Why the woofer moves badly when playing certain LPs


Hello. First greeting.
My turntable is Pro-Ject The classic, Phono is Lejonklou Gaio2.4 and Cartridge is AT150sa.

However, I am having problems with my woofer moving badly when playing certain LPs.
Generally, this is not the case with the older, dusty LPs of the 80's, but rather with the record just new released LPs.

I want to get help from someone who knows why this is happening.
Sorry for my broken English.
Thank you very much.

starbusters
Hi Starbusters, many lacquers are now cut on old poorly maintained lathes. They can produce prodigious amounts of rumble coming from both the main bearing and the worm drive of the cutter head. This will cause your woofers to bounce around and even bottom out. With most speakers the rumble is so low down you won't hear it and if you have grill cloth on your speakers you might not even notice it. In my case having four large subwoofers the whole house shakes. I have already sent three records back this year alone due to this problem. It can be made worse by poor tonearm/cartridge matching but I do not think that is your problem. At best this robs you of power and Doppler distorts everything else the woofer carries. At worse it makes you whole house shake. When you get a record like that send it back and complain. Unfortunately, most people do not recognize this problem so do not complain. 
Actually, many of the lathes now being used have been rebuilt (having been recently rescued from years of storage) to better-than-new condition. Your problem may be that modern mastering avoids the use of the bass filtering that used to be common practice: rolling off the very low frequencies contained in a recording so as to make groove tracking by cheap, mass-market cartridges less demanding. Some current phono amps (Herron for one, I believe) include a rumble filter.
@mijostyn  I highly doubt that mastering lathes are to blame- too much is at stake! I have yet to buy a new LP and run into anything like this; OTOH many of the new LPs I've bought seem to have deeper bass than many of the older LPs (I like electronic music...). I did run into one LP which was overcut, causing distortion on bass notes, but overcutting is simply a mastering error on the part of the mastering engineer. 
One fairly simple explanation for the complaint is the cartridge has compliance too high for the mass of the tonearm.
Have you looked at the records to ensure they don't have any warping, or that they are sitting flat?
You are getting the woofers pumping due to feedback.  The stylus is picking up the airborne sound and re-amplifying it.  Either relocate your turntable, try different platforms and if all else fails, buy a KAB Rumble Filter for $179.00 from KAB. That is what I had to do and now I am a very happy camper. 
Welcome starbusters to the whacky world of analog playback, where everyone has a theory and the laws of the universe believe it or not actually allow all the seemingly conflicting theories to be right. Is it right to leave the dust cover on? No. Except when it is. Or yes- except when its not!

Are you even having a problem? Yes, if it bothers you. No, if it doesn't. A certain amount of very low frequency woofer excursion with records is perfectly normal. Its also perfectly normal that some records are better than others. Not just in this but in every conceivable way. Sorry, ESL, conceivable means every way you can think of. 

There's things you can do to have less. stereo5 mentioned acoustic feedback which he should know is not what you have but remember the whacky universe he is right its something that can be a problem. Just not in your case. Also probably not in your case is record warp. Really obvious warp you can see. Less obvious is dips and bumps that are hard to see. But it doesn't take much, a tiny invisible dip when amplified comes out a half an inch at the woofer. Sometimes a record clamp might help.

Sorry but you just never know. That's why you get five, ten different guesses. Any one or all of them could be right. Or wrong.

Only way to know for sure is to learn by trying. If the woofer moves a lot but doesn't rattle the house and doesn't bottom out the voice coil I recommend write it off as just another one of vinyls many charms. Or you could complain and try another record. When two or three all play the same you will learn. Or if the next one is better you will learn that too.

