woofer pumping

Newbee got it. The first place to start is the arm/cartridge compatibility. Not only will you reduce woofer pumping, but you get better sound if the cartridge and arm are working together.

Well that's a lot of replies with a few different possible solutions. I'll look at each one and see what I can do, but I really appreciate everybody's help.

If you still have the problem after all tips you have followed, try to distance your turntable as much from the speaker and see if it helps.

04-26-10: Newbee
No one has mentioned that the probable cause of the woofer pumping is a mis-match between the cartridge and the arm. This will do it every time. It is a arm mass/cartridge compliance issue you should investigate.

BINGO! I have an SL1210 M5G, so I have some experience with this issue. Fortunately, since the Technics arm takes interchangeable headshells, you can change the tonearm's effective mass to match the cartridge compliance by changing to a lighter or heavier headshell. The stock Technics headshell is 7.5g--very light--which works well with high compliance cartridges. I've found that changing to a 12g Sumiko or LP Gear Zupreme headshell raises the effective mass to match well with medium compliance cartridges such as the ones coming from Audio Technica and Denon. I have an AT150MLX and a Denon DL-160 mounted on these heavier shells, and they are both good matches.

According to the charts at the cartridge database, my arm/cartridge resonance comes in at an ideal 10 Hz with this setup on a Technics arm.

Furthermore, proper damping can reduce the amplitude of whatever resonant frequency you wind up with. The KAB fluid damper won't change the resonant frequency, but it will reduce its amplitude, which should make the woofers pump less without rolling off audible bass.

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.

No one has mentioned that the probable cause of the woofer pumping is a mis-match between the cartridge and the arm. This will do it every time. It is a arm mass/cartridge compliance issue you should investigate.

There is nothing wrong with using a subsonic filter but it better to fix the underlying problem than to add a band aid, I think. The problem still exists, you are just masking it. Additive is usually subtractive in audio.

FWIW, just a thought.

Thanks for the suggestions everyone... I think I may try the KAB rumble filter since it would be a fairly cheap fix if it actually works for me.

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.

IT SHOULD HELP BUT REALLY IT SOUNDS LIKE THE ROOM AND SETUP MAY BE ON THE SMALL SIDE. THE TT IS MOST LIKELY PICKING UP SOUND WAVES IN THE ROOM.

I CANT COMMENT ON THE BENEFITS OF A 2" VS 4" PLATFORM FOR YOUR TT. IT COULD BE SITTING ON A SLAB OF CONCRETE AND THE TT WILL STILL PICK UP SOUND WAVES IN YOUR ROOM.

START WITH THE 2" AND HOPEFULLY IT WILL TAME IT DOWN ENOUGH FOR YOU TO LISTEN TO YOUR VINYL UNTIL YOU MOVE INTO THE NEW SPACE

DIRECT DRIVE TT ARE NICE AND EAST TO USE BUT YOU DO END UP WITH SOME SOUND QUALITY ISSUES FOR THE ADDED CONVENIENCES

i use the cambridge 640p with a vpi scoutmaster and have no issues with rumble. i would think you should look into purchasing some manner of rumble filter first and then concentrate on better isolation after that.

There's a subsonic filter on the 640p but it doesn't do all that much... there's a bit of a difference, but slight.

Listening room is about 12x16 with the speakers setup on the shorter side (turntable is about 4ft to the side of one on the speakers). I'm moving from my current place soon which is why I haven't invested into a serious audio rack yet, but that's something that I'm looking into getting in the future.

In the meantime, would the maple platform and isoblock footers help the situation? (also not sure if the 4" would provide any advantage over a 2" in this case).

A KAB rumble filter will solve the problem.I use one and very happy with the results.

I would invest in a decent audio rack to start. Any subsonic filter switch on your phono pre? I'm gonna say you're getting feedback from the speakers being on the Ikea furniture. Being a direct drive TT will also add to the situation. Isolation is gonna be key.

How big is your listening room?