Bass and treble levels

Many of you have seen this, but here is a great write-up of how recordings changed over time.

https://www.shockwave-sound.com/blog/the-loudness-wars-over-compression-and-its-impact-on-music-qual...

I think it's important to note what we are sensitive to as well. 

I like tone controls, but my current pre's tone controls definitely dull the sound, even when set to neutral. 

Sadly, the design and parts quality of tone controls has really diminished. 

So this is gear dependent. I'm sure others may totally not hear this issue at all. 

So, I don't think there's one answer, except to please yourself, and pay attention to your perception in long term listening sessions. You'll eventually become your own mastering engineer and decide what's best. 

It is a personal preference. The speakers and room affect this as does the recording a great deal.

Also, listening levels. If you listen at low / background levels tuning up the bass and treble a little can help you pick up the missing details.

The thing I like to remind people is that mastering engineers may have been listening to and intending their music to be played back on very different equipment. Early U2 and Talking Heads was for cars and boom boxes. Mastering engineers were subject to trends and fads just as much as anyone else. They were involved in a subjective guessing game about how their product would be used and appreciated. 

Sure, it’s historically interesting how it was recorded, but damn if that makes it fun listening.

Movies are a whole other story thanks to THX. :) There ARE objective standards for sound reproduction, and room acoustics.  In music we are not so lucky, but the point of all music is enjoyment, not rigid adherence to some perceived standard.