For the guitar players
 

I've noticed something weird. Using bar chords only, play G then F, then D-sharp, then D. It's a progression of progressively lower sounds. Yet when you go from F to D-sharp, your finger that's creating the bar goes from the 1st fret to the 8th fret. Every string is pressed at a much higher fret, yet it sounds like a lower note. Instead of an optical illusion, it's an auditory allusion. How does this work?

I'm confused. Wouldn't a grand barre chord D flat be held at the fourth fret?
If you held it at 6th fret it would be a D sharp or E flat? Right?

Oops. I meant to say D-sharp. No wonder you're confused. I'm at work without a guitar. I fixed in it the OP.

Umm your not playing the D chords right

Been playing 33 years and I know I’m not confused.

Check your root notes

I guess the D-chord would be barred on the 7th fret. I just do it when I have my guitar with me. But yes, it would be the 7th fret, with the sharp on the 8th fret. I'll fix the OP again.

Just try playing G-F-Dsharp-D in bar chords. It seems odd to me that the tone keep going down even when you move up the fret board.

i'm glad i play bass

You’re doing it wrong. You need to play E flat instead of D sharp.

Maybe because by starting on G you have F as the 7 of G (leading tone) and D as the 5 of G (Dominant). So you're hearing 1(8) to 7 to 5 descending.

It's a common malady known as Pete Townsend Syndrome.

The D and D# chords sounds much higher than the F and G.
This is because they are. Something is wrong with your hearing.

My hearing is fine. I played just an F followed by a D# and my daughter in the next room said the D# sounded higher. It did to me too. But when I played G-F-D#-D, then the D# and D sound lower than the G and F.

I can't remember the last time I played a D#. Maybe it's just the music I play.