1. Try turning Diffusion OFF (using the power button). The diffusion algorithm adds a bit of delay before both the Early Reflections and the Tails. This delay is especially noticeable when Size is large.
2. If you have Early Reflections at a low level, then the Tails will appear to have substantial predelay. This is because Tails are meant to occur after the early reflections.
Consider turning Early Reflections all the way up, or else turning them OFF (using the power button). When Early Reflections are off, the Tails become instantaneous.
I hope this helps.