Do you sometimes hear a bass note as two notes or a chord?

[bbh]

Ok. Strange questions maybe, but here it is: I always had a very good musical ear, since I was a child, with bass everything is different... first of all, I sometimes hear a note and I cant tell between 2 or 3 notes that are a part of a cord... its like my head is automaticly making a chord, its only with bass, not other instruments, also, sometimes the note is "changing in front of my ear" it starts as a certain note (attack?) Then goes up or down, sometimes its so bad, I feel everything is out of tune, but when I check, its ok. With the vox amplug and earphones it happens less. Sometimes I feel Im losing my hearing (and my mind) the changing pitch thing of the notes, I remember it happening to me as a teen. (When listen to reggae, for example, when the notes are slower and longer ...
Is it normal? (My father says the same thing happens to him )

I’d like to suggest custom molded earplugs. It really cleaned everything up for me. My ears go mushy after a few songs in louder situations.

 

[Bubble]

I need to wear ear plugs because my ears distort long before my Ampeg BA210-v2 pumping only the native 210 cab and the 115 unplugged. MUCH louder with the 115 plugged in.
It's also possible to hear harmonics (multiple notes) on the lower 1/3 or a bit farther up on the neck. I scoped the waveforms, they begin at open string with a good bit of harmonics but at the 12t frets and up I was seeing very close to sine waves.

 

[vancamp]

Also, if you're perceiving the intonation shifting, it's possible... as a note rings, the relative amplitude (loudness) of the different harmonics will change. The actual harmonics that a string with mass and stiffness under tension generate aren't pure... look up the term "inharmonicity" to get more info. It's something that piano tuners have to deal with all the time. So some of the harmonics may not be quite in the same tune as the fundamental (which you presumably tuned the string with). You may be "hearing" the intonation from one of the upper harmonics.

 

[Bubble]

I have noticed that effect, I call those "wrong" harmonics zingers. They sound a bit like an old spring reverb for a guitar amp but very subtle.