I had woofer pumping with my Pro-ject Xpression III. I tried both a Pro-ject phono tube box and a Jasmine LP2 mkII for phono preamps. I got woofer pumping with both preamps (the Pro-ject phono tube box had a subsonic filter, tried it in both postions, the Jasmine does not have a subsonic filter). I uses an Ortofon MC-3 turbo on the Xpression III. Once I upgraded the table to a Rega RP6 with same cartridge, same wall shelf and same Jasmine LP2 mkII, the woofer pumping was gone. I sold the Pro-ject gear and did not look back. Since you are using a Rega P3 with GT upgrades (I assume subplatter and acrylic platter), I'm not sure where to turn on this. I am using the factory RP6 subplatter and glass platter, but I just ordered a GT RP6 reference subplatter. Do you have a Rega dealer local? Can you ask to borrow a RP3 (either the whole deck or maybe the glass platter) to see if it reproduces the woofer pumping? Does anyone know if acrylic platters are prone to reproduce more woofer pumping (I thought they reduced vibrations) as the Xpression III and Matt's P3 both have acrylic platters?
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If you go to KABUSA.com and look up Rumble filter...They talk about how this is something that is recorded into ALL vinyl from the cutter head. Its subsonic rumble and it makes your amp and speakers do things that are not kool. My brother runs a VPI classsic with a Lyra Delos and he bought this device. He says it works wonders! I posted this thread because I have never heard anyone talk about this problem.
IME the most frequent cause of 'woofer pumping' is an arm/cartridge mass mismatch. This problem should be cured by proper matching and set up, not a rumble filter.
A rumble filter would help with sub-sonics that are present on the recordings. I've heard these on some British recordings where the studio was near an underground/subway. But I'm not so sure they are all that common. If you have a tape loop on your pre-amp you could stick one there and only use it when needed.
Dear Mattmiller: If we take care on the overall audio system each link set up usually we have no need for a rumble filter.
A rumble filter as any filter where the audio signal pass always degrade that signal in many ways and IMHO do more harm than help.
What we have to do is to revise the overall system set up to find out where it comes the feedback that makes the woofers moves.
++++ " So I am wondering why dont a lot more companys sell these things if they are so important? " +++++
because is no important as you can think. I repeat all resides to have a right overall system set up. Forget about rumble filters or any kind of filters. The audio signal does not needs to be filtered to avoid those woofer movements what that is telling you is that you have a problem in your system set up and that it's.
Of course that a filter seller always will tell you that you need it because that's how is taking money from you. With all respect all those satisfied owners of rumble filters are ignorant of what I'm posting here.
Regards and enjoy the music,
I am thinking that Rauliruegas AND Newbee have some valid points. This is why I do not want to buy one if I can help it..I think there is something wrong in my system...Today I am trying a completely different table and Cart..Thornes TD160 with a Nagaoka MM 4.0 output. Once I run some more tests I will re-post my findings....Thank you for the responses I agree that there is something wrong in MY setup that is causing this AND I am sure it has to do with Cart compliance and tone arm mismatching....more to come.
Well everyone has an opinion of course. Perhaps some might be interested in Harry Weisfeld's; he probably knows a bit about vinyl. Then again, maybe not?
Sometimes (actually many times) woofer pumping will not be the result of poor setup and sometimes (actually many times) a good subsonic filter is a very good idea.
You won't "hear" negative results with a good subsonic filter-quite possible though that you may hear the positive results of not having your woofers flap around in ways that they were not intended to as well as having all the power sucked out of your amplifier by the subsonic frequencies.
I'm sure there may be bad subsonic filters out there. The KAB is not one of them (IMO), having used it. I also like the subsonic filter in my phono preamp.
Dear Hdm: ++++ " he probably knows a bit about vinyl.... " +++
probably yes but I think he knows more on TT/tonearms and IMHO he is not so good on the subject onh this thread. It's an opinion with huge negative trade-offs.
