Woofers pumping


On two occasions I have noticed the woofers of one speaker moving 1/2 inch excursions. Both times the SPL was peaks of 93 dB.

System is CD player, preamp, amps.

This has happened with two different amplifiers.

I spoke with the tech at B&W and he didn't have an answer.

tomcarr

@atmasphere Good advice!

I am supposed to be getting a new CD player tomorrow that I ordered a month ago.

I will be going through all the suggestions.

Thank you.

Second the motion on switching speaker cables and seeing if the pumping motion moves over to the other speaker. If that happens, then the source is the problem. 

I have a few recordings that do have subsonics. One in particular is a CPE Bach recording in which the orchestra and audience were apparently on a wooden stage or platform along with the microphones and you can hear the subsonic rumble from people moving around. That's just one example. Another cause of this in the old days was from warped LP records, or turntables that were poorly isolated. The pumping motion of the woofers was very obvious. 

@erik_squires The woofer is just a slave...

Doh! I should have known that. Good point. Even more embarrassing, I've been involved with this hobby since 1975...🙄