At what vol level do you get rumble / flutter?

Now that I got my new rega RP6, the woofer pumping issue is gone. :)

Hi Sbrownnw,I haven't compared specs, but this is a very popular regulated switching power supply.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=120-532

Not all records have built-in rumble, and even a cu/arm mass mismatch, tends to be dwarfed by acoustic and mechanical feedback, causing pumping. Spikes mass couple to the mount. Perhaps if you decouple your table from the shelf, it will help. That is another shelf under the table and supported by inverted cones. If you've already done this, sorry I missed it.
Regards,

Point of order. Effective mass of the tonearm is really the moment of inertia of the tonearm. The moment of inertia is calculated using I=mr^2. That means if you switch the mass of the counterweight and do not move it then the moment of inertia will change proportionally. If you must move the counterweight in or out, the moment of inertia is going to change by the square of the distance.
The angular momentum is I times rotational speed or like mv in linear terms. Angular momentum affects how quickly the tonearm moves or reacts to force changes. The force changes come from the stylus to record and through the suspension system of the cartridge
That means the natural frequency of the tonearm cartridge system is dependent upon its inertia, or effective mass divided by the spring rate of the cartridge and then the square root of that.
Long story short, change in counterweight mass as well as moving the counterweight in or out will change the Fn of the system. A lighter cartridge reduces mass and also allows you to move the counterweight in. So effective mass of the tonearm/cartridte goes down. If the spring rate of the lighter cartridge is lower (higher compliance) then the overall system natural frequency may remain nearly the same.

07-18-12: Sbrownnw
@johnny, my table is at my dealer now. It has the lighter 65g counterweight for cartridges between 4-7 grams. How do I calculate the effective tonearm mass with this lighter counterweight (10g lighter that the factory 75g for 7-12g cartridges). I might have him put in a pair of 1 gram brass screws to bring the weight up a little.

The change in counterweight doesn't change the effective mass of the tonearm. Effective mass is only the weight of the tonearm from the pivot point forward to the headshell. Once the cartridge is mounted, total effective mass includes the effective mass of the tonearm plus the headshell if removable, the cartridge, and mounting hardware. Standard mounting hardware is about 1/2 gram. Since cartridges have a wide range of weights, you use a heavier counterweight to balance a heavier cartridge. The heavier cartridge increases effective mass; the heavier counterweight does not; it simply enables you to get the desired tracking force from a heavier cartridge.

I added a pict of my entire system (on my system page) to show the config. Turntable is in the upper right corner.

I forgot to mention my turntable is on a custom steel wall rack bolted to the studs in my house but is in an audio cabinet (no doors). The section of the audio cabinet that houses the turntable has some of the back panel removed so the steel rack arms can come through. Could my problem be caused by this setup?

BTW, I put a new Vincent Pho-8 up against a new Pro-ject phono tube box II (my demo one was replaced under factory warranty after 1 channel got noisy) this weekend. The Pro-ject won out with better sound stage, realistic instrument sound and just overall more musical. I hope to upgrade the wall wart for the Pro-ject tube box. Would this one be a higher quality less noisy power supply?:

http://www.powerstream.com/EA1050.htm
EA1050A-61 16V 4A 5.5x2.5x11mm $57.50

Thanks everyone,

Scott

@johnny, my table is at my dealer now. It has the lighter 65g counterweight for cartridges between 4-7 grams. How do I calculate the effective tonearm mass with this lighter counterweight (10g lighter that the factory 75g for 7-12g cartridges). I might have him put in a pair of 1 gram brass screws to bring the weight up a little.

I meant to mention it in my last post - if anyone saw Fremer's "21st Century Vinyl" DVD, there was a great segment shot at Stirling Sound in NYC, and interview with the recently deceased, great George Marino. (What a loss to the community, by the way. Left us way prematurely. RIP George.)

Stirling uses a Neumann lathe to cut the master disc, and Marino was explaining the importance of isolating the lathe as it's essentially a turntable with a cutting "stylus," and any extrinsic noise can easily get transferred through the cutter and be embedded in the disc together with the recorded sound. They have the lathe on a slab of concrete and spring suspended. Even with this, I'm not sure you can isolate anything in Midtown Manhattan where Stirling is located, and it is certainly possible that many cutting lathes are not perfectly isolated and thus some of that unwanted low frequency noise does make its way into the vinyl.