++++ " You won't "hear" negative results with a good subsonic filter... " +++++
maybe you can't but I can tell you that many of us can hear it. Of course that if the audio system has a poor resolution or our ears are not trained then we can't be aware about.
Now, if you are happy with then good for you.
Regards and enjoy the music,
The subsonic filter on my phono preamp is -9 dB @ 10 Hz, -18 dB @ 5 Hz and -48 dB @ 2 Hz.
Not sure what you'd be hearing down there (at least in terms of anything good on the vinyl as opposed to the negative effects of both the amplifier and the woofers trying to reproduce it), but if you are, you are a better man than me.
My system is reasonably resolving, does not suffer from a tonearm/cartridge mismatch and my ears are pretty well trained after 35 years in this hobby.
Now if you are happy, then good for you too.
Enjoy the music as well.
I have noticed this as well, my phono stage (SimAudio lp5.3 and psx), has 2 selectable equalisation filters, RIAA and IEC. They are essentially the same, but the IEC filter roles off everything below 20Hz. I use this and have no woofer cone "pumping". I'm sure that excessive cone excursion, must interfere with how the cone reproduces the musical notes. I agree, I would be loath to put and extra component in the signal chain, with attendant interconnects and filter, but with it built into the filter that every cartridge has to use i'm happy to use it. I can't hear anything below 30 Hz anyway.
Dear Hdm: I think that if you take 10 persons with the experience you have and ask about their preferences on use a rumble filter or not use it you could get 9 answers that they don't use it and don't like it ( me between them. ), perhaps by ignorance.
I'm not against your prefrence because you are satisfied with and is you whom have to live hearing it.
Now, maybe I'm ignorant on the subject or I'm missing something or you know for sure something I don't. I would like that you can explain how is that a cartridge signal that pass for a rumble filter that is an additional electronic stage is not degraded ???? IMHO the best rumble filter is NO rumble filter, especially that in normal condition we don't need it.
If any one of us has a problem with those woofer movements and the system set up is correct then something on the audio system links is running wrong or exist a mistmatch in between or simple bad design item and in this case we have to change it.
I don't like to take an aspirin for a headache but is better to know why that headache coming and then fix it.
You like aspirns: good, nothing wrong with that. It's obvious that your music/sound priorities are different from mines that are to lose or add the less to the cartridge signal protecting its sensible integrity to be nearer to the recording.
Regards and enjoy the music,
For those filter advcocates remember that there are some amplifiers/preamps with " problems " in its design that suffer of low bass oscilations that could provoke those woofer movements.
As I said IMHO it's always better to fix the headache, that filter is an aspirin that really is solving nothing but degrading the audio signal.
No, I'm serious. I'd like to hear your explanation. If your speakers are fluttering trying to reproduce subsonic frequencies that go below the speakers' frequency range and cannot be heard to begin with, I'd like to hear a scientific explanation how you're degrading the signal by removing these frequencies from the signal.
Filters are bad because they introduce phase problems, frequency response anomalies above their bandpass, added noise to the signal, etc. Woofer pumping is bad because it reduces the dynamic range, introduces distortion, reduces transparency, etc. Which problem is worst depends upon the specific system, music preferences, room modes and listener likes/dislikes.
If the pumping is caused by cartridge/tonearm or turntable suspension/placement issues, then they should be addressed first before resorting to a filter. If the pumping is a result of problems inherent in the recording, then a filter is an optimal solution. As with all things audiophile, some filters are better than others.
BTW, one of the first things taught to audio engineers is bandwidth filtering. When recording an instrument you want to get rid sound below and above the frequency range of the instrument. It's considered a sign of a well engineered recording.
Dear Actusreus: probably you don't know how filters works so take a look on internet to learn about other that what Onhwy61 posted.
Now, we have a limited frequency range through our ears and obviuously that we can't be aware of a wider frequency range hearing what happen in that wider range but you have to remember that frequencies and distortions generates harmonics too that modulate the frequency range where we " live ".