So much more fun than boring old CDs don't you think?
millercarbon
... A certain amount of very low frequency woofer excursion with records is perfectly normal ...
Perhaps it’s "normal" for your system, but that needn’t happen in the absence of a signal and if it does, you’re wasting amplifier power and introducing distortion. My system is flat to below 20 hZ and I have no such problem, but I also pay a lot of attention to phono setup and matching phono cartridge to pickup arm.
I used to get a lot of woofer pumping when I had a suspended deck (Manticore Mantra) but not when I went for one with a bit more mass ( Townshend Rock 2). At the time of the Mantra I had a pretty basic Sansui amp (AU217) and mission 700s and with those the pumping didn’t seem to effect the sound.
A certain amount of very low frequency woofer excursion with records is perfectly normal.
Just to be clear, my signal chain has 2Hz response from the cartridge input all the way to the loudspeakers, which employ dual 15" drivers. I run them without grill cloth covers and I only see excursions on things like big bass drum whacks. It takes a pretty warped record to set them off. But I was careful to make sure that my cartridge and arm work well together.


The cartridge in the arm has something called 'effective mass'. The cartridge also has a compliance figure; that in tandem with the effective mass creates a thing called 'mechanical resonance'. These things can be calculated by the way... anyway, the mechanical resonance should fall between about 8-12Hz; if it does than minor record warp won't be bottoming out your woofers. When the mechanical resonance is not in the right window, Bad Things happen- like mistracking, even to the point of the stylus jumping out of the groove, woofers pumping, breakup during complex passages and so on.
@yeti42, a Townshend Rock 2? Congratulations on your good taste! ;-)  Another of those superior designs ignored by the majority of audiophiles, @slaw (Rock Mk.7) and myself (Rock Elite Mk.2) the rare exception.
Ralph you need to come to my house and I will demonstrate. Most of the bad records are coming from the likes of Warner. The lathe is the only mechanical step in the process now. So it is the lathe by default. When I first got one of these records I thought my turntable was shot. I put another record on, quiet as a mouse. Since then I must have returned at least 20 records for this problem. I may be a bit more sensitive to it because my bass goes ruler flat down to 18 Hz then rolls off at 80 dB/Oct (digital filter). You will notice that Starbusters only notices this with NEW records. Not old ones. It therefore could not be a cartridge tonearm miss match. Until about 10 years ago I had never had this problem. So I am waiting for anyone else to give me a more logical explanation. 
Other than both Starbusters and myself being head cases. Geoffkait, keep your mouth shut.
Ralph the 18Hz is as measured. I use room control.
^^ My speakers are about 3dB down at 18Hz. We're on the same page with that one....
Mike I'm sure is right about the lathe and stuff. Yet more evidence to throw on the pile of reasons why with records you're better off buying old than new.

Mine, for the record (heh) move hardly at all. But they do indeed move "a certain amount".
Absolutely mc. Mostly with small warps and surface irregularities. Not all new records are bad. Some are terrific and there are several companies that consistently put out great product. I can't remember having trouble with built in rumble in the past but I certainly had a lot of trouble with noisy pressings particularly with popular music. Classical pressings were always much better. Rock was hit or miss. I have some old DECCA records that are astonishing. 
No one has mentioned the fact that reflex loaded speakers go nuts when driven below their tuned cutoff frequency. Does the OP have vented or sealed? He doesn’t say and our experts don’t ask. But the observation that this phenomenon is limited to new releases is suggestive that  we are dealing with a software anomaly and not a playback system misbehavior. 
Thank you very much for many feedback.

I'd like to make up a little bit more. This phenomenon does not necessarily appear only on new records.

For example, one of my old LPs is Eagles "One of The Nights," and one of the latest LPs is Weyes Blood "Titanic Rising," PHOBE BRIDGERS "Stranger In The Alps," especially on track 1. The woofer moves loudly even in the silent section before the music starts.

Most LPs play very normally, but this is happening in some records, so I want to know why. I didn't want to see this uncomfortable woofer if I could.

