Final answer:
Timbre is the unique sound quality that distinguishes different musical instruments playing the same note and can be subjectively described with various adjectives. A lush sounding instrumental accompaniment with soft timbres and sustained chords suggests a full, gentle, and continuous quality of sound.
Step-by-step explanation:
The concept of timbre refers to the unique quality of sound that differentiates one musical instrument from another when they play the same note. This inimitable sound quality, often described with adjectives like warm, rich, and pure, results from the combination of frequencies, intensities, and the instrument's resonance that shape the sound's character. When an instrumental accompaniment is described as having lush sounding with soft timbres and sustained chords, it suggests a rich, full texture with gentle and continuous tones, which could be considered true based on the subjective nature of how timbre is perceived and the typical qualities associated with a 'lush' sound.