HELP-woofer moves alot when playing lps

A search on "woofer pumping" shows 22 threads.

Tbromgard

I recommended spending some time isolating your TT, Gear and speakers better so they are not affected by structure feedback. The speakers can in fact be aimed at your TT - sound pressure (acoustic feedback) itself is not the problem. When the acoustic feedback is absorbed by the rack, shelves, floor and walls around your TT, gear and speakers and changes to structure feedback - this then becomes the problem - if your TT, Speakers, gear are not isolated properly. See also the last 30 or so posts on Copernican.

IMO - Any filter not recommended by the speaker manufacturer themselves should be considered a 2nd option only after isolation attempts fail. Its a band aid, another layer.

Good luck.

Thanks for the responses. I purchased the KAB filter. I dont believe isolation is an issue-the TT is well isolated. Also, the tonearm manufacture believes cart/arm mismatch is not the issue. The arm and cart are both medium mass/compliance and should work fine togther-so I dont think that is an issue either. I really dont want to add another circuit path for the signal to run, but it seems inserting the KAB filter is my best choice. I will report the results once I rec'v the unit. Thanks all.

Tbromgard, despite claims to the contrary woofer pumping is not something that ported speakers are prone to.

My speakers are ported and go to 20 Hz. They don't pump particularly more on LP than they do on CD.

This is a common problem with arm/cartridge mismatches. Daned's comments above lead me to suspect that he has a problem with this too. If you have a heavy arm and a high compliance cartridge, you are going to get pumping. The 'effective mass' and 'mechanical resonance' of the arm/cartridge combination are the issues you want to study.

The KAB filter is one of the best out there but if you have a transparent system with bandwidth you may not like what it inevitably does. IMO/IME you are better off curing the cause rather than the symptom. Good Luck!

Oh, Ralph. Are you saying my Triplanar isn't up to handling an xv-1s?

Transaudio, let me explain. IME, when you put any filter in the stream you can hear the effects. Well, at least I can in my system. Woofer pumping, which we cannot hear, does cause issues in higher ranges that we can hear as distortion and or nulls. I guess the easiest way to say is that we don't hear the direct effects around 20Hz but we can hear the side effects. Stop that woofer from flapping in the breeze and the bass tightens, etc. Add some filters and you also crush dynamics. Get the right filter and you get the best of both but you still give up something. Pick the compromise that works best in the system.

In my case I use a Marchand crossover and the natural roll off of my bass horns. The Marchand keeps everything below 100Hz confined to the bass horn which rolls off very quickly below 25Hz. Kind of a built-in filter.