. The floor is tile, covered in substantial part by a rug with a layer of padding beneath it.

The panels went up a bit at a time. Each time I added more, I could hear performance changes, always for the better. 

Naturally, I kept adding more panels.

In my room, I can hear changes when about six of the 1-foot square panels I used are added.  Less than that, I can’t discern much difference. 

It makes perfect sense. The panels make the room less reflective and quieter.  The quiet is measurable with a good sound pressure meter. More quiet allows audibly greater detail and improved dynamics. 

For those with the funds, I recommend that you have your room treated professionally.  But it can also be a DIY project for those so inclined and capable.

My current setup includes Tekton Double Impact speakers and a pair of their self-powered 4-10 woofers, a Muzishare R100 805 integrated Single-ended amp (into which I’ve poured a lot of $$$ for tube upgrades and performed an internal output capacitor bypass - a potential subject for another discussion), the Audiolab 9000 CD transport, and the Gustard R26 (ladder) DAC. The transport and DAC are powered by a battery power supply (a nice improvement that can be had for far less than expensive power cables and filters). The speaker cables are the extraordinary Wireworld Eclipse 10. I use two pair since my speakers are bi-ampable. (As a major speaker cable skeptic, I have been amazed by the changes wrought by these cables.  I run 20-foot lengths.)  Sitting idle are my upgraded Parasound JC2 preamp and A21 amp, and a speaker system comprised of rare, classic Altec drivers in expensive Japanese-built cabinets, with German-built horns atop for frequencies above 400 HZ.  (All else being equal, I am spoiled by sensitive speakers).

And the biggest influence on sound quality is...

Stepping on the cat’s tail.

No matter how great the system, the room, or whatever, musical engagement goes out the window when self preservation from scratches and sharp teeth kick into high gear.    🐈‍⬛  Meooooooooooooow….

Linn's philosophy has always been source first.  And I agree. If the source is bad all the equipment in the world can't fix it. It will only be lipstick on a pig.

Your mental state of mind.

With my near SOTA set up in a custom built listening room, with 61,100 CDs/LPs/78s/R2R recordings, the quality of the sonics vary but have improved to such an extent that fewer than 10% of my recordings sound less than good and enjoyable.  Even among those drenched in reverb or poorly miked/mixed or dating back to 1900, there is musical enjoyment to be found.  I've disposed of 18,000 records and still have to cull another 10,000 (for performance reasons). It is shocking how much fun and enjoyment there is throughout my collection.  For over 60 years I also determined based on lesser equipment what was great, not so great, okay and truly awful to listen to.  Now, it is rare to find an awful sounding recording in my collection.  A great audio system in a decent room will provide  an endless abundance of musical and sonic pleasure (I don't stream much as 85% of streaming quality is inferior to my recordings and maybe 50% unavailable to stream).