HELP-woofer moves alot when playing lps

When I play a record on my TT, I get an excessive amount of woofer movement, even when no music is playing. When I lift the arm off the record with the finger lever, the movement stops, and the phono stage is dead quiet. Its only when I drop the needle and turn it up a bit, the woofer starts to move in and out. I dont get this when playing cds, only lps. I have my system on a shelves, with the table onto and my integrated amp directly under my TT. Might this be an isolation issue? Thanks in advance.
Might this be an isolation issue?
Mightl also be rumble from the TT motor or possible arm/cart resonance in the subsonic/low bass range. If it ONLY happens w the needle in the groove and the volume turned up, I'd have to think that acoustic feedback is the issue, whether air-borne or structure-borne.
Switch on your low pass filter.... that will solve the problem..
Thanks Swampwalker-
Yes, it happens only w/ the needle in the groove and the volume turned up.
Try engaging the subsonic filter if you have one-sometimes lps can have a slight warp or off center spindle hole that cause spurious low frequency excursions.
I have a Musical Fidelity integrated amp-there is no subsonic about a inline filter to remove rumble...does anyone have experience with such a filter?
I have experience with the KAB rumble filter. I had the same problem in my system with my VPI turntable. The filter attaches through the tape loop and I can hear no difference in the sound quality with or without the filter engaged. It totally stops the woofer pumping/oscillateing.

There was one for sale on here a while ago. I bought mine new from KAB. The insides are stuffed with audiophile parts, so it isn't a cheap piece of junk.

Are your speakers sealed or ported.

This is a very common problem.

Search the net as this subject has been covered in depth countless times.
Cartridge arm mismatched. Not much you can do.
It is NOT cartridge/arm mismatch. Ported speakers are a bit more susceptible to this. My old Aerial 10ts would do the woofer dance very well. Make sure your amp has enough headroom so you don't get clipping, put the covers back on the woofers. Stop watching them. The suggestions for a subsonic filter are good, but I have not heard one that didn't seem to damp things too much. It could work for you. You might have some success experimenting where the speakers are placed, but you probably can't eliminate it completely.

I have two, 18" drivers handling the duties down low. On a lead-in of a slightly warped record I can feel them pressurizing the room from side to side. :-)

I suspect you are correct that it is NOT cart/arm mismatch (its rega and clearaudio). If I ignor the issue, wont the woofers be damaged by too much pumping?
no, just play your music and ignore the woofer movement
It is a problem. Years ago I blew woofers twice on Vandersteens before addressing the arm cartridge mismatch. I use a test record (SHURE TTR115) that will let you know at what frequency the cartridge resonates at. It should be around 12 hz - well below and above the warp region. These are jus the facts my friend, just the facts!!
How do I address the mismatch? Should I get a different cartridge? Thanks.
Yes or a different arm.
I solved that issue in my ported speakers (and sub) with some "old stock" Nakamichi rumble filters (30hz) seemingly with no audible effect on the rest of the can still buy filters pretty cheap on Ebay...when I switched to a line stage preamp I bought a Cambridge 640P with its 20hz switchable filter that works really well, again with no audible issues.
Do a search in discussion forum under COMPLIANCE and it will explain tonearm cartridge matching.
I said in a previous answer I use the KAB rumble filter. I consulted the manufacturers of both my turntable and speakers, and after I told them everything I tried, other than changing the cartridge and or arm, I was advised that the rumble filter was the best option without degrading the audible sound quality. The speaker manufacturer told me you can severely damage the woofer if it oscillates so much that the woofer cones exceed their parameters.

Try out the KAB filter, you have nothing to lose. You can always return it within 7 days or sell it here.

Hi, **I suspect you are correct that it is NOT cart/arm mismatch (its rega and clearaudio). If I ignor the issue, wont the woofers be damaged by too much pumping?**

Right the first time. It's unlikely an arm/cart resonance problem and yes the woofers can be damaged eventually, especially if they bottom out. The major cause of woofer pumping is acoustic or mechanical feedback. If you get a wall shelf or suitable support and position where your speaker isn't playing directly on it, chances are you will cure the problem. If this isn't feasible maybe you should get a subsonic filter as suggested.
You can reduce the size of the ports with some cut foam strips (assuming your handy). This will increase the damping factor and reduce the pumping. A peripheral turntable platter clamp may also help. A subsonic filter did not have any affect in my st-up. FYI, I use a pair of ported full range floor standing tower speakers with the port diameter reduced. Note that is would be extremely rare for your woofers to be damaged. Don't let the handful of responders get you paranoid.
Agree with Stereo5 - the KAB filter is the best thing going to eliminate this issue. I love mine - zip zero nada downside to using it, absolutely no negative sonic impact and 100% solves the problem.

