Woofer pumping WHY??

Hello All, I have an older REL B2 series. I love this sub. I recently received a new Project Xtension 10 with Clear Audio Maestro Ebony v2. After a couple days I noticed bad woofer pumping on several records I like to listen too. When I brought it up to Needle Doctor they told me it was my records and said it worked fine in there store. Now my REL is blown! I am so upset at myself for not taking this matter more seriously. Now I am purchasing a KAB rumble filter because I am not going through this again. Is this a cartridge mismatch?? Because on my REGA with Dynavector 10X5 It did not do this woofer pumping nearly as bad. AND I do remember putting a DENON DL103 on my RB301 and this same woofer crazy action occurred!! Immediately took it off that arm. I just spent $4100 for this Xtension10/CA Maestro and now I am scratching my head. Hmmmm.
Ok now I am saying that its not a bad cartridge arm match because I am getting amazing sound from the main speakers. But I still have this rumble problem and the only way I know to get rid of it is to buy a rumble filter. Anyone have a highend turntable and experience bad cone movements?? I think these excessive cone movements might have damaged my REL'S voice coil?? Because now its making scraping sounds and I had to move it out of the system :-(
Did you check the arm cart combo for resonant frequency? There are on line calculators if u know the cart compliance and arm effective mass. At least I think it's effective mass.
The phono stage needs to roll off below 20Hz. Otherwise you're playing with fire, as you've observed. Some phono stages do, and others don't...but it's stupid not to.
A cartridge arm mismatch will cause that problem. The rule of thumb is low compliance cartridge, high mass arm and high compliance cartridge, low mass arm. You should get a test record like the Shure test record TTR 115 that can be gotten on Ebay for about $15.00. The ideal resonant should be from 8 to 12 HZ. Years ago I was blowing woofers until I corrected the problem and replaced my heavy arm with a lighter one.
You are getting rumble. You need a phono preamp with rumble filter. You can damage speakers without it. Too much acoustic feedback.....PT
Matt, when you play the records you referred to with the sub disconnected, do you see any visible indications of woofer pumping in the main speakers?

If not, it would seem likely that what is exciting the arm/cartridge resonance is not minor record warps, as is sometimes the case, but rather acoustic feedback from the sub. In which case some experimentation with sub placement may be in order. And possibly also with isolation provisions under the turntable, despite the statements in its literature about "perfect decoupling through magnetic feet" and a "mass loaded magnetic floating subchassis."

Also, while chances are it is unrelated to the problem (although it is conceivable to me that it might be), where are you connecting the ground (black) wire of the sub's Speakon cable? And does the sub have a 3-prong power plug? If it does, you should probably NOT be connecting the black wire of the Neutrik cable to a negative output terminal of the amp. And come to think of it, given the amp's "quad balanced" + autoformers design I'm not sure that the black wire should be connected to a negative output terminal even if the sub has a 2-prong power plug.

Sorry to hear, btw, that the sub may be damaged. But perhaps if the pumping issue is resolved it will no longer scrape.

Good luck. Regards,
-- Al
The tonearm mass is a low 8.5 grams ,the cartridge has a compliance of 15 (on the low side). That combination looks like a mismatch to me. You can try a headshell weight to add some mass to the arm and see if that improves the problem.
Get a KAB rumble filter for 189 and problem is solved. I had the same problem with my Scout turntable, I tried relocating the turntable to various locations and using all kinds of platforms under the turntable and nothing helped. Put the rumble filter on the tape loop and use it when playing records. All the oscillating speaker problems will go away. I hear no difference with the rumble filter in and out of the system. The only thing that changes is the woofer pumping: none with it on and all with it off.
I had a big woofer pumping issue

In my case we finally isolated it

The bearing in the tonearm wasn't moving properly so there was cyclic woofer movement as the cantilever took the brunt of the motion

We did a feather test suggested by Thom Mackris and that was it

A tonearm tune up and no more issues

One of my threads on it


What is your flooring type, turntable rack / isolation?
Is it more apparent on the outside grooves of the record?
Is it cyclic or keyed to loud passages or bass heavy parts of the music?

