Grotrians most defining characteristic is it’s tone. A Grotrian treble is absolutely unmistakable, and there’s a very good reason for that: the octagonal strings gives it a highly specific overtone profile. According to the company, 8-sided string emphasises the fundamental and 4th partial, which happens to be very similar to silver church bells. As one plays a Grotrian, the choir comparison comes easily…the blending of the harmonics is hauntingly beautiful, and is arguably unique to Grotrian.
This feature is found on both their grands and uprights, but certainly the vertical models bring this characteristic out even more so, since the player is so much closer to the strings and the point of the hammers’ impact.