What is this man doing?

[Guest]

On the Classic Speaker Pages under AR Miscellaneous Documents, in the "AR Speaker Specifications - February 1971" document, there's a photo of a man in a plaid shirt apparently listening with a stethescope. It appears that he's listening to the woofer frame-to-cabinet joint. What exactly is he doing?

It's my guess that the cabinet is somehow pressurized using an unseen compressed air source and he's listening for air leaks. Is that what he's doing?

The question arises then about the necessity of making the enclosure air-tight. Should care be given to seal speaker frames to the cabinet when reinstalling drivers after removal for service, ie. refoaming? Also, shouldn't some consideration be given to replacement crossover potentiometers that might leak more air than originals?

[Guest]

You hit the nail right on the head, this is sealed enclosure and requires a air tight enclosure.

If this is not achieved then air will audibly be passed in and out of the poor seal in the enclosure and the effective air spring will not be effective.

This is another reason to be extra careful when replacing the surround on the bass units to provide the correct seal.

Regards

Barry