Search engine is your friend

I found 8 threads putting in the words woofer pumping
I have a B3, essentially the sames box, but you have the 12" woofer.
When I see my B3 looking like the woofer is going to jump out of the cabinet, usually means 1-system is cranked and the particular recording is "hot" on the low end, so gain needs to be turned down. I don't keep my sub at one supposedly "perfect" level. While it can be left alone for casual listening and not cranked, ALL recordings are different, so I adjust accordingly. I think REL got it right with the remote for the Gibraltor series.
The second is the actual record.iIf it isn't perfectly flat, when cranked, the movement of the arm over the warp is going thru the cart.
After countless sessions over the years, my REL permanently resides behind the listening position, about equidistant to the floorstnders.
All setups , rooms are different so my experience may not even apply in your setup.
Incidentally, my REL is on Mapleshade brass/slab which I've found not only a nice looking, but sonic tweak. Consider it, if you haven't already.
My floor stander have the same setup.
Ok I'm connecting the sub with the Spkon cable and all three leads to the back of the amp, Otherwise wont the amp then SEE the REL in the system? Before I got the new table I had been using the REL for quite a while with no problems ever. The REL is plugged in to the wall using a 3 prong cable (both the spkon and power cord are from Signal Cable). I do see the woofer pumping on the main speakers too, and this seems to occur more toward the outside of records im playing. The Sound is very very good. If that says anything. But this cone movement needs to be addressed. I'll do a little more troubleshooting and get back soon. Do a lot of vinyl spinners use outer rings?? I see that most of the HIGHLY re guarded phono preamps Don't have subsonic filters? Like my MS Phonomena. I don't think my phono stage is the problem. I respect every ones input thank you. Stereo5 you sound like my older brother..LOL that's what he keeps telling me. He has a KAB. Yogi, Wouldn't the sound be bad or unpleasant with a bad arm/cart combo? because the sound seems to be gorgeous! Al, Im using unbalanced cables to amplifier and my speaker cables are spades, the REL Spkon cable is Bannanas on amp side. I have a concrete floor with carpet. Salamander rack with Mega spikes. Yogiboy, I think is on to something, but the sound is so dam good? So I am perplexed.
Mattmiller,I standby that the cartridge arm combo is not a
good combination,and will wreak havoc. The sound is good
because the problem is in the subsonic region that you will
not hear. If you don't address this you will have the problem till
the cows come home. You should get the filter if you think
that will work and return it if it does not fix the problem. BTW,if
the NeedleDoctor tells you there is not a problem then he
should go back to med school ! You should get a test record
with the resonant frequency test. I use the Shure TTR 115
ERA lV,you can find them on Ebay for about $20 bucks. The
other fix is to get a higher compliance cartridge or an arm with
more mass.
Yogiboy , no doubt you are correct,used to see it all the time back in the day with heavy arms and HIGH-compliance carts.
Do you,or anyone else, have recommends for higher compliance MM carts readily available ?
Hi Matt, had the same problems after my Lyra Kleos was to repair. When i got it back the compliance was softer and i had this pumping. Look here Video

The deflection of the needle because the decentered records correlates with the woofer pumping.

No i have an EMT JSD6 which a lower compliance and on the loudest volumes no pumping.
Schubert, Ortofon,Grado,and some Soundsmiths all have medium compliance and will work with a tonearm that is from light to medium. I don't think they make super high compliance cartridges and super low mass arms that was the fashion many moons ago. I was kind of surprised that the arm the OP has was only a low 8.5 grams mated with a cartridge with a low compliance
Funny, I had the same thing going on for the past week with my vpi classic lyra helikon combo, freeked me out. I tracked it down to a recently installed network router/switch that was positioned to close to the system.
Matt, you've gotten lots of good inputs, but I see it a little differently than some of them. Based on the information Yogiboy supplied about the effective mass of the tonearm (8.5 grams) and the compliance of the cartridge (15, although I haven't been able to find an indication of what the units are for that number, which can make a significant difference), and also taking into account the weight of the cartridge (8.5 grams), it seems to me that if anything the resonant frequency of the combo is likely to be above, not below, the 8 to 12 Hz area or thereabouts that is generally considered to be ideal.

That will tend to reduce, not increase, sensitivity to most warp frequencies, and also to modulations caused by off-center records. What it will increase is sensitivity to very deep bass content that may be on the record. So my question is does the pumping issue manifest itself on most or all recordings and passages, or just on those that seem to have significant content in the bottom octave?

Regarding my other point about the connection of the sub's ground wire, ideally it should be connected to a circuit ground point on the amp, which in this case isn't provided. None of the 12 binding posts on the rear of the amp are at circuit ground potential, as can be determined by close examination of the wiring diagrams for the autoformers, as shown on page 14 of the manual for the MC452 (linked to on this page), which presumably is conceptually similar in this respect to your MC352.