If we have woofers pumping this is a system anomaly somewhere in the audio system and we have to fix it before try the use an " asprin ".
The analog medium is so imperfect that IMHO we have to take care not doing more " imperfect " creating higher distortions becuase that " asprin ".
Regards and enjoy the music,
Onhwy61, I was with you 100% until this:
BTW, one of the first things taught to audio engineers is bandwidth filtering. When recording an instrument you want to get rid sound below and above the frequency range of the instrument. It's considered a sign of a well engineered recording.Hmmm... did Kenneth Wilkinson use bandwidth filters on his 3-mike recordings of full orchestras for Decca? I doubt it. Are you suggesting his recordings weren't well engineered?
I've no doubt your statement is true for engineers being trained today. It's one more example of acoustics knowledge and skills being replaced by 47 mikes in 47 booths, a mixing board and a pile of resistors. The result is lifeless, over-processed crap. But at least it's crap with no out-of-bandwidth noise. ;-)
Dear Dinster: No, RIAA " filter " is not good and damages the audio signal.
In the other side a subsonic filter is not transparent because needs passive or active parts to function and the signal has to pass trough. Now, if the preamp design has it as an option then only damages when is swtiched on and when off ( if was designed that way. ) is out of the audio signal: the signal does no0t pass throught it ( insist, if was designed that way. ).
What I can't understand is why the posts of you are around the rumble filter instead to fix by origine the system woofer movements/pumping. IMHO, makes no sense.
Regards and enjoy the music,
This is your response? I thought you knew what you were talking about. Sounds like you're simply repeating your analog rhetoric without much scientific knowledge on the subject to back it up. Sorry, but that's not very convincing to me.
It seems to me that the audio signal is always necessarily "filtered" once that stylus and its motor assembly picks it up off the record surface. Open up your phono, line, and power amps and you'll see all sorts of "filters" such as transformers, resistors, capacitors, chokes, etc. I don't doubt that there are better and worse subsonic filter designs out there, just as there are better and worse amplifier designs out there, and I do understand the argument that fewer components in the signal path is more desirable. But after reading countless posts about rumble filters on this forum over the past several years, I still have not seen a convincing argument how a well-executed rumble filter degrades sound except for purist rhetoric. Onhwy61's post is a good start, but I'd like to see more informed responses.
The most popular rumble filter on the market is the KAB filter. It's supposed to be transparent and not affect the signal except for the undesirable ultrasonic frequencies it is designed to filter. I'd like to hear an educated opinion just how this filter degrades the audio signal besides adding another pair of IC to the path.
I have a carefully and properly set up turntable that sounds great, and the only difference between the phono preamp filter being on or off is that when it's on the woofers don't pump with subsonic crap and my tube amp's bias lights don't indicate wild voltage fluctuations. Absolutely zero signal degradation. Prior to this preamp I used a preamp with a built in phono stage and had to use line filters (Nakamichi...amazing little items no longer available) that also showed zero signal degradation. The fix is in!
Dear Onhwy61: Well, I think that my post needs some explanation because the inverse RIAA eq. is a " necessary evil ": analog can't exist with out it.
From that point of view, we can't do nothing to " by-pass " it.
IMHO the higher and worst cartridge signal degradation take form through that RIAA eq.. We are talking of a curve with almost 20 +,- eq. over the frequency range where at the end always exist a frequency deviation that preclude flat frequency response. We are near the RIAA recordedd curve but not mimic exactly.
I think that between other critical subjects both RIAA eq. curves are important part of the analog Aquila heel.
