Zephyr,
From what I have seen the S5 appears to have severe compression issues above 2KHz. So I am not surprised that the TAD (a reference speaker design) would make ones ears bleed if one was used to all that compression (congested laid back treble lacking the ability to convey true dynamics and harshness of horn instruments and percussion). In essence, a reference style loudspeaker is always more likely to sound harsh compared to more popular audiophile style speakers that can be kinder to the sound.
From what I have seen the S5 appears to have severe compression issues above 2KHz. So I am not surprised that the TAD (a reference speaker design) would make ones ears bleed if one was used to all that compression (congested laid back treble lacking the ability to convey true dynamics and harshness of horn instruments and percussion). In essence, a reference style loudspeaker is always more likely to sound harsh compared to more popular audiophile style speakers that can be kinder to the sound.