woofer pumping


Today I tried to play some vinyl through my new setup (Dynaudio C1 speakers and VTL MB-450 amps/VTL 5.5 pre) and I noticed a large amount of woofer pumping (Whenever I listen through the CD player or Squeezebox the woofers barely move at decent listening volumes).

My turntable is a Technics SL1200, cartridge is AudioTechnica 440 MLa and the phono pre is a Cambridge Audio 640P. Nothing fancy but the woofer pumping is worrying me and I'd like to reduce it. It's currently sitting on an Ikea Expedit so it's not the best for isolating vibration since just tapping it immediately makes the woofer travel more.

I was thinking of getting a 4" maple platform from Mapleshade with the Isoblock footers. Any other suggestions?
jibbonacci

Showing 2 responses by steveaustin

I second (third?) the KAB Rumble filter suggestion. Really no sonic compromise I'm able to discern when using it -- no more woofer-pumping, and the 'table is also actually now less vulnerable to footfalls (no more tiptoeing around when listening to vinyl).

Another benefit besides the obvious reduction/elimination of woofer pumping is that your amp (and sub(s) if applicable) will no longer waste a lot of energy and effort trying to reproduce those inaudible low frequencies that cause those woofers to frantically pump away. No point in having your amp struggle to reproduce something you can't hear (and can only 'see').

Got mine here on Audiogon used for around $150 - turned out to be a great investment for me. Any concern I had about adding something into the chain and possibly degrading the delicate phono signal has been far outweighed by the more effortless overall presentation I'm getting when listening to records.
Good points, Newbee. I hadn't considered that the arm on Jibbonacci's Technics may present a mis-match with the Audio Technica cartridge he's using.