In the evening, I will upload an additional video of this phenomenon to YOUTUBE.
Years ago I had the same problem . It was an arm and cartridge mismatch. You need to know the mass of that tonearm and the cartridge compliance. If you do the calculations this chart will show the resonance frequency of that combination!
http://www.mh-audio.nl/Calculators/RF.html
I have recorded that was causing the problem and uploaded it to YouTube.

https://youtu.be/2tIc9_Ym6DM
What’s your speakers ?
Did you ever check phase, polarity etc ? Are you sure everything connected right from the cartridge to the speakers ?


That is crazy! Does your receiver have a rumble filter on it? My old Yamaha R900 had a button for "Sub-Sonic Filter" which was supposed to take care of the really low frequency stuff coming off records. I have not seen this on modern gear though.
-Geoff
/ chakster
Speakers are Canton Ergo620
As far as I know, I don’t think there’s any problem with cable connections, the attachment of cartridges, or parallel adjustment. Because there are LPs that are very normal and have great sound like the link below.
https://blog.naver.com/zuropa11/221839468237
At 0.49 I can see a large gap under the record at the edge. Approximately 1-1.5" of the outside of the record is not touching the platter. The record is warped. That is likely instigating your woofer excursion. If you have a resonance issue in addition as described by atmasphere, above, that will make it worse.
It sure looks to me like a stellar example of pickup arm/phono cartridge mismatch.
Use of a Subsonic filter or a preamp with one built in is almost a MUST when playing LPs. Subsonic filters were created specifically to remove that low end rumble and they work well. Just my two cents worth.
mhmeyers
Use of a Subsonic filter or a preamp with one built in is almost a MUST when playing LPs.
Such filters are necessary when there is such a profound pickup arm/phono cartridge mismatch, as in the example shown in the linked Youtube video. If the OP’s cartridge is not a mismatch for the pickup arm, then there is something amiss with the cartridge itself, such as its suspension. I think it’s preferable to treat this problem at the source - in this instance, by selecting a cartridge properly suited to the pickup arm - rather than subject the signal to a filter.

I play LPs and have no issues with woofer pumping, even on warped records, and my system is flat to below 20 hZ. But my phono cartridge is matched to the pickup arm, and I’m meticulous with setup.
Your woofer is playing the warps and surface irregularities. All that is certainly less than 10 Hz. That arm does not look all that heavy and I would think the AT would do fine in it. If you want to know for sure you have to get a Hi Fi News test record which has both vertical and lateral resonance bands and you will be able to determine exactly where your resonance frequencies are. If they are below 8 Hz you have a miss match and Ralph is correct. It could still be rumble from the lathe in which case your resonance frequency will be above 8 Hz and it would be the only possible explanation. But if it were rumble I would think you would also hear something as there are components in rumble above 18 Hz as the rumble I am talking about in certain records is more than audible and I also never turn my filter off. There is certainly a fault in those records as you say many do not do this. If you do not have a miss match the only solutions would be get a subsonic filter or don't play those records.
I use a digital brick wall filter at 18 Hz as I have an 8000 watt subwoofer system and at the volumes I frequently listen at I would probably launch woofer cones across the room. Actually what happens is the voice coils hit their end stop and make a very disconcerting bang. Without the filter you can't hear anything down there the house just shakes and you waste a ton of power until the voice coils bottom out. IMHO anyone who listens to vinyl and has a subwoofer system needs a subsonic filter. Even if they have a properly set up tonearm. Unfortunately in the analog world this is impossible to do effectively  without attenuating the bass or causing sonic degradation. But in the digital world it is no problem. What ever degradation is caused by digitizing your phone amp is more than made up for by digital bass management and room control. 
mijostyn
IMHO anyone who listens to vinyl and has a subwoofer system needs a subsonic filter.
Why?
Why not treat the problem at the source?
Cleeds, have you actually impulse tested your system and looked at the frequency response curve? Are you using digital room control? Being meticulous with setup is very important and it will certainly help but even if you have your tonearm set at say 12 Hz there is still going to be plenty of rubbish below 10 Hz that is going to get through. With the volume high enough everybody's woofers are going to flap at least a little unless they have a filter and in analog it would have to start rolling off at about 30 Hz.
It is true that sealed systems will flap less than ported ones because pressure does not build up within the enclosure. 
This may well not be a case of rumble in the record as I previously thought but there is certainly an element of record quality here and speaking from personal experience there are many modern pressings with rumble built in. 
Audio Technica AT150Sa
Weight 8.0g,
Static Compliance 40 x 10-6 cm/dyne,
Dynamic Compliance 10 x 10-6 cm/dyne (100Hz)