No, it has no relation with the thread subject.
regards and enjoy the music,
Dear Wolf_garcia: +++++ " Absolutely zero signal degradation... " +++++
no, I don't think so. The important subject here is that even with your: """ carefully and properly set up turntable """"
do you know from where in your system comes that " subsonic crap " that you experienced in your system? because if it's coming from your electronics then that " subsonic crap " is only part of the signal degradation because exist other " things " ( I can't find other word, my english language is very limited. ) generated down there that still affect the signal. In the other side your " tube bias " light's can't help because your unit has a bandwindt that starts at 15 hz that we can't assume as a subsonic one.
My take in this thread is not really about filters but to fix the problem from its origin. This is the only way to preserve ( in that regards. ) the audio signal integrity and the only way that that audio signal stay UNTOUCHABLE by anything.
Regards and enjoy the music,
Well, most of the problem comes from from the motocross profile of a record (I am not talking about the music in the groove) with per revolution warps and cross section undulations that cause the < 33.3 Hz rumble, and there is nothing that can be done to fix this in system optimization other than to avoid playing (most) records altogether. In my experience that is where almost all the pumping is coming from. Just watch a record spin with backlighting and you can see these inch-to-couple-of inches-wide undulations. That is where the rumble comes from.
I do tire of people telling me how my system sounds, but again, since I listen to things and judge signal degradation with my very experienced ears and not the opinions of fatuous psuedo experts, I can say there is nothing to be done with my thoroughly vetted turntable rig other than to replace it, or simply enjoy its glorious sound with filtered rumble and a clear, involving, highly musical result. Note to Raulgasbag...the LEDs on my amp, just like I said, do indicate extraneous rumble in concert with woofer pumping and both are calmed immediately by the well designed 20hz (obviously above the 15 hz bandwidth and 8hz frequency response specs of my amp) filter in the phono pre. Also note that any audio signal never remains "untouchable" unless it's off. Get it? And feel free to refer to a reputable online site for definitions of any English words you can't understand, such as "fatuous", "psuedo", and "gasbag."
Dear Wolf_garcia: +++++ " My take in this thread is not really about filters but to fix the problem from its origin. " ++++
that's what I posted. You don't care to fix it then continue to enjoy your " asprin ", nothing wrong with that because is you whom have to be satisfied: not me.
My opinion is only that the important opinion is yours because you are the one that must to live with the " asprin ".
Regards and enjoy the music,
A passive 6db/octave hi-pass filter, which could consist of a single low value/high quality capacitor in series with the amplifier input might be quite transparent. However, the cut-off frequency would have to be too high up into the audio range (guessing around 50Hz) to be effective at the very low frequencies for "woofer pumping". To implement an effective rumble filter that cuts in only at sub-audio frequencies, e.g., below 20Hz, I think you need a slope of at least 12db/octave or higher. Then, if you do that, you are looking at insertion loss, several components needed to get the steeper slope, etc. To avoid insertion loss, you might need an active filter. All of the above leads to loss of transparency and fidelity that can affect the entire audio range. So in this instance my bias is the same as Raul's. Less is more. But this is just "in principle"; I am not about to say that someone else's system cannot sound better with a well designed rumble filter vs without it.
Right now I am using a pair of Transmission Line woofers that I built several decades ago as bass support for a pair of Beveridge 2SW ESLs. (The 2SWs were designed to operate from 100Hz up.) Long ago, when I built the TL cabinets and used them subsequently, woofer pumping was always an issue because the woofer in a TL is essentially undamped by the cabinet. I am rather surprised that I see zero evidence of unwanted woofer motion, and I wonder whether the Dynavector tonearm I am using is more resistant to the problem than most.
Maybe it would be more constructive for Raul to say how to get rid of woofer pumping without a rumble filter. Since Raul (and others) have posted elsewhere that the interaction of tonearm effective mass and cartridge compliance can be disregarded with good results, would it be fair to say that mismatching those two parameters is a cause of woofer pumping and constitutes one instance in which we should pay attention to those hoary equations?
Warped LPs are an obvious secondary cause. But we don't play warped LPs very often, do we? (We are connoisseurs.)
