Measuring a crossed over speaker, near-field distance

For a speaker with multiple drive units you would typically measure at 1m distance to see the overall response, at a height that corresponds to the typical listening height. If you measure very close to a drive unit, such as the 6" from the tweeter you mentioned, the contributions of the other drivers will be from very strongly off-axis and not be representative. Close measurements are fine if you want to look at the individual contribution of a single driver through its operating range, but otherwise you need more distance. Room effects can be reduced by gating the measurement to exclude much of the reflections, understanding the limitation that places on the LF limit of the measurement.

Thanks for the advice John, would that also be true for 'coaxial' speakers?

I would imagine coaxial speakers wouldn't be any different than an individual driver when measuring near field (i.e. <12" ideal). You have no other drivers offering their off axis contribution, so I would go with the under 12" and use a gate that takes the low frequency limitation into consideration.

Also remember to keep the mic boom out of the way as much as possible to remove reflections.

brucek

Matt, if you need them, brucek already offered more detailed instructions on setting IR gate times to avoid reflections here in another thread.

Thanks for the added responses I just wanted to be sure all of the measurements I did for the in ceiling speakers I did were good, I used a 6" distance for those.