Pro-Ject the classic turntable
Effective Arm Mass: 13.5 g

Resonant frequency of arm/cartridge: 7.5Hz

Look like arm/cartridge mismatch is the problem !
mijostyn
Are you using digital room control?
No.
... even if you have your tonearm set at say 12 Hz there is still going to be plenty of rubbish below 10 Hz that is going to get through.
Not so. Not even close.
I understand that this will be a problem in many systems, and that a rumble filter may be the only way to fully correct the problem in those cases. But to insist that "plenty of rubbish below 10 Hz" is going to reach the woofers in every system and is an inherent problem in LP playback is simply false.
With the volume high enough everybody’s woofers are going to flap at least a little unless they have a filter ...
Nope. Not in my system.
Hello starbusters,

That is a classic example of a bad record. If your problem is only with certain new records, and does not happen with old records, then very probably your system is ok. That to me looks like a pressing error of the record. On the video, towards the end, it is obvious that record is warped... Bad production of the record mechanically... Not much that you can do there...Subsonic filter may help, but only to a certain degree...
Hope this helps.. 
Audio Technica AT150Sa
Weight 8.0g,
Static Compliance 40 x 10-6 cm/dyne,
Dynamic Compliance 10 x 10-6 cm/dyne (100Hz)

Pro-Ject the classic turntable
Effective Arm Mass: 13.5 g

Resonant frequency of arm/cartridge: 7.5Hz

Look like arm/cartridge mismatch is the problem !

@imhififan


If AT’s compliance is 10cu @ 100Hz you have to convert it first to 10Hz and it will be about 17cu @ 10Hz (Mid Compliance).

13.5 (tonearm mass) + 8g (cartridge weight) = 21.5g and you can add hardware too, probably 23g total.

The you can cross the lines (17cu and 23g) and it will be around 8Hz which is OK according to Ortofon:

Resonance frequency can be calculated by using the formula


f = 1000 : (2 x π x √ (M x C)) where:
f - Cartridge resonance frequency in Hz
π - 3.14159265359...
C - Cartridge compliance lateral in µm/mN
M - Total tonearm system mass which is a sum of Mass of cartridge, Mass of headshell and screws and Effective mass of tone arm (all values in gram).

• Resonance frequency within 7-12Hz is optimal for the system.
• Resonance frequency slightly outside optimal interval 6,5-7Hz and 12-14Hz can be considered as a possible that probably can be used without problems.
• Resonance frequency outside the interval 6,5-7Hz and 12-14Hz is questionable, and the system might not work properly.



The OP could use the lightest possible mounting screws to reduce the mass slightly. Or to remove stylus protector on AT if it's possible (to reduce the weight of the cartridge). 

Or to find a slightly lower compliance cartridge for that tonearm, for example a cartridge with 15cu @ 10Hz like Pickering XSV/3000SP will be a perfect match if we will check this (the resonance will be in desired range for 15cu compliance and toneam/cartridge mass near 21-23g).

BUT some people does not care about resonance frequency at all, here is the thread about it.




If AT’s compliance is 10cu @ 100Hz you have to convert it first to 10Hz and it will be about 17cu @ 10Hz (Mid Compliance).
I just estimate and simply doubled it to 20 @ 10Hz for calculation.

