Understood, I just want to cover all the bases. There are a variety of factors that would prohibit this from registering.A quarter-wave dip, if it's there, would be measured back at the driver, however the energy reflecting off the far wall should still register as a slight rise in SPL for that frequency. This is not seen in the results.
When you do this could you also meausre 1" from the driver? This would satisfy the conditions I previously outlined.I'm going to do another set of measurements to look at how the intensity of these peaks is reduced outside the box. This involves taking a measurement as before (just at one spacing, probably 500mm), and then removing the meter without moving the wall. A second sweep will then be done and the SPL measured outside the box at 1m from the driver.
The audibility of these peaks and dips will be related to Q, source material and frequency (there has been large amounts of research on the audibility of such issues). In the end it doesn't really matter since simple steps can be taken to fully remove these anomalies via proper damping . Then again, my goal is always perfection...This will show just how much importance should be attributed to these resonances. As an adjunct, any quarter wave dip should be visible in the second measurement. How does that sound..?