How do you know when a stereo sounds good?

To me it's more of a question of "what am I missing?"  To some a single Bluetooth speaker is all that's required to be pleasing, to others every piece of the system must be analyzed tweaked, treated, compared and modified and it still may never be pleasing enough.  If being an audiophile is your hobby it requires a lot of exposure to a lot of different systems components and experimenting until you are satisfied that the choices you made are providing you with the "experience" you require. It might may be pleasing but still lacking or it may never be pleasing as you continue to obsess for that final 10%.

To be "pleasing" the system is just a vehicle that provides the recorded music you find pleasing.  Your priorities determine if sounds good or not.

Again to me Measurements Smeasurments.  Good sound can't be measured on an enjoyment scale as it's way to personal.  YMMV

@danager what you call an adult conversation is laughable. This entire thread is a joke. The premise was to evoke a conversation leading to testimonials and shilling Teds over priced gear.

There has been no conversation here and it is the same old boring BS.

I will make a contribution for you, buy some decent  cables, some magic elixir for your connectors and you will be in audio heaven.

Yawn…."

Did you stamp your foot when you wrote that?  

Three pages of posts would probably disagree with there is no conversation here and your childish disregard for everyone who did participate with your one word condescending smirk is probably wondering like I am "Who the heck cares whether your bored or not and why if that's how you feel would you think its at all beneficial to the post to add it?"

I don't see a product mentioned in the OPs post.  If I was in a business of providing products to a specialized demographic I'd also want to better understand my clientele.

If cables and elixirs bring you pleasure and that's how gauge your enjoyment great.  That at least moves the conversation instead of detracting from it.

If your system costs less than $100,000 you have a ways to go. I'm not joking.

Does labor count?  Newbies time doesn't count as much but after a couple of decades every hour spent listening, evaluating and studying should easily add up to 100K pretty quickly.  Or you could work at your real job and just purchase expensive stuff.  

Both methods are valid but one does not guarantee a better sounding system over the other and neither have anything to do with whether you are pleased with the result.

So you're the one.  Move to the right.  The left lane is for passing not camping lost in the music. 

Some measurements are critical. How wide is it? How tall and how deep is it? Will it fit on my shelf? How loud will it play?

All the rest of the measurements are just marketing. I can’t hear numbers or even verify what the heck they’re actually measuring it certainly isn't sound quality.

If numbers are really that important you should be buying a calculator instead of a stereo. When I rent a moving van do I really care what its 0 to 60 time is. I’m sure it’s measured somewhere but would you rent one because of that or how many boxes it holds?

After you determine where you’re going to put it the only thing that matters is HOW DOES IT SOUND TO ME?

If you can’t answer that question without relying on someone else's numbers, maybe you’re in the wrong hobby.