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Old 25th May 2012
Gear Guru
DanDan's Avatar

I am not predicting or making a qualified estimation. I am referring to events that occur daily in real life.
In two different tests in different rooms. Furthermore we see it every time we measure and move speakers or listener position.

Here we have a null which drops frequency with distance from the Front Wall.
One could suspect a link. Cause and effect.
A trap was placed between the boundary and speaker, blocking the suspected cause. The effect disappeared.
I would have difficulty not believing the obvious here.
Room Modes / Comb Filtering / Flutter Echoes-screen-shot-2012-05-25-16.25.36.jpg
I believe it was Hannes who suggested that FWBIR should, by level, have a strong effect on Frequency Response, while BWBIR should be more effective on modes. Logically, I went along with this.
Until I saw Ethan's test and repeated it myself.

In both tests, FWBIR and BWBIR were easily singled out by associating the nulls directly with distance. But BWBIR seems to have an unexpectedly very large influence.
I have yet to see a hypothesis as to why this is occurring.
I would welcome such, in the appropriate thread.