Ye, I started to hear some new things but it is really awful and just very flat for me
A DAC (or any electronics) shouldn't have a particular "sound" unless you are using EQ/tone controls or unless you overdrive an amplifier (or something) into clipping (distortion).
Generally, DACs are better than human hearing.
I've only heard a difference or defect from a "DAC" once and it was a soundcard that made noise when the hard drive was accessed. I never heard anything wrong with the DAC built-into my 1st CD player 40 years ago!
With electronics there are ONLY 3 characteristics of sound quality - Noise (hum, hiss, or whine in the background),
frequency response (bass, treble, etc.) and
distortion (like when you turn up the volume and try to get 100 Watts out of a 50W amplifier). Frequency response and distortion are almost always better than human hearing unless you push an amplifier into distortion. Sometimes there is audible noise. Noise is an easily identifiable defect... Either you hear it or you don't and if you can hear it, it's not too hard to tell if one device is better than another.
With speakers, room acoustics, and headphones, it gets more complicated but it's mostly frequency response and in this case it's almost NEVER as good as human hearing. Speakers and headphones have the biggest effect on sound quality, by far. If you want better sound, get better speakers/headphones.
Audiophoolery describes the FEW REAL characteristics of sound quality. That should help you to ignore all of the flowery-poetic nonsense-language that you'll read in reviews and on most "audiophile" forums.
Ok,but how is it possible that sound is better without it when I use with very old dvd
It's POSSIBLE that there's something wrong with the old DVD player but you prefer that sound. Or, it could be the placebo effect (your brain fooling you). Or a volume difference can be perceived as something other than a volume difference. Louder usually sounds better, you can hear more details and louder is often described as "more dynamic", etc.
And there is a NORMAL perception based on the
Equal Loudness Curves that makes it sound like you've turned-down the bass when you've only turned-down the volume.
But the main reason for level-matching in a blind A/B or ABX test is that's it's a dead-giveaway to which one is A and which one is B, and the placebo effect can persist.
Even audio professionals and experts are often fooled (or fool themselves) in casual-uncontrolled listening tests!
What is a blind ABX test?
Controlled Audio Blind Listening Tests
