Calibration Ruins Impedance Measurements

[bangiel]

No filtering looks better to me:

 

[bangiel]

And here's 4M, High Filtering:

 

[bangiel]

Ok, the grand finale. I ran 4M, High Filtering during the calibration and measurement steps:

Mesa Traditional 4x12 (Celestion V30s) - no port (afaik)

Mojotone Grand Canyon 4x12 (Celestion V30, Mojotone BV30H) - rectangular port at bottom of front baffle

Mojotone Twin Canyon 2x12 (Celestion V30 and G12H75) - rectangular port at bottom of front baffle
(this one stands out to me because of how many peaks I measured)

Mesa Widebody 1x12 (Celestion C90) - triangular port on the right side of the front baffle (relative to looking at enclosure)

Mesa Widebody 1x12 (Celestion V30) - triangular port on the right side of the front baffle (relative to looking at enclosure)

 

[John Mulcahy]

The multiple peaks in your initial measurements may be due to the different resonances of the 4 drivers in the enclosure, the single driver measurements are more typical of what one would expect as folk are mostly measuring single drivers.