If you can see the woofers pumping, then I would say that they are probably cycling at 0.5 Hz to 2 Hz. Note that 33 1/3 rpm is 0.56 cycles per second. So record runout, as I like to call it, ie. the eccentricity of the record grooves to the spindle could be generating a 0.56 Hz cycle. Some cartridges may mechanically filter out this low frequency side to side motion and perhaps some don't. Just a thought...

Actusreus,

I do see your point, I probably didn't read your post above.
Like you say, it is probably a combination of factors at work here.
From memory the cartridges i mentioned above produced 'nervous' woofer pumping even on nominally flat records. They were verging on out of control with any ripple like warps near the start of the record - hence I found them unusable in that setup (and I returned them).
I suspect, for whatever reason, they had very pronounced resonance which was 'set off' by any subsonic content.

BTW, thanks for your kind words on my audio page, not sure its as deserving as you make out, but thanks.

Tobes,

The existence of woofer pumping is not a debatable issue and I didn't claim you tried to dispute it. But I do disagree, at least somewhat, with your proposition that "[t]he sub-sonic frequencies are generated by the playback process but probably not by music content." It is not that it is done intentionally, but my understanding is that it occurs during the lathe cutting process. So it's not "recorded" but imparted during the cutting of the master disk. I'm not sure whether my example was clear enough or whether you gave it any thought, but given the differences in the degree of woofer excursion with perfectly flat records, I simply do not see how you can argue that the subsonic frequency is not present in the recording itself (well, in the vinyl to be more precise). How else would you explain the difference?

I certainly agree that it can be caused by the mismatch or acoustic feedback, or can be exacerbated depending on certain characteristic of the cartridge itself. Or turntable placement. I just think the phenomenon is more complex that many make it out to be.

By the way, I really enjoy your audio page. The pictures are superb, and there is lots of great information. I especially enjoyed your account of the making of the sand box. Well done.

07-07-12: Actusreus
I understand it's marketing as well on KAB's part, but I certainly noticed differences in the degree of woofer excursions between even two perfectly flat records where everything else was constant. How else to explain it other than the subsonic frequencies were part of the recording rather than generated by the playback system.
Actusreus (Threads | Answers | This Thread)

I'm not disputing you have woofer movement, nor the fact that the KAB high pass filter removes these subsonic frequencies. The sub-sonic frequencies are generated by the playback process but probably not by music content. It would be asking for trouble to deliberately record music signals at around 10Hz and I doubt this would be done intentionally. Nonetheless I suppose there probably is unintentional low frequency signals recorded. However if most of your records have an *excessive* woofer pumping effect I'd say the problem lies with the arm/cartridge/turntable.

Whenever I have had this woofer pumping issue, the pumping was usually cyclic and continued regardless of music content on the record - more often than not linked directly to (even minor) irregularities in record flatness. I've also observed a contribution by 'bouncy' flooring - where I could see large pumping as I walked up to change the record. I don't get either of these issues with my 103R/Phantom/TNT in my current room.

Some cartridges I've tried in the past, the Shinon Red and Grado TLZ come to mind, have greatly exaggerated low frequency pumping to the point where they weren't practical to use in that particular vinyl system. Other cartridges, the Audio Technica Art 1 and Garrott P77 for example, were very well behaved on the same records/same system, with only minor pumping effects. It's worth noting that both the Shinon and the Grado were somewhat higher compliance than the AT, though theoretically both should have been ok in a medium mass arm (I was using either the Sumiko MDC800 or the SME V back then).

I've seen a huge variation in this effect over the years with different cartridges/tonearms. Some cartridges also behave wildly at resonance (observed with test record) while others have only mild movement. FWIW the lowly Denon 103R is one of the best behaving cartridges I've used in this respect. Whether this is because of its 'lossy' mechanical construction I don't know. I can tell you that even when this cartridge is made much heavier, 14.5 grams in the Al body I use, there is still no issue - even though the resonant frequency has dropped to around 7-8Hz in the Phantom (observed via test record).

By all means get the rumble filter if you must use a particular combo and you have issues you can't solve with damping etc - personally I'd rather avoid the issue (change combo), but that's just me. Either way I hope you can sort out your problem.

Are subsonic frequencies - below 20Hz - cut into records?

According to many high-end audio dealers and several engineers I queried about this issue, the answer is yes. Here is a quote from the KAB website:

One of the biggest let downs with phono playback is subsonic rumble. Actually part of the recording itself, even the best turntable will reproduce it. And with todays cross over video and music entertainment systems, response down to 10 Hz is common.
A good rumble filter will actually improve the bass response by removing those deep subsonic dynamic swings from the system altogether. The power amp breathes easier and the woofers can concentrate on the music at hand.

