Can you tell how accurate the app is on your phone? If it is repeatable and linear, you can use it for relative measurements rather than absolute ones. Relative measurements should be fairly accurate. I'd be real suspect of absolute measurements such as you are taking.
I believe it was Linn, many years ago, who did some research on how much woofers move a cabinet. They found that the cabinet moves a hundred times more than the tweeter. This research brought about satellite speakers with the woofers in separate cabinets, if I remember the history correctly.
I believe it was Linn, many years ago, who did some research on how much woofers move a cabinet. They found that the cabinet moves a hundred times more than the tweeter. This research brought about satellite speakers with the woofers in separate cabinets, if I remember the history correctly.