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Did Fleetwood Mac's "The Chain" blow up my woofer?

System: Ortofon 2M Red > Musical Surrounding Phonomena II > PS Audio Stellar preamp > M700 monoblocks > Buchardt S400 

Phonomena is set to 46db of gain, 200pF capacitive, 50k Ohms resistive

The other day I was playing "The Chain" off of Rumors, and one of the woofers stopped entirely during the bass guitar interlude. It just went completely silent, no pops, crackles or distortion. The tweeter is fine, and I reversed the L and R channels to confirm this problem is in the right woofer. The volume level was a "strong" listening level (30 out of 100 on the Stellar), but not loud. We were still able to converse just fine without raising our voices much at all. I have certainly listened to these speakers much louder with other sources.

I understand the power amps are overkill, but I figured my ears would bleed far before I was in danger of blowing anything up. Was this distortion? Subsonics? Woofer pumping due to poor TT isolation? Or a simple defect in the driver?


jayy42

Showing 2 responses by mulveling

mulveling's avatar
mulveling
1,774 posts
 
This happened to one of my big Tannoys a year ago. Turns out a lead wire to the woofer became disconnected. Most likely the lead came from the factory with a marginal physical connection, and the large amounts of energy thrown around the cabinet during loud listening  (96 dB/ Watt efficient and 15" woofer) eventually shook it loose. Simple to resolve; my tech fixed it easily, and it's worked perfectly since then. No permanent damage to the woofer.

As noted by others, you'll want to make sure you don't have a rumble issue (my current system has absolutely no rumble or woofer flapping). That's extra energy that can only have deleterious effect. 
mulveling's avatar
mulveling
1,774 posts
 
If you have woofer pumping it should be visible, because the woofers will be moving a great distance at sub-sonic frequencies. Sometimes lighting can highlight the issue. When I upgraded my rack & turntable to the current ones, absolutely all traces of woofer pumping completely vanished - not that it was too bad before. It can be either your turntable, or lack of isolation, setup, or any combination. If everything is right, a rumble filter will not be necessary.

And my tech also checks the woofer's freedom of motion - if that's all good your woofer's mechanics are usually OK. 
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