Getting into LP's and startled at the big speaker cone movements that you're seeing? Thinking a better turntable will help? It may not! This very low frequency energy is called rumble. Much of it is actually cut into the record groove when the master disc was made. Other sources are mis matched tonearms, poorly damped tonearms and acoustic feedback. Often, the only way to suppress rumble is with a really good rumble filter.
With rumble eliminated, the soundstage becomes more "still" and the bass actually tightens up because the woofers are no longer modulating and the power amp is no longer wasting current resources on sub audible noise.

I understand it's marketing as well on KAB's part, but I certainly noticed differences in the degree of woofer excursions between even two perfectly flat records where everything else was constant. How else to explain it other than the subsonic frequencies were part of the recording rather than generated by the playback system.

07-07-12: Actusreus
....if you have very low frequencies cut into the record itself during the cutting process, which is quite common and a fact, your speaker should flutter without a filter unless your system is incapable of reproducing these low frequencies. Certainly a mismatch will make it even worse, but scientifically, how would a full range system suppress subsonic frequencies cut into the groove?

Are subsonic frequencies - below 20Hz - cut into records? AFAIK, there are good reasons cartridge resonance is generally positioned around 10Hz. Firstly to keep it above warp induced low frequencies, footfalls etc and secondly to keep it clear of recorded signals. It would cause serious tracking issues if recorded material coincided with cartridge resonance - witness what happens on a test record which has deliberately been cut with these low frequencies.

Cartridge resonance can't be avoided, it's how the cartridge/tonearm/table deals with this resonance (and other low frequency artifacts) which makes the difference IMO. I agree that having resonance in the ideal range doesn't mean you'll avoid issues. Some woofer movement due to low freq artifacts is perhaps to be expected in a vinyl system, but it needn't be excessive or problematic.

You can use Blu Tack instead of tape as well.

I'm with Srwooten though - I'm very skeptical about claims that people's systems are completely free of rumble. I don't care how well your tonearm/cartridge are matched; if you have very low frequencies cut into the record itself during the cutting process, which is quite common and a fact, your speaker should flutter without a filter unless your system is incapable of reproducing these low frequencies. Certainly a mismatch will make it even worse, but scientifically, how would a full range system suppress subsonic frequencies cut into the groove?

07-06-12: Sbrownnw
@johnny, never had the factory cartridge on my Xpression. Had two mc-3 turbos on it and recently had the ortofon mc 25 fl with the heavier counterweight and it did the same thing (the 25 fl is about 10g). How do I add fluid? Is the tape u mention for my tone arm easily removeable if it does not work out?

Well, it looks like I shot my mouth off without paying closer attention. I realize now that the earlier post about adding damping fluid was contributed by someone else who has a tonearm that uses it. So never mind about that.

Second, one thing that makes this difficult is that what may be a normal amount of pumping for one person may be alarming or excessive to someone else. Third, pumping can come from record warps, how the bass groove was mastered, and tonearm/cart resonance. How bad the speakers pump is relative to the amplitude of the resonance.

If you tape your tonearm, it's reversible. There is no adhesive on the tape; it is very thin and stretchy. However, since you have a carbon fiber tonearm, the effect of an arm wrap is probably minimal. My tonearm is undamped hollow aluminum, so the arm wrap made a significant audible difference. With a more modern carbon fiber arm, probably not so much, but it's only a $1 experiment. We're talking about Teflon pipe thread tape, which should be a buck or two at Walgreen's or Home Depot.

After looking over the entire thread and getting a better feel for your rig, it looks like the KAB RF1 Rumble Filter addresses the various problem sources most directly.

There is rumble recorded in about 50%+ of the records I own, and it has NOTHING to do with set-up or placement or arm/cart matching. When I go to the audio shows I always notice woofer pumping, even on super $$$ set-ups. On a lot of LP's it is unavoidable. KAB's rumble filter is a God-Send and seemingly transparent, at least in my system. When I play LP's, I flip on the KAB.

@johnny, never had the factory cartridge on my Xpression. Had two mc-3 turbos on it and recently had the ortofon mc 25 fl with the heavier counterweight and it did the same thing (the 25 fl is about 10g). How do I add fluid? Is the tape u mention for my tone arm easily removeable if it does not work out?

07-04-12: Tobes
Adding mass to the cartridge/tonearm will lower the resonant frequency. Note that warp induced signals are in the 0.5 - 7Hz region, so you don't want to drop the cartridge resonant frequency too low if your cartridge/arm/table already has a problem in this area.

