Measuring driver's acoustic centrer, voice coil distance

[wigginjs]

I'm trying to calculate values for an all-pass phase correcting filter, but I don't know how to measure the distance between each driver's "acoustic center" or voice coil. Information like the depth from the driver surface to the center of the voice coil is not given for the drivers I'm trying to integrate. How have people done this in the past?

Drivers:
Seas 27TDFC
Dayton RS150S-8
Dayton RS270S-8

[dlr]

Originally posted by m0tion
I'm trying to calculate values for an all-pass phase correcting filter, but I don't know how to measure the distance between each driver's "acoustic center" or voice coil. Information like the depth from the driver surface to the center of the voice coil is not given for the drivers I'm trying to integrate. How have people done this in the past?

Drivers:
Seas 27TDFC
Dayton RS150S-8
Dayton RS270S-8

If you can make measurements, try the link. If not, a good assumption is the former/diaphragm attachment point. Measure the depth for each driver relative to the front of the baffle.

Determining relative acoustic offset

Dave

[wigginjs]

I came up with this formula to covert degrees of phase shift into voice coil offset in mm. Could someone check this and tell me if it is right?

mm of offset = ((340.29 / crossover_frequency ) / (360 / degrees_of_shift ))*1000