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Speaker cone movement on vinyl

G

Geoff101

Not so new member
Morning,

I noticed something last night and wanted to ask if it was normal.

Whilst listening to a record, I happened to have the grilles off my speakers. I noticed that if I go anywhere near my turntable whilst it's playing and in particular touch the rack, I get a large movement on the speaker cone (as if it's getting DC on the coil). It didn't really look healthy and as I'd never be able to afford to repair them, I'm worried about damaging my speakers.
It never sounded as if the cones bottomed out which I believe mine are prone to but none the less was a bit worrying.

That part of my system is:
Michell Focus One with Hadcock arm and Shure M91ED cartridge
Nakamichi CA-5Eii Preamp using internal phono stage.
Audiolab 8000P
Dynaudio Audience 52SE

I can swap back to my AV32R and external Creek OBH8-SE to see if I get the same on that or is it just likely to be arm setup or something else?
 
Completely normal with a phono stage that does not roll of the LF, or have a 'rumble filter', and particularly with a wobbly tonearm like the Hadcock. You could try a wall mounted shelf for the record player if it bothers you.
 
I don't suppose that the pre-amp has a low frequency or rumble filter as they used to be called? I guess if it did you would have tried it.
 
Yeah its normal but you can do a few things to improve feedback into the turntable which causes the cone flap
if you have a subsonic filter on your phono stage that helps with cone flap.
Also what do you have your turntable sat on ?. A wall shelf is the best thing I have used.
A support that sits on a springy wooden floor will be the worst for feedback and footfall on the turntable
My son has his 1210 in a vibrant sideboard and the feedback and cone flap is terrible

Alan
 
Geoff101 said:
Morning,

I noticed something last night and wanted to ask if it was normal.

Whilst listening to a record, I happened to have the grilles off my speakers. I noticed that if I go anywhere near my turntable whilst it's playing and in particular touch the rack, I get a large movement on the speaker cone (as if it's getting DC on the coil). It didn't really look healthy and as I'd never be able to afford to repair them, I'm worried about damaging my speakers.
It never sounded as if the cones bottomed out which I believe mine are prone to but none the less was a bit worrying.

That part of my system is:
Michell Focus One with Hadcock arm and Shure M91ED cartridge
Nakamichi CA-5Eii Preamp using internal phono stage.
Audiolab 8000P
Dynaudio Audience 52SE

I can swap back to my AV32R and external Creek OBH8-SE to see if I get the same on that or is it just likely to be arm setup or something else?
Click to expand...

Sounds like the stylus is picking up very low frequencies from your footsteps vibrating the floor? Mine will do that if I tap the turntable Some records have subsonic frequencies which wobble the cones in a similarly worrying fashion. I wouldn't worry about it.
 
337alant said:
Yeah its normal but you can do a few things to improve feedback into the turntable which causes the cone flap
if you have a subsonic filter on your phono stage that helps with cone flap.
Also what do you have your turntable sat on ?. A wall shelf is the best thing I have used.
A support that sits on a springy wooden floor will be the worst for feedback and footfall on the turntable
My son has his 1210 in a vibrant sideboard and the feedback and cone flap is terrible

Alan
Click to expand...

Ah yes, subsonic is the term that was evading me, rumble filter comes to mind, it's my age you know. I suppose that some old rumble filters may have been at higher frequencies to subsonic filters.

Quad in their some of their amps had a permanent low filter, some say that this did affect bass. My 80's Nad and Proton have subsonic filters, and these do seem to be a very low frequencies.
 
Thanks all. It's not at all audible but does make the cone extend alarmingly!

The turntable is on a stands unique rack which is on spikes, into spike cups on a laminate floor. The laminate has some sort of felt layer underneath so does wobble a bit.

Hopefully be moving soon so may wait until that to sort it out.

Would a different arm help? When I got the TT, concensus over on wigwam was that they are a decent sounding arm and whilst that seems to be true, I certainly prefer the look and feel of something a little more solid.
Just missed an SME 3009 on AoS for a good price.
 
I'd try and get it onto a wall shelf if at all possible. Laminate flooring is not a good place for a record deck, especially atop a heavy rack. The Focus is a nice deck but offers little in the way of isolation so you should hear a substantial improvement by placing it somewhere immune from floor vibrations. The Hadcock is a PITA to set up but a decent arm once done. It's not the weak-link / to blame here.
 