FWIW, I can't recall any cartridges I've used that have fallen outside the broad ideals for cartridge resonance, say 8-14Hz, when a test record is used. However there have been large differences in the amplitude behavior at resonance - no doubt due to the different construction methods of the particular cartridges and arms. ...

Right, but 10-11 Hz is considered more ideal than 13-14 Hz or 5-8 Hz. Adding 4-5 g of effective mass to the OP's rig will lower the resonant frequency from 13-14 Hz to a more ideal 10. However, as you mention, there's the resonant frequency and then there's the amplitude of that frequency. The OP noticed the increased pumping after changing from the stock cartridge on the Xpression (Sumiko Pearl) to the Ortofon, so it seems that there's something in the cartridge swap that increased the pumping. The Pearl weighs 2g more than the Ortofon and is a little more compliant as well at 15 vs. the Ortofon's 13. I don't know enough about the Turbo's housing to form an opinion on its damping, but when you combine a very light arm (8.7 eff mass) with light cartridge (4.1g) and stiffer compliance, you're raising the resonant frequency, and with the lower mass the amplitude would be higher too.

Fortunately the OP's tonearm has a fluid damper, so he may be able to add fluid to lower the amplitude of the resonance. Increasing the effective mass with headshell weights should not only lower both the resonant frequency and amplitude as well.Wrapping the tonearm in PFTE pipe thread tape might help a bit too, both in damping and effective mass. It sure made my Technics tonearm sound better and more linear.

Adding mass to the cartridge/tonearm will lower the resonant frequency. Note that warp induced signals are in the 0.5 - 7Hz region, so you don't want to drop the cartridge resonant frequency too low if your cartridge/arm/table already has a problem in this area.

FWIW, I can't recall any cartridges I've used that have fallen outside the broad ideals for cartridge resonance, say 8-14Hz, when a test record is used. However there have been large differences in the amplitude behavior at resonance - no doubt due to the different construction methods of the particular cartridges and arms. For instance I'd expect a rigidly constructed Lyra cartridge to produce a higher Q resonance that a cartridge built on a plastic frame/body. The latter type of cartridge will probably be easier to accommodate, though of course that doesn't make it better.

@johnny, I will have my shop try adding 4 grams of weight with heavier hardware, etc. I do have the Clearaudio Clever Clamp. I hope it works! Thanks.

Actusreus, you're finally on the right track with the damping fluid. As some have mentioned before, your problem is not an issue of wow, flutter, or rumble. Rumble comes from noise from the motor (usually an old style idler drive turntable) getting picked up by the cartridge. Your problem is most likely a mismatch in cartridge compliance and effective mass of the tonearm, which causes the woofers to visually "pump" at a very low (e.g., 10-13 Hz). Damping fluid can lower the amplitude of the resonant peak. Increasing your tonearm's effective mass can lower the frequency to where it has less audible effect and improves cartridge tracking.

Here is the cartridge/arm compatibility for the Ortofon MC-3 Turbo. Its compliance is 13 and cartridge weighs a very light 4.1 g. The Pro-Ject Xpression tonearm has a low effective mass of 8.7 g. This puts the resonant peak at 12 Hz and close to 13, which is outside the ideal of 10 Hz. If you could add 3-5 g to your arm's effective mass (which you could do with a headshell weight), this would push the resonant frequency down to the 10-11 Hz range which is near ideal. According to the Xpression's specifications, the stock tonearm counterweight can accommodate cartridges weighing from 7-12 g and there's an optional counterweight for lighter cartridges of 4-7 g. As you can see, you have one of the lightest cartridges on the market. Did you switch to the other counterbalance to accommodate it?

Since you're better off sticking with the original counterweight and increasing your tonearm's effective mass to lower the resonant frequency, get a headshell weight, heavy mounting hardware, or both to increase the tonearm effective mass by 3-5 g to compensate for the low weight of the cartridge. This will increase the effective mass to overcome the relatively stiff compliance of your new cartridge. If you do this and top off your damping fluid, the woofer "pumping" should diminish significantly.

You may also want to consider an aftermarket turntable mat to help dampen resonances and further isolate the turntable's mechanical noise from the cartridge. A record grip or clamp may help a bit too; it certainly does on my rig. It doesn't have to be expensive--the acrylic one from Clearaudio or the rubber one from KABUSA.com (both around $30-35) should do fine.

