Loud thud heard through speakers


Noticed a weird sound while listening to music today. A loud thud through the speakers during loud vocal passages. I'm not sure what's causing it but happened twice and on different records. One was Muddy Waters Folk Singer and the other Dire straits Brother in arms. 

Amplifier: Graaf GM50BSpeakers: Wilson Benesch ACTSubwoofer: Sumiko S9
At this time I'm not sure of it's the Sub or the Speakers. Did anyone experience anything like this before?


livin_262002

Showing 5 responses by livin_262002

@cal3713 Thank you for the suggestion. I'll try playing same tracks from a digital source today and see if I can induce the pop. If there's no pop then as you said it could be a problem in my analog chain.
Update. It was bad buffer tube in the phono stage. Replaced the tube and all is well now.
@yeti42  thank you for sharing your experience. How loud was the thud you heard? I was listening to music at moderate level, listening to Muddy Waters Folk Singer. When his vocals got loud is when I heard the thud and both times the noise coincided with Muddy's vocals getting loud.

My stereo is about 18ft from any kitchen appliance. The amplifier is currently plugged into a power conditioner too.
Ok, narrowed it down to the Sub. The noise is not coming from the speakers but from the Sub. Not sure why the Sub is popping so loud during loud musical passages even though there's hardly any low frequency information at that moment.