Subsonic Rumble Solutions

Koegz said, "let's see, subsonic filter, rumble filter how about an air filter? to bright ad a tweeter filter. mids not right add a mid booster filter. how about, system sounds bad, get a better system."

Hey koegz, no need to worry about a subsonic filter when your speakers (B&W 800D) are allready down -3db at 35hz and are -6db at 25 hz!! You allready have a built in subsonic filter.And rumble, just think how much less rumble (and music) you are missing when your speaker is incapable of much below 50hz.

Ponder that for a moment and when you get full range capable speakers let us know.

Bob

Hello Srwooten,
Just curious, what cartridge did you upgrade to?

hey acoustat6, i knowlonger own the 800d's. i have had duel subs before. no longer, not part of the REAL sound of music. ponder this bob, when you get a real two channel system, you can let us know!

Markpao-
A Zyx Airy 3.

I too have contemplated this problem. I get pumping woofers although I cannot hear any of the sound being produced, I figure it's too low to hear.

I haven't checked since I got a new phono stage but I am personally of the view that this is a problem with the records and maybe the resonant frequency.

The reason I think this is record and pressing related is that it varies greatly between records. I get it worst on an original pressing of The Joshua Tree. I'd be interested to hear what records others see this effect on.

Another aspect is the cart/arm combination. Using the cartridge database I work out that the resonant frequency of my combo would be 9Hz. Now my speakers are meant to have usable bass down to 8Hz - maybe it's just the resonant frequency being reproduced?

I have done extensive tests with isolating my TT. My TT sits close to the right hand speaker and there is nowhere else to put it. I have done extensive isolation and this helped the problem but did not remove the problem. I have done 2 experiments to try and determine if the woofer pumping is caused by insufficient isolation of the TT:
1) I bought a cheap 5 metre interconnect cable, put the TT in another room and still got the woofer pumping.
2) I have also done another experiment where you connect one channel of your CD player to the inputs you normally use for the TT, leave the other channel connected to the TT - then you place the needle in the groove of a record with the platter stationary and put on a CD. The idea is that the sound of the CD should not come through the speaker still sourced from the needle in a stationary groove of a record. I haven't tried this for a long time but the amount of sound which did come through was not even close to enough to pump woofers.

As a result of these experiments I did improve isolation with a sand box but I still live with some woofer pumping. I'll have to check out how much I get with the current set up. I'm not crazy about the woofer pumping but I am reticent to add a filter in the signal path. I would try one of the Elliot Sound products filters but have absolutely no ability in soldering, maybe one day I'll ask someone at work to show me or do the soldering for me.

DS