speaker driver makes a thud (right one) when amp power kicks in ???


New member
Aug 10, 2019
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hi , just started to notice a significant thud when my amp powers up ( mainly right speaker ) basically its the bass driver moving outwards !! . i have not noticed it before , the amp used to just click quietly when ready .

is this a sign of age , wear & tear etc ?? i have checked polarity & left right scenario all seems ok !! .

there does not seem to be any deteriation in sound quality when playing either .

i am currently using a nad cd (c521i ) & amp (c320bee) combo with acoustic energy speakers , silver anniversary single run speaker cable & qed one interconnects . (basically the five star budget setup from a few years ago )

if anyone has any ideas please let me know

best regards , rob .

Andrew Everard

New member
May 30, 2007
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Sounds like the amp might have had a muting relay to keep the speakers isolated until the amp powered up - that would have been the click when ready you heard before - but somehow the speakers are now connected when the amp is powering up.

It's not a big problem, and shouldn't cause any damage, but you could get round it by making sure the volume level is always right down before powering the amp up. I don't reckon it's anything worth getting the amp serviced for, and it's certainly not a problem with your speakers.


many thanks for your reply !! i am considering an upgrade in the near future anyway . but this system has given me a good few years of listening pleasure & does still now . i'm glad it does not seem like a major problem & will stick with it for the short term .

best regards , rob .

p.s i still get the quiet click as well as the thud of the bass driver moving if that makes any difference !! .