In some cases the result of connecting the ground wire of a powered sub to a negative output terminal of an amp having balanced outputs can be severe hum, activation of protection mechanisms, or even damage to the amp as a result of having an output terminal bearing a signal shorted to ground. In many cases, though, fortunately including this one, the designs are such that none of those things occur.

However, looking at the autoformer wiring diagrams I referred to, I suspect (given that you appear to be using a single sub for both channels), that you are not providing the sub with a sonically optimal pair of signals. Specifically, it appears that half of the signal (either the positive half or the negative half, at any given instant) that is received by the sub from the channel to which the ground wire is not attached will actually be derived from the other channel. Which doesn't sound like a recipe for ideal sonics.

Although this is obviously not related to the pumping problem, since the woofers on the main speakers pump even when the sub is disconnected, at some point you might consider connecting the ground wire to a chassis screw on the amp. Depending on the internal grounding configuration of the amp and the sub, that may work fine (it does in many cases), or it may result in a lot of hum. (Doing that, btw, would necessitate increasing the sub's level control by about 6 db). Or you might even consider connecting the sub at line level, to the preamp, although to do that with your particular sub you would need the 12 db attenuator REL supplies (or at least used to supply) for use when a single sub of that model is provided with two input channels at line level, since its two line level inputs have gains differing by 12 db.

-- Al
Cartridge is 8.5g and Tone arm is 8.5g's, the frequency calc says 10...12 being ideal. So is this a bad match?? It says no. It seems to be in the GOOD RANGE. I AM GOING TO PUT MY dYNAVECTOR 10x5 ON THE ARM AND SEE WHAT HAPPENS. nEEDLE DOC SAYS THEY WILL LET ME SWAP FOR A DIFF CARTRIDGE I just want to make sure which one I should go with.
Breaking NEWS !! I think I'm getting really OLD because now I put the REL back in the system with my digital it sounds fine??? I am going to play some more vinyl and see if it still occurs, but for now all seems well again !!!
So I can sit there and see my system has a heartbeat. When I play any vinyl it goes 4 very quick beats then nothing then 4 very quick beats and so on... it even speeds up when I play 45's! WTF is going on ??? Its a brand new table. this HEARTBEART is in my main speakers and the REL. I am going to put my REGA back on the same input and see what happens.
That's absolutely what you should try. Let us know if the Rega table eliminates the woofer excursion. I'm dealing with the same issue, just since I recently installed a new preamp. I believe it must be the increased bandwith of the new Preamp. Best of luck Matt.
When I play any vinyl it goes 4 very quick beats then nothing then 4 very quick beats and so on... it even speeds up when I play 45's
Good observations, which lead one to suspect an irregularity in the new TT's drive or bearing system.

As a cheap experiment, you might try a different drive belt.

If you don't have a spare belt, try removing the one you have and feeling for irregularities. Sanding those lightly might help. Then reinstall the belt "other side up".

Try as many of these as you easily can and see if the woofer behavior changes.

I found a few phono preamps with 20hz rumble filters and bought one (Cambridge). Problem solved, but I do wonder if a higher end turntable would be rumble free, as the ultra low frequencies inherent in modern phono playback (and the wide frequency range of modern gear) matched with bass reflex speakers seem to make rumble. There doesn't seem to be any acoustic feedback in my current turntable system (which sounds great), so I suppose I won't know until I change the table someday.
i have never had a problem with Woofer pumping in any system. I have heard about this, but whether it was an entry rotel preamp and Dual 721, to my current RCM Sensor II Phono preamp, ZYX UNIverse II, Pass Labs Xp10 and XA 30.8 etc, just have never see this issue. Have you changed the cartridge to see if there is a special resonance you are coming up with?
"07-21-15: Dougdeacon
When I play any vinyl it goes 4 very quick beats then nothing then 4 very quick beats and so on... it even speeds up when I play 45's
Good observations, which lead one to suspect an irregularity in the new TT's drive or bearing system."

I have never had an issue like this, but amplifying on Doug's suggestion I would put a piece of painter's tape on the side of the platter and see if the pumping correlates with the tape location.

If that happens, and your Rega does not have this issue, you should call your retailer and have a more detailed discussion. It could be that you have a defective turntable and they should work diligently to help you resolve this issue, regardless of whether it is system based or a defective turntable.
Well with the REGA it dosent make the cyclic pumping action ( I still get a little subsonic pumping but not to bad). Im going to try a block of granite under the table, to increase self mass. Going from the REGA to the PRO-JECT was like lifting a veil off my system, I cant go back. I think the Project is picking up music from my system because everything is so close together in my room. Does that make sense??
Good followup suggestion from Jperry. I would try his simple diagnostic and my suggestions before schlepping a hunk of granite, which seems unlikely to alter the behavior last described.

