What Matters and What is Nonsense

I’ve been an audiophile for approximately 50 years. In my college days, I used to hang around the factory of a very well regarded speaker manufacturer where I learned a lot from the owners. When I started with audio it was a technical hobby. You were expected to know something about electronics and acoustics. Listening was important, but understanding why something sounded good or not so good was just as important. No one in 1968 would have known what you were talking about if you said you had tweaked your system and it sounded so much better. But if you talked about constant power output with frequency, or pleasing second-order harmonic distortion versus jarring odd-order harmonics in amplification, you were part of the tribe.

Starting in the 1980s, a lot of pseudo scientific nonsense started appearing. Power cords were important. One meter interconnects made a big difference. Using a green magic marker on the edge of a CD was amazing. Putting isolation dampers under a CD transport lifted the veil on the music. Ugh. This stuff still make my eyes roll, even after all these years.

So I have decided to impart years and years of hard won knowledge to today’s hobbists who might be interested in reality. This is my list of the steps in the audio reproduction chain, and the relative importance of each step. My ranking of relative importance includes a big dose of cost/benefit ratio. At this point in the evolution of audio, I am assuming digital recording and reproduction.

Item / Importance to the sound on a scale of 1-10 / Cost benefit ratio

  • The room the recording was made in / 8 / Nothing you can do about it
  • The microphones and setup used in the recording / 8 / nothing you can do about it.
  • The equalization and mixing of the recording / 10 / Nothing you can do about it
  • The technology used for the recording (analog, digital, sample rate, etc.) / 5 / nothing you can do about it.
  • The format of the consumer recording (vinyl, CD, DSD, etc.) 44.1 - 16 really is good enough / 3 / moderate CB ratio
  • The playback device i.e. cartridge or DAC / 5 / can be a horribe CB ratio - do this almost last
  • The electronics - preamp and amp / 4 / the amount of money wasted on $5,000 preamps and amps is amazing.
  • Low leve interconnects / 2 / save your money, folks
  • Speaker cables / 3 / another place to save your money
  • Speakers / 10 / very very high cost to benefit ratio. Spend your money here.
  • Listening room / 9 / an excellent place to put your money. DSPs have revolutionized audio reproduction
In summary, buy the best speakers you can afford, and invest in something like Dirac Live or learn how to use REW and buy a MiniDSP HD to implement the filters. Almost everything else is a gross waste of money.
@markalarsen :  Amen to that. And a good Dac can sound very musical when matched with other electronics (okay ... and speakers) that have been selected for a particular sound.
And sorry, ! was away from posting for a while till support fixed a glitch in my account. It wouldn't let me post.

For tweaking validation, I do what geoffkait does, and have some fun engineering out my own solutions for: isolation, room acoustics, record/stylus cleaning etc. And i basically try all, or most of the going tweaks. But I don't spend ton of cash on it. I reserve the cash for components and music.
I'm trying to figure out, now, if a DS is imperative for streaming music. 96/192 streams sound terrible thru my MF Vink 192. No top end, no bottom end.

So I have to take exception with some of what you wrote. I have listened to a variety of systems as a stereo hobbiest, and the best sounding ones are the ones with the best front end. I’ve listened to modest speakers that sound far better than speaker costing 10 times more when the front end is better. 

Regarding the listening room, taming the bass and reflections has a major impact on the sound. I’ve build and hung panels through out my listening space with excellent results. 

As a vinyl guy a better cartridge has a major sonic impact to what you can hear.

Upgrading the electrical recepticals to hospital grade provide a very cost effective sonic improvement. 
@ronres & mdosmar: 100% agree. In my particular (or peculiar?) experiences and listening goals, I could basically invert the levels of importance that the OP has suggested, no ... decreed.

Cartridges, tonearm, phono stage, dac etc., provided most of the major changes in sound FOR MY system. 
There has been a recent wave of hospital burglaries where confessed audio geeks have been caught trying to steal the AC receptacles. Sad...