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Speaker cone movement on vinyl

YNWOAN said:
Sorry, I wasn't paying attention and thought it said Mana stand. The wall shelf will make a difference. Sorry for the confusion.
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Just following the thread and was a little bamboozled :confused: until I read your last post. Pew! :D

Now to think how I will fit the darn thing.
 
Movement in the floor, and warping of the vinyl is exciting the fundamental resonance of the arm/cartridge. This sends subsonic signals into the system causing cone flap.

Others have given advice about wall mounting the TT and I would agree with that, plus I'm strongly in favour of sensible LF filtering in the phono stage.

The problem is however exacerbated by a poor mass and compliance match, especially if the arm lacks any damping so you might well improve things with a different choice of cartridge or arm.

Don't underestimate the problems this causes.
In a 2 way reflex loudspeaker the critical mid range frequencies are being radiated largely via the woofer cone. If this is jumping around a given point in space the effect is to add unpleasant distortion. In addition the woofer voice coil is being pushed away from its most linear operating region, and the amplifier is being asked to deliver additional current for no sonic gain.
 
Or get sealed / acoustic suspension loudspeakers. They don't unload the woofer below resonance like reflex designs do.
 
A wall shelf will help, especially with footfall but cone flap is mostly caused by the cartridge tracking record warps. These are subsonic and get amplified. Most LPs are warped to a greater or lesser extent. A phono stage with a subsonic filter is probably the most effective solution.

Rich
 
What Rich says. You can buy a subsonic filter for not much and it's well worthwhile in many cases.
 
Or get sealed / acoustic suspension loudspeakers. They don't unload the woofer below resonance like reflex designs do.
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As the owner of several sealed enclosure type speakers (Yamaha NS1000’s and LINN KAN’s) I can tell you that a sealed enclosure speaker can still be sensitive to excessive cone movement from sub-sonic breakthrough.

The excessive cone movement is caused by a mismatch between the pickup arm’s effective mass and the cartridges compliance. It can be circumvented by the use of a subsonic warp filter within the Phono-stage as very few LP’s are cut with information below 40Hz or so as this gives the cutter head a really hard time, most mastering engineers deal with it by removing it entirely.

However, don’t forget that the excessive cone movement is essentially caused by excessive stylus / cantilever movement at the cartridge. As I said before, this is caused by a mismatch between the pickup arm’s effective mass and the cartridges compliance. A sub-sonic warp filter only hides the problem.

To properly cure the issue you will need to change the cartridge and go for a cartridge that has a little less compliance. Most of the SURE cartridge designs come from a period when ultra light weight arms (and all their associated problems) were more common.

LPSpinner.
 
No disagreement about curing the problem at source. All I was pointing out is that reflex loudspeakers have only the suspension spider to control excursion below (port) resonance, whereas the sealed box has a progressively stiffening air spring in addition to the mechanical spring/spider to limit excursion.
 
James said:
No disagreement about curing the problem at source. All I was pointing out is that reflex loudspeakers have only the suspension spider to control excursion below (port) resonance, whereas the sealed box has a progressively stiffening air spring in addition to the mechanical spring/spider to limit excursion.
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Hi James:

This is true to a point, but it is my experience that below the speakers system resonance (where the sub-sonic noise is active) the compliance of the air trapped in the sealed enclosure does little control excessive cone movement in a sealed enclosure, although I will agree that it probably behaves better than what would happen in a ported or open baffle design.

LPSpinner
 
If the OP likes the 'Shure sound' it might worth while trying an M97xe which is a bit more stiffly sprung and has the 'damping brush' which may help to lessen the cone flap and best of all is generally available for not too much dosh.
 
This is normal for a phono stage with the old 1953 RIAA curve. The update, in 1976 included a sub-sonic roll-off to avoid this sort of thing.
IMO it is all bad. It is your arm/cartridge being excited by structure borne vibration as you walk about. All output below about 2x the arm cartridge resonance is either spurious or inaccurate anyway so a phono stage with a 1976 RIAA curve or a high pass filter will fix it.
Putting the TT on a wall shelf or proper isolation will reduce the excitation, and is a good thing to do anyway, but will not fix the fundamental problem, which is that the non-accurate part of the cartridge output is being excessively amplified.


Edit: Certainly having a compliant cartridge in a heavy arm can move the arm/cartridge resonance down to a region where it may be excited by warps. Having a low compliance cartridge in a low mass arm will move the natural frequency up to a level where it may start to be excessively excited by actual music (though this is not cone flap) ruining the phase and amplitude accuracy of the bass.
A good match between cartridge and arm is very important, but it will not prevent cone flap whereas a high pass filter will.
 
All interesting stuff - thanks.

I've had an AT-OC3 kicking around that came on a turntable (so unknown origin / wear) but tried that this evening out of interest.
The effect is still there but it seems less pronounced. It's a physically heavier cart than the shure (quite a bit!) and tracks a little heavier. Also it's MC instead of MM if that makes any difference to 'cone flap'!?
 
There's nothing fundamental between MC and MM. The higher mass and lower compliance has shifted the resonance frequency
 
The AT is too heavy for the arm though (or at least the counterweight) as the adjuster is nearly screwed out the end leaving the weight flapping about and dodgy azimuth adjustment.

I've also got a couple of Shure M75EDs and a Goldring Elan but they should (in theory) sound worse than the M91ED (although in the case of the M75, probably not much) unless the effects above are particularly pronounced with the M91 on my arm which, according to the above posts, will be doing SQ no favours.

I've got a Rega RB300 arm I could try but the previous owner pulled the external wiring off so I need to sort that and find an SME mounting adaptor for it before I can try that.
 
Just as a footnote to this - experimented with some sealed speakers and it didn't make much difference.
An old pioneer turntable instead (with a Shure m75ed) and the effect was much reduced in the same position.
 
All turntables output subsonic grodge ™ it is not a fault, it is inherent in the way they work. You can change the frequency by changing arm or cartridge. You can change the amplitude by applying damping and changing the support arrangements but you can not change the basic engineering fact that that is the way the transducer works.
The only way to prevent it is to only play perfectly flat concentric LPs on a record deck mounted so footfall and other environmental disturbances do not effect it.
Good luck with that.
Using a phono stage with a high pass filter is the only solution which makes any sense practically, from a laws of physics POV.
This seems to have been forgotten in the recent surge of interest in LPs, along with a lot of other stuff which was well understood 40 years ago Duh!
 
Radfordman said:
What is the old Pioneer turntable? PL-12D / M75ED was a good combination, I still have one.
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This one was actually a PL-112D but until recently I also had a PL-12D with the same cartridge. Both sound a lot better than you'd expect given that they were relatively budget decks in their day.
Having a clear out as we're moving house so now sold both! Will probably regret it.
 
You could try a Shure M97xe, perhaps with the much better Jico SAS stylus,
and use it with its in-built damper. This pretty much kills the arm/cartridge resonance.

shure_m97xe_lf_response.gif
 
Geoff101 said:
This one was actually a PL-112D but until recently I also had a PL-12D with the same cartridge. Both sound a lot better than you'd expect given that they were relatively budget decks in their day.
Having a clear out as we're moving house so now sold both! Will probably regret it.
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Thanks, as well as the PL-12D, I have a PL-512, I think that is a great deck too.
 
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