I have mine between my phono stage (PS Audio GCPH) and amp (Cayin A-70T).
We don't know what speakers we're talking about here. Whether or not the woofers could be damaged depends on the size of the woofer, it's excursion capabilities, and the extent of the pumping. MANY woofers will be damaged by repeated linear excursions in excess of their capabilities. If the pumping is severe, it's a recipe for disaster. At the very least, you're getting lots of distortion. If you get/make a more suitable mount for your TT, it will probably sound much better and eliminate the pumping. If the pumping is not severe and bottoming out, you can probably ignore it, and wallow in mediocrity.
From a speaker perspective, big movement like that is way wrong. You are seeing a speaker attempt to reproduce a subsonic wave, introduced into the system by the playback system (turntable). Count how many times a second it moves and you have the freq-5Hz-7Hz? Subsonics eat up all your amp power as your amp is attempting to reproduce what you cannot hear and the power curve is highest in the low end. Moving woofers in out to their extremes as pushes the drive unit coils out their gaps (there is a point inside the coil where it is centered n the magnet and outside that, distortion goes straight up). Loud enough, it will damage the woofers as they are not designed for subsonics. Now normal audio is now riding on top of that woofer moving in and out, so its "smearing" everything. A mess for sure. FIx it fast.

Get rid of the subsonic input -a filter is the your best initial choice. Some built in subsonic filters are not so good-they are too high or use to slow a slope-like 40Hz is too high and if its slope is only 6 dB per octave, 20Hz will only be 6dB less than 40. If you still see some woofer movement after your engage your filter, or can hear the filter dramatically change the low end, find a better filter. However, some low end change is better than the tremendous masking artifacts and distortion the subsonics are introducing elsewhere. Subsonic filters at 20Hz are ideal, and a steep rolloff, like 18dB per octave would be best (20Hz 18dB per octave would mean 10Hz is 18 dB down from 20Hz). I defy anyone to hear a 20Hz filter (if you can, turn yourself in to science).

Next, find where the subsonics are coming from: a bump in the turntable /motor/belt? Acoustic feedback (improper mechanical or acoustical turntable isolation from the speaker)? Warped discs? FInd it and fix it. The KAB company makes an argument that rumble can be introduced by the cutting lathe (built in to the master disc) and this is true, but far less common than turntable/disc related problems within a turntable/disc warp/isolation. Most companies tried to catch cutting lathe issues on QC.

A search on "woofer pumping" shows 22 threads.


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.
As it happens, the Clearaudio Concept MM I purchased-broke. The needle was slowly moving to one side of the cartridge, and now is totally limp. I am going to return it as it seems to have a manufacturing defect. I purchased the Orotfon 2M Blue, which will arrive soon. Hopefully once it is installed I will not experience woofer pumping.

Thanks again for the responses.
Hi Dan_ed, I have a Triplanar too :) -and no, I'm not saying that. If set up right it handles the widest range of cartridges of any arm I've seen.

For more on this, take a look here:
So when Atma-sphere amps show up not working one should assume they weren't built or serviced properly?
Dan_ed, At the very least, yes, though I don't understand what you are getting at at all. I feel like you are misunderstanding something though as there appears to be animosity on your part.

So maybe I have not been clear enough:

Woofer pumping is not a symptom of a speaker unless you are driving a small speaker well outside of it bandwidth limitations. IOW if the problem shows up on phono and not CD, its a problem with the phono and not the speaker.

Woofer pumping is a symptom of an incorrect cartridge setup, wherein the cartridge compliance combined with the effective mass of the arm causes the combination to have a mechanical resonance outside the range of about 7-12Hz.

Generally I would make it out to be too much effective mass coupled with too much compliance in the cartridge. IOW the cartridge's cantilever is moving a lot and the arm mass is not keeping up with it.

Fortunately with the Triplanar its easy to try the various and different weight setups until you find out what seems to work best with your cartridge.

So in this case to reduce the effective mass, you would put a heavier weight closer in towards the bearings of the arm and set it up for the same tracking weight. This will give the cantilever more leverage to move the counterbalance weight and so reduce deflection of the cantilever. This in turn reduces woofer pumping.

Does that make more sense??
Hi Atmasphere,
**Woofer pumping is a symptom of an incorrect cartridge setup, wherein the cartridge compliance combined with the effective mass of the arm causes the combination to have a mechanical resonance outside the range of about 7-12Hz.**

That's possible but often a compliant cartridge on a med/heavy arm won't cause pumping, even if it's resonating at 6Hz. Acoustic or mechanical feedback is a much more likely cause. Turntables on top of equipment racks, susceptible to mechanical shock, are more prone to have problems. They are likely to have problems even when there is no cu/arm mass mismatch.
Fleib, there is another thread on this subject that is current as of this writing, that does address this issue also:

