AFMG Network Forum

intercessor · Member

Hi,
I have two questions regarding Ray Tracing w/ Impacts. I looked over the manual but was unable to come up with a understandable definition.

1: What is the difference between "Impact Control" time and "Trace Control" time.

2. Why does the "Impact Chance" go down when "Time" in Trace Control is increased? If the time is lengthened would not that allow the trace to be in existents longer, and therfore increase the chance that it will impact the particular seat?

Thank you for allowing me to bug you...
intercessor

Emad El-Saghir · Member

Hi,
1. The difference between the two control times is the arrival time of the direct sound at the listener's seat.
2. For your second question, I will try to explain the issue as far as I understand it. If you consdider one source and one receiver in a given room, then the ray paths, which connect the two points and fulfill a preset reflection order and Snell's law of specular reflection, are deterministic and can be added by the program to the reflectogram if you allow for that through the cutoff criteria. Now, this time setting describes one of these criteria, namely the total travelling time of the ray path, and the impact chance is attributed to the total number of such deterministic ray paths. For a given number of rays per loudspeaker, if you choose a shorter time, then the ray paths that meet the reflection law and arrive at the receiver within that short time are less and shall represent mainly the first few orders of reflection, and that is why, it is more probable that they will be caught be the counting balloon. On the other hand, if you increase that time setting , you are now considering a larger number of ray paths with higher orders of reflection and the probability that the program will catch them for the same given number of rays per loudspeaker is less.
I hope this could be of any help to you.
Regards,