Do whatever you like of course.
I don't have much faith in the "higher mass shelf theory" but Its easy for me to test that one. I really think the new Project Xtension 10 is not the problem. All the table has done is push a lot more music through the system than before. Also, made it a lot more sensitive to play vinyl. I have 2 cheap phono preamps and I think one is even going bad. So, there is a lot going on that's not good right now. This is very interesting to me also though. I am sure there is a resolution coming soon.
From your description of the woofer motion(four large excursions/stops/four large excursions/stops/etc); neither acoustic feedback or tonearm/cartridge resonance are your problem. As Mr J stated; you'll find it's mechanical(belt/bearing/platter). If it's under warranty, take it back.
I had woofer pulsing with my pro-ject xpression III. Went to a regs rp6 and no more woofer problems.
So, I received a large piece of granite from a good friend. I placed that under the TT and it really helped calm things down. I still get some woofer action, not always. I think it is in the records we play and the only way to really stop it is to buy a subsonic filter. I took the Pro-ject apart (to fix the cable connection) and put it back together again being super careful with the belt and everything. I was able to listen to music and it was awesome! I really want to thank all of you who have tried to help me trouble shoot this problem.

My phono section has bandwidth to 2 Hz but I don't experience excess woofer motion. A lot has to do with the match of the arm and cartridge.

But making sure the turntable (especially if it has no suspension) is properly isolated and also does not have a malfunction (in this case a main bearing that needs lubrication is the most likely problem) is paramount- you start there first.
Matt, Take a second look at your own logic in your post of 08/02. If the woofer pumping in your system were due to "the records we play", then a slab of granite placed under the tt could not have much effect on the problem, because the source of the energy that pumps the woofer is or would be endogenous. If the granite helps, then it is more probable that the speakers are positioned such that they are interacting with your tt by introducing mechanical energy that is vibrating your tt shelf via the floor, etc. So, the granite experiment might further move you to re-position the tt or the speakers in your listening room.
Lew, there doesn't appear to be much interest in logic here. ;-)

Matt posted earlier that his woofer pumping:

1. occurs with his new rig but not his old one.
This earmarks the new rig as specifically involved with the problem.

2. occurs on all records.
This eliminates "the records we play" as a culprit and points toward the (new) equipment.

3. occurs in the specific, repeating pattern of 4 pumps and a pause.
This eliminates both tonearm/cartridge interactions and "the records we play" as culprits, since either one would generate pumps in an irregular pattern based on the individual record.

4. occurs faster when playing at 45rpm than at 33rpm.
This suggests a defect in the TT drive system or bearing. No other elements in the vinyl playback chain are speed dependent.

Taking #s 3 and 4 together, the most likely suspects are a defective bearing, motor or belt. Any of these could cause "bumps" in a regular, repeating pattern that is speed dependent .

I pointed this out on 7/21. Jperry, Rodman99999, you and now Atmasphere have all reached similar conclusions. We've advised Matt on diagnostics and that he should consider filing a warranty claim on the new TT.

Aside from non-sequitars like schlepping granite, his only response was that the TT is new, so why would he need to file a warranty claim? This was irrational, so...

[insert .gif of dead horse being cruelly if amusingly beaten... 4 beats and a pause, 4 beats and a pause...]
I totally agree with your assessment. In fact, I think there may be two separate issues: (1) the inherent defect in the tt, and (2) some sort of room interaction that is partially ameliorated by the granite shelf. At least, these dual hypotheses are consistent with the info we've been given. I did not want to "push" further on problem #1 (see your "dead horse" analogy above), so I addressed only problem #2 in my last post, because Matt seems receptive on that one.
Use an outer record clamp to stop the low frequency causing the pumping...cheers
Use an outer record clamp
...says the man who sells about 40 different kinds...
Maybe not a dead horse, but a horses... You get the point!
LOL. Now this thread's getting some traction!

All I can say its about time!
@Doug- "The dead horse kicks, but doesn't even aim one at me?" You're not missing anything! OH WAIT....this thread's over(shame on me)!
I've been following this thread closely. It is so exceptional that I'm really surprised the moderators haven't included it in the "Best Of" category.