Dear Lewm: I have no " all " solution on that regards because there are different focus where the woofer pumping can comes even an electronics severe subsonic osiilations.
I have not that kind of problem in my system but this does not means I have a precise solution because is system dependent. Many times the woofer pumping is not a very low frequency and I said " system dependent " because there are speakers that by design can't reproduce frequency below 30 hz.
Lewm, my take is that we have to fix the problem by origin but I never said it is an easy task. We have to test each audio system link because maybe you can't belive it but even an IC cables could increment the problem.
Regards and enjoy the music,
That's a reasonable answer. I think that even when there is not easily visible woofer pumping, "full-range" speakers can suffer a bit from the introduction of distortions that originate from extreme low frequency (sub-audio) signal that moves them around while they are trying to reproduce audio frequencies. I believe this represents your position, as well. So one solution is a sub-woofer or separately powered woofer. But that introduces new problems of integration and from distortions introduced by the necessary crossover network. There's no free lunch.
Dear Lewm: You are right, subs are a good answer and yes always exist trade-offs that in my case I decided for the powered subs trade-offs.
Now, in my system ( and you could make the same in yours. ) I have almost no trade-offs with the subs integration because I'm not using the usual crossover for my main speakers/amplifiers. An explanation of this:
my ML 20.6 monoblocks are coupled at the input by caps and what I did is to change the value of the input cap that along an input reistor ( by design. ) makes the high pass crossover with the advantage that that cap now is of a smaller value and the best teflon kind I found out. I don't have to modify the amplifiers designs but as a fact I improve it.
In that way the main speakers/amplifiers sees only frequencies from 78hz and up and below that crossover frequency the Velodynes takes the task wit its own integrated crossover.
I can tell you that works truly fine and with a huge improvement lowering the IMD in the main speakers. You need to test it this way and if you don't like it just come back to original status.
I know you have the knowledge and skills level to do it.
Regards and enjoy the music,
Raul, Yes, that's the way I would do it too. Use only a small value very high quality cap as a high pass filter in front of the amplifier that drives the upper frequencies. Then use a very high quality electronic crossover, with a steeper slope, to derive the low pass filter that drives the woofer amplifier. That's what I am doing with the Bev 2SWs, and I am very pleased. With a little fiddling, the crossover point is not audible. This is relevant to the topic, because by introducing the separate woofer/subwoofer, one is removing any rumble distortion from the main speakers without having to resort to a "rumble filter".
And yes, the success of that set-up has me thinking about adding a subwoofer to the Sound Lab system.
Rumble is one form of low frequency noise produced by turntables themselves. USing a good table ( I prefer belt drive) and keeping it in good working order goes a long way towards minimizing any impacts from rumble these days, it seems.
Warped and poorly cut and centered records are another common source of low frequency noise associated with vinyl record playback.
Resonance inherent in all turntable systems compounds the problem to various degrees depending on setup.
I've used high pass filters in the past on occasion to reduce low frequency noise associated mostly with certain vinyl playback cases, and tapes as well to a lesser degree, but low frequency noise is not a noticeable issue for me currently with any source I use, including vinyl. So I no longer use one.
Part of this is because the drivers in the speakers I use mostly are enclosed in a metal mesh can and abnormal incursions can not be seen, only heard. They handle whatever is thrown their way effortlessly and there is never any sign of audible stress to be detected.
Not the case as much with my smaller monitor style Dynaudio speakers, but even those handle most things fairly effortlessly.
Another part of this for me is I use a very robust and powerful amplifier these days that has plenty of dynamic headroom available to help effortlessly handle whatever is thrown its way.
I also have an even smaller pair of Triangle monitors. Those are much smaller dudes and will tend to show signs of any stress a lot sooner than the other bigger boys.
Rumble used to be more of a problem for me years ago when my system overall and turntable specifically was of lower quality and not as robust and resistant to effects of low frequency noise associated with vinyl playback in general.