Resonance frequency within 7-12Hz is optimal for the system.
I'd like to have 8-12Hz as optimal value.
As you can see even +/- 3cu is important, but it's not that bad with OP's tonearm and his cartridge
From viewing the YT video, it appears to me that the arm/cartridge combo is just barely outside of the optimal range and this is borne out by some of the posts above. The thing about this is a slight amount of record warp can really affect the setup a lot more- leading to some LPs being quiet and others not. This being a smaller speaker (I was unable to find if it was ported or not) the woofer is going to flop around quite a lot with out-of-band signals.


The idea of going to lower mass mounting screws is a good one (worth a try- its cheap; maybe also remove the stylus guard), better yet a cartridge with slightly lower compliance.
Put the speaker grilles back on. If you can't see them pumping it can't bother you. (Only partly tongue in cheek).
I remember when I was young, but I never faced this phenomenon when I played pirated LPs on a cheap turntable. Even if this is the case with certain LPs, I don't think this is the only cause of LPs pressing.
A lot of people have given me good advise, and especially I'm going to focus on the rumble and try to solve this problem.

I'm sorry for not being able to thank everyone who gave me good advice
Thank you very much.
I experienced exactly the same thing through my ProAc D38's, the woofers would flap about all over the place without producing anything audible. My phone preamp has a subsonic filter, engaging that sorted it out. I was reluctant about the idea of a filter at first, but I couldn't detect any audible change to the sound quality so was more than happy to leave it on. 

The idea of going to lower mass mounting screws is a good one (worth a try- its cheap; maybe also remove the stylus guard), better yet a cartridge with slightly lower compliance.

A cartridge with lower compliance (15cu) that i mentioned also has light mass itself (5.5 - 6.5g instead of 8g AT). Could be an ideal solution if the OP's problem is cart/tonearm resonance.

@starbusters look at Pickering 3000/SP:

Stylus Type: Nude Stereohedron
ORIGINAL STYLUS: D3000SP
Compliance: 15cu @10hz
Contact Radii: .0028 (71u)
Scanning Radii: .0003 (8u)
Stylus Tracking Force: 1 gram (+1/2g) (-1/4g)
Setting with Brush: 2 gram resulting operation tracking force 1 gram. Optional range is (+1/2g) (-1/4g)
Frequency Response: 10 Hz to 30 kHz +
Output: 5.0 mV
Channel Balance: Within 1 dB @ 1kHz
Channel Separation: 35 dB @ 1kHz
Cartridge DC Resistance: 600 ohms
Cartridge Inductance: 350 mH
Cartridge Color: Brown
Cartridge weight: 5.5g (6.5g with brush)
Load Resistance: 47-100k Ohms
Load Capacitance: 275 pF
SP version was made in 1989, discontinued in 1994
Cleeds, since when is a resonance point a "brick wall" situation. The resonance peaks then rolls off. If your woofers do not move at all visibly and you are playing vinyl either your woofers do not go down very low or your cartridge is too stiff for your tonearm and your bass is rolling off prematurely. I suppose you could also be listening at the volume of a mouse squeak. I would never use an analog filter. It would damage the bass too much but digital is a whole other world. I could survive without it but volumes with certain records would have to be limited and It might rob enough power to affect the room control function. There are no downsides to a digital filter up to 80 dB/oct. With a 3 dB down point at 18 Hz the effect is totally inaudible. 
The problem Cleeds is that the source is vinyl, a medium that is imperfect at best. So, treating it at it's source means not playing records.

You need a 6/9 dB per octave (the higher the better) subsonic filter at around 18Hz.  Very unlikely you will hear anything below 25Hz anyway (more \like "feel it" but that will take care of it.
I see a periodic pattern in the woofer oscillations: every so often there’s a slight pause or dip in the amplitude of the oscillations and then the pattern repeats. The video doesn’t allow a precise clocking, but the pattern repeats roughly every 2 seconds. Given the observed warp in the record, I’m going to speculate that the pattern repeats 33 1/3 times per minute. Rather than an instability at the tonearm/cartridge resonant frequency, my guess is that the warp is triggering a tracking error in which the cartridge "bounces" along the groove without loosing contact altogether. This would imply suboptimal reproduction at all frequencies, not just the observed woofer misbehavior.