Read the posts by Tonywinsc that occur on 09/13/11.
Real cart/arm mismatches are rare these days and hard to accomplish unless one is intentionally doing so. Am I one of the few guys who has the usual number of slightly warped LPs in his collection. That is THE #1 cause of woofer pumping, IME. Generally speaker, because of the way in which ported speakers gather extraneous energy to be released at that tuned frequency does allow ported speakers move more easily and to a greater degree when a warped LP is played. IMO, IME.
My cartridge/tonearm combo is perfect on paper and confirmed thorough a test record. Nevertheless, I would get woofer pumping on some records, but not others, which clearly indicates the problem lies with the record, not the system. This also confirms what KAB describes on its website about the subsonic/infrasonic frequencies being imparted on the recording by the disc cutting system. The KAB filter solved the problem and I never looked back. I think the argument about sound degradation is silly; you actually improve the sound by not wasting your amp power trying to amplify infrasonic frequencies and your speakers trying to reproduce them.
If by some miracle your system is free of rumble problems, God bless you, but for those with well matched carts and tonearms and no isolation problems still experiencing woofer pumping on some records, a good quality subsonic filter is the answer.
You people intrigued me. Now I want to experiment and create big bloody woofer pumping in my system. God bless me.
And what system would that be, Inna? If you call listening to records "experimenting," no wonder we intrigue you.
Isn't analog playback fun? The old adage, "Ignorance is bliss." holds true. Just like an onion, we peel back the layers just to find more layers. Cartridge alignment, cartridge tracking, VTF, VTA, suspended turntables, rigid turntables, high mass, low mass, wood floors, concrete floors, ported speakers, unported speakers, wiring, tubes, on and on. No wonder so many young people walk around with mp3 players plugged into their heads!
I love this hobby! I really do. As frustrating as it is when things go wrong, it is just as rewarding when finding a solution. It is like we each become an active participant in the music. So many good solutions to overcome the typical problems. And Audiogon provides us with a great support group when we hit a wall. There, I just wanted to say that.
I think everyone is right regarding what has been said on this page. All the different types of turntables, speakers, and electronics in-between lead to many different solutions. I experienced the woofer issue years ago too. I could even induce feedback in my system by cranking the volume. That lead me down the path of isolation and to my current turntable which I think, like many great turntables out there, provides a firm foundation for the spinning record.
I have also experienced the occasional record with built-in rumble that excites the woofers. Mostly, I do not have much of an issue because I simply do not play music at ear splitting levels like I did in the 70s and 80s. But for those that do- then solutions like a low pass filter are perfectly reasonable. For some of us purists, the idea of a filter risks missing out on some of the music. For example, an organist who uses the 16ft pedal to give his music a certain character. Or how about the cannon fire on Terlarc's pressing of the 1812 Overture. There's a test for your cartridge/tonearm. The grooves in the record make nearly a right angle turn! So hopefully, the low pass filter is needed only for those certain records with high rumble. I remember years ago playing one of my favorites, Dark Side of the Moon, cranked way up. The woofers were excited as soon as the needle was dropped into the grooves, but the most fun was watching them pump out the heartbeat. Bragging rights to those whose speakers could blow out a match. :) Of course, I'm much too mature for that now.
I had this same issue in my system....tore my hair out until someone suggested that it is some kind of RF...from airport, etc. I replaced my cables with shielded ones, and the pumping was gone. ...I'm not saying that is YOUR problem, but it was mine. the way, you CAN change the mismatch of cartridge/arm by adding weight to the cartridge end of the arm.
No, that's not that, I do listen to records but don't have such damn thing.
Just got a KAB filter and installed it. Much better!!!

One thing that is for certein is that many records are often not flat, but have minor warps that cause this great displacement of the woofers due to the low frequency. It's not the problem of the table, the cart, ot the isoltaion. It IS the record and the ONLY way to solve this is to use a low pass filter. It is down 3 dB at 18 Hz and continues down at a steep 18 dB per octave from there. This is not going to cause any negative effects. And bass is in mono anyway from 140 Hz on down and the filter also removes any vertical rumble in this region.

The KAB has in fact has tightened up the bass in my system. Highly recommended!
A rolloff point at 18Hz will cause phase shift up to 180Hz- IOW, 10X the cutoff frequency. The phase shift will manifest as a loss of impact, increasing as frequency is decreased.

This might not be all that noticeable if the speaker has an LF cutoff that is significantly higher than that of the filter! Smaller speakers, where the LF noise is outside the passband of the speaker, may well be particularly susceptible to woofer motion. We run some smaller monitors here that cut off at 40Hz and have not had any troubles with them at all, FWIW

We set our preamps up with about 2Hz rolloff, even in the phono, to avoid phase shift. We avoid woofer pumping by the proper combination of cartridge compliance and effective mass in the arm.

Not uncommon for warps or other imperfections in record geometry to produce subsonic rumble To some extent. Goes with the turf with hi fi phonos. resonance frequency of cart/tonearm can exacerbate the problem with certain combos more than others.

The biggest danger of this is that subsonic rumble uses power that is no longer available for music and clipping can occur sooner, impacting sound quality and putting drivers at risk, so be careful.

BEst solution is avoid records that have this problem too much as much as possible. Get a better quality copy. High pass filters are the common solution, but that is a band aid and effects on sound are usually noticeable.

Better yet, go digital. No subsonic rumble and other vinyl snafus there! :^). Digital can be very good for not much cost these days, much more so than in the past.
My Pro-ject Xpression III did this same woofer pumping issue. It was very noticeable as soon as the stylus hit the record before the music started. Same system, same table location, same cartridge, same phono pre, same high efficiency speakers (92dB Tekton 6.5t) and now totally gone now with a new RP6 (both tables were setup professionally by same shop). Was the motor vibration in the Pro-ject coming through the subplatter and platter.