Obviously every single instrument whether amplified or not, even synths have an inherent timbre. I'd posit the timbre inaccuracies we hear in playback as compared to the original timbre as captured in the studio or live concert are relatively minor for causing stress vs other aspects of sound. I suspect tonal anomalies or imbalances are a much greater cause of listener stress, tonality is a gross measure, more easily heard than the relatively small timbre anomalies we are likely to encounter. On the other hand, I can think of at least one pretty persistent irritant for what I believe to be timbre issue, and that is massed violins, I've yet to experience a fully natural presentation/timbre via digital, vinyl reproduction sounds more like the real thing although digital has continually evolved here.
@mahgister I've long known of your intense experiments with room treatments, interesting diy projects, no doubt you've visualized sound waves. I too have experimented with multiples of off the shelf devices and/or just plain furnishings in listening room. In my experience virtually everything has some effect, 1st reflection points while the most obvious are not close to the end of it. With experimentation I've learned to be far less invasive with 1st reflection points and treat many other reflection points throughout room. Since I don't really have wall behind listening position around 15' into 30'L room opening into a kitchen I got far more immersion into sound field using 6 Synergistic HRT on side walls behind listening position. Having a wall close behind listening position changes the whole equation. I also used multiple Schumann resonators in the past, can also be very effective if used correctly. To reiterate, maximizing sound staging, imaging is extremely important for my ability to easily enter higher levels of ASC, immersion into the sound field meaning stimuli emanating from behind listening position is key.