If this theory is correct, a rumble filter or adjusting the tonearm/cartridge resonant frequency would not correct the tracking problem (although I expect the latter would alter the frequency of the bounces). A first test of this theory would be to observe the woofer and count the number of pattern repetitions in one minute (should be about 33). A further test would be to increase tracking force and see if that reduces the amplitude of the woofer’s oscillations (might not eliminate them). Beyond tracking force adjustment, you might try adding a peripheral ring record weight. That should significantly flatten this relatively modest warp and add some extra flywheel stability to your rig.

BTW: Adjusting tonearm/cartridge resonance is worthwhile in any case.
If this theory is correct, a rumble filter or adjusting the tonearm/cartridge resonant frequency would not correct the tracking problem (although I expect the latter would alter the frequency of the bounces).
This statement is incorrect. If the mechanical resonance is corrected the amplitude of the woofer movement will be decreased. Making the LP flatter would certainly help, but is a more expensive solution (although it probably would sound better for other reasons such as improved control of the resonance in the LP itself) than simply reducing the mass at the end of the tonearm.
I am not a big fan of periphery clamps. It is a lot of extra weight on your platter's bearing and they are a PITA to use. Vacuum or reflex clamping are better solutions. Vacuum will remove some of what we are seeing but not all of it. Starbusters, get one of these  https://www.musicdirect.com/analog-accessories/hifi-news-test-lp-producers-cut
and tell us what your resonance frequencies are. This could be a great learning experience. If there is a miss match here it will be fun to see how correcting it changes your woofer flap. 
mijostyn
Cleeds, since when is a resonance point a "brick wall" situation.
I’m not aware that any person has made such suggestion, so it’s not clear why you’d ask that question.
If your woofers do not move at all visibly and you are playing vinyl either your woofers do not go down very low or your cartridge is too stiff for your tonearm and your bass is rolling off prematurely.
No, my system has no problem at all reproducing low bass from LP; it's flat in-room to below 20 hZ.
I would never use an analog filter ... There are no downsides to a digital filter up to 80 dB/oct. With a 3 dB down point at 18 Hz the effect is totally inaudible.
Given that the manufacturer of my phono preamp specs it as being within .2 dB of RIAA at 10 hZ, and down 3 dB at .3 hZ, why would I add a rumble filter in the absence of rumble?? I’d rather have an LP playback system that doesn’t require such a filter, be it analog or digital.
The problem Cleeds is that the source is vinyl, a medium that is imperfect at best. So, treating it at it’s source means not playing records.
That’s the logical error known as argumentum ad absurdum. I’m not going to stop playing LPs because the medium is imperfect, or because you insist that I need a rumble filter.
@mijostyn I generally agree with your criticisms of periphery clamps, especially the inconvenience factor. That being said, it's possible to select a p clamp that is heavy enough to flatten many warps yet light enough to prevent adverse effects on the bearing. I used to have a modest Clearaudio table with a CMB magnetic bearing. I added a relatively light p clamp, and it generally improved sound, especially timing, including with flat records. Heavier clamps would have caused the magnetic bearing to bottom out; that was the limiting factor for clamp weight on that bearing design. I never detected or expected any adverse effects on the CMB bearing, and inconvenience aside, it was a good improvement for that table.

I agree that reflex clamps are a better solution for flattening warps, but they are not easily available to the OP w/o an expensive upgrade. In fact, my current table is a fairly expensive model with a threaded reflex clamp (if I interpret that terminology correctly). I have no experience with vacuum clamping systems; their complexity and noise issues, though perhaps manageable, scared me off.

I became quite skilled at quickly positioning and removing the periphery clamp on the old Clearaudio, but I must admit I don't miss that ritual at all.