At what vol level do you get rumble / flutter?

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
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.

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.

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.

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...