If it remains unchanged, the added sound and the surrounding sounds are roughly at the same pitch, which is relatively smooth. Strictly speaking, chords mainly depend on which notes there are and what the lowest note is. As for which octave each note is in, it is not that important.

For example, the C major triad C E G, as long as C is the lowest note, how many E's, how many G's, and how many different C notes are above it are all this chord. If the lowest note is E, it is the first inversion of the C chord. At this time, it is the same chord no matter how many C, G, or E are on it.