I suspected the tonearm might be at least partly to blame. I did apply a little bit of the damping fluid a while ago, but will experiment again. Thanks Tobes.

Actusreus, I don't have any personal experience with Lyra cartridges. I did notice in looking at the specs of the Delos that the compliance is quoted as "12 x 10-6cm/dyne at 100Hz", indicating that the compliance would be considerably higher at the cartridge resonant frequency - but this in itself shouldn't push the resonant frequency too low with a typical medium mass arm. It's actually difficult to get a really bad match. Even the highish compliance (for an MC) AT PTG-II posed no issues for me in the medium+ mass Phantom - though, anecdotally, any issues I've had in the past with other arms were with higher compliance cartridges.

I have read that Lyra cartridges are demanding and put a lot of energy back into arms. What you are getting may be the combination of the Delos' slightly higher compliance (= lower resonant freq), strong transmission of energy and the perhaps the VPI arm is not ideally coping with this. Have you played with the oil damping on the VPI?

Assessing the resonant behavior with a test record can help you see what you're dealing with. I've found there can be a marked difference between what the specs suggest and practical results.

Tobes,
What would you suggest in situations where the tonearm/cartridge match looks perfect on paper, but the woofer pumping continues? I have a VPI Classic with a Lyra Delos and I still experience excessive woofer movement. The Classic stands on a 4-inch thick maple block, which in turn rests on Isoblocks. The rack stands on four heavy concrete squares and there are a few more in the rack to add mass. Granted, the turntable is between the speakers, and only a few feet away from one of them, but this is the limitation I have in the placement and it cannot be altered.

I'm just curious what your advice would be in situations where there is no apparent mismatch between the arm and the cart, you can't experiment with placement and you've done nearly everything possible to address resonance short of moving to a different apartment or spending $$$ on a state-of-the-art rack or replacing the analog front.

Twice your normal listening level? Turn the goddamn thing down. It's an inexpensive table and it can only take so much.

There is a mixing of terms here.
Wow actually refers to longer term speed variations in the turntable. Flutter is short term speed variations. Neither has anything to do with what you're experiencing.
Rumble used to be the term used to describe noise contributed by the mechanics of the turntable - bearing/ motor noise etc.

Excessive woofer movement is often caused by low frequency feedback to the turntable (acoustically generated or footfalls etc) or warp induced low frequency signals being picked up by the cartridge. Since you have a wall shelf I suspect the latter.

Often these signals will be accentuated by a mismatched cartridge resonant frequency - ie if cartridge resonance occurs too low (below say 7Hz) this can emphasize these low frequency problems.
A heavier cartridge will lower the resonant frequency. A higher cartridge compliance (all else equal) will also reduce the resonant frequency.
Some cartridges just seem to be more susceptible to this issue, perhaps due to poor damping?
Not that it helps you, but I simply haven't had this issue at all for the last 20 odd years I've been using Graham unipivots.

It would be preferable to find the source of the issue rather than apply a bandaid like a low frequency filter. Not only does the latter add another device into the signal path but not dealing with a resonance problem may have other tracking and sonic compromises.

Ahh, the rumble. I told my dealer I had a rumble problem and he looked at me suspiciously. It did sound rather strange...

What I don't quite understand is why you would crank up the volume twice as high as your normal listening level and then notice the problem (unless I misinterpreted your post, but it seems to plainly state just that). I think a more important question is: do you have that same problem at the normal listening level? Even without rumble, if you crank up any system to twice the normal level, there will be a significant woofer excursion. There has to be to generate a much higher SPL.

Its either acoustic feedback or tonearm/cartridge compatability. I doubt its a compatability issue because your TT/arm/cartiridge are all very common and medium mass. I stil say its acoustic feedback...

Forgot to mention it is on a wall shelf with long lag bolts into the studs. It is on its factory isolation cone feet.

It doesnt sound like your TT is malfuctioning. Rumble is generally caused by acoustic feedback, particularly in TTs without suspension. Try isolating the TT on a wall shelf, pods/cones or some other method.

I have a rumble filter on my Pro-ject phono tube box Ii but it does not remove it all plus it sounds like the table is not operating up to spec.

But does this sound normal for Pro-ject or other turntables or should I be looking at getting this table repaired under warranty or maybe replaced?

If you need a filter, try one from KAB. You wont get any rumble after its installed.

Be carefull coz you can blow your speakers. Normally if the record is perfect with no clicks, pops, you don't need rumbe filter. Also turntable should not be too close to speakers. I recommend to listen to analogue at reasonable volume levels before it starts to rumble.