Geoff101 said:
Thanks all. It's not at all audible but does make the cone extend alarmingly!

The turntable is on a stands unique rack which is on spikes, into spike cups on a laminate floor. The laminate has some sort of felt layer underneath so does wobble a bit.

Hopefully be moving soon so may wait until that to sort it out.

Would a different arm help? When I got the TT, concensus over on wigwam was that they are a decent sounding arm and whilst that seems to be true, I certainly prefer the look and feel of something a little more solid.
Just missed an SME 3009 on AoS for a good price.
Click to expand...

As 337alant mentioned, a wall shelf for the TT is the cheapest solution. Or mount your entire rack on the wall just off the floor? I wouldn't imagine an arm would make much difference but I suppose some cartridges or phono stages may have less low frequency response - the frequency making the cone flap will likely be 20hz and below. I would have thought some phono stages might even put a high pass filter in to prevent this kind of thing? I had an old gold marantz amp that had a 'lo cut' button on it, but 'higher end' amps seem to dispense with useful things like this :)
 
Some of the wobble is the cartridge tracking the vinyl "imperfections" and ripple etc. It does eat into the headroom of your amp and speakers. I have far less of it as I've improved my front end.
 
Assuming your Nakamichi amp has a tape monitoring facililty, which I think it does, then a KAB RF-1 rumble filter would be a possible solution if all else fails. Connects via tape in/outputs of your amp, you'd select 'Phono' on the record selector of your pre but listen via 'Tape'. Not horrendously expensive, either. If you are local to me (Suffolk/Norfolk border) then you'd be welcome to try mine to see if it cures your cone flap.
 
Not local but the offer is appreciated. I think I'll source a wall shelf for the turntable once we've moved and go from there. At least it's a 'normal' phenomenon and not something faulty. Just need to be careful until then.

Thanks again for all the advice.
 
Make sure the bearing is lubricated and in good condition on the TT

You could also look at arm settings, silicone dampening?. Extra weight on the headshell will alter the arms resonance frequency.

Isolation with a wall shelf would be best option, but alternate shelf material may help too.
 
A more general point. Most turntables have poor, to nil, isolation. A few bits of rubber or a block of stone aren't an answer....good engineering and design is.
We, the audio people, are to blame because we have let designers get away with lazy, second rate designs. You can pay thousands of pounds for a 'design' which offers an mdf board with plastic feet. Or £10,000 for a deck featuring a metal chassis and some pointy feet. Hoe can that isolate anything?
Anyway, a wall shelf is the cheapest solution and usually works pretty well.if you can borrow some, Townsend sprung pods can be superb, but will cost more. And, in the meantime, a rumble filter.....
Nice deck, the Michell.
 
It's possible that a change of cartridge may help, if you have one, may be worth trying, perhaps only as a temporary fix.
 
I too have noticed this, particularly with my B&W cone speakers. Regrettably my house has wood floors with around 3 foot of dead space underneath :(

I have however just invested in a mana wall shelf to isolate LP12 from the floor. Hoping this improves matters.
 
oxela23 said:
I too have noticed this, particularly with my B&W cone speakers. Regrettably my house has wood floors with around 3 foot of dead space underneath :(

I have however just invested in a mana wall shelf to isolate LP12 from the floor. Hoping this improves matters.
Click to expand...

YNWOAN said:
I doubt it will make any difference I'm afraid.
Click to expand...

It did in my case going from a floor stand on a suspended floor to a wall shelf. I could jump on the floor near the LP12 when I moved it to a wall shelf. The only problem was when doors where closed in the house, the record would skip. Problems were solved when the LP12 was moved to the basement. :)
 
A bit of an aside, just noticed your cartridge M91ED, I have one of these and it is good, but I also have a M95HE with a good original stylus, find it slightly better than the M91ED.
 
John said:
It did in my case going from a floor stand on a suspended floor to a wall shelf. I could jump on the floor near the LP12 when I moved it to a wall shelf. The only problem was when doors where closed in the house, the record would skip. Problems were solved when the LP12 was moved to the basement. :)
Click to expand...


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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