Turntables: How Much MASS Is Enough?

[MattHooper]

Some of this has been tossed around the forum in other threads, but feeling a little frivolous...

I don't go in for all the audiophile stuff (in the more subjective forums) about having to mechanically "isolate" CDPs and DACs, that footers make any difference to most audio gear, etc.

But a vinyl playback system work by essentially detecting teeny vibrations and magnifying them hugely to become the sound coming out our speakers.

So the fact good turntable manufacturers go to some lengths to minimize picking up spurious vibration or other forms of spurious noise, makes engineering sense.

But, to what degree and when is enough enough?

I admit that *conceptually,* on a sort of psychological level, the lengths to which some audiophile companies go to minimize any possible vibration getting to or occuring from the turntable are fascinating and move between "that's pretty cool, I'd love to hear that" to ..."well...that looks crazy overboard." You've got vaccum systems that will hold the LP to the platter flat. You've got metal platter/plinth high mass turntables like this:

http://www.unitedhomeproducts.com/17cbe8980.jpg

And this:

https://tricellenterprises.com/wp-content/gallery/munich-show-2018/muni22.jpg

And you guys I'm sure have seen plenty of others like them.

I'm also aware there are "low mass" turntable aficionados as well.

As I've mentioned in other threads, I moved from an old micro seiki turntable (a good one) to a (second hand) Transrotor Fat Bob S turntable:

Clearly it's from the High Mass school of design.

As I've said before, I have no friggin idea if this turntable is actually objectively better than the one it replaced. Doing a side by side back and forth would have been impossible. All I can say is that it sure sounded to me like a decided improvement across the board: cleaner sounding, clearer, the general background noise in records seemed to be obviously reduced, sort of like moving from an old vinyl set up to listening to CDs in a way. Was it due to all the over-board-looking measures this company takes when making a heavy-assed turntable like this? Dunno. I like to imagine so

But whenever the audiophile side of my brain even contemplates a new turntable "upgrade" (never actually going to happen) I look at my turntable and think: "what else could actually be done to make any audible improvement, lowering of spurious noise etc?" I mean, the thing already looks over-built, and yet there are far more complicated, massive turntables built with an obsession to "reduce vibrations." It reminds me of the tweaky side of audiophile systems, speaker cables, ac cables, power conditioners, cable risers, each additional tweak "lowering the noise floor further" as if both the audio system and the audiophile's ears had some sort of infinite dynamic range that could realize such benefits.

So, I guess the point is: I'm skeptical even about my own turntable, that it's already overbuilt and likely well in to the diminishing returns category. But...I don't really know. And some of you have been in to turntables seriously (even if in the past, not now) more than I have, and we've got some great technical knowledge here, so just thought I'd throw that to the crowd.

 

[TheWalkman]

What kind of motor does it take to turn a Fat Bob platter: gas or diesel?

 

[MattHooper]

What kind of motor does it take to turn a Fat Bob platter: gas or diesel?

We have a wind turbine in the back yard to do the job.

 

[Blumlein 88]

I for a long time used a stand that helped with any of the turntables I think. Arcici Lead balloon.

Welded with hollow legs you filled with lead shot or sand. I chose sand. The top platter sat on tip toes type feet and soft lead bars ran across it. You sat the TT on the lead bars. It did reduce much vibration from getting to the table and seemed to absorb some of it though that latter part isn't as clear cut, and would depend upon the feet of the TT in use as well as its own suspension.

The other setup that definitely worked was a sturdy wood box, filled with 8 inches of sand, and a floating wood plinth floated upon the sand, but it was spaced with a small gap between the sides of the box. It did better than the Arcici I think. It was an idea I got from amateur table design for those that made holopgraphic images which are terribly sensitive to vibration. A friend later made one using synthetic marble for the box and plinth. Getting it level was a bit of a chore, but surprisingly once level it stayed level.

This device meant for placing an analytical balance upon would work. Too expensive and heavy for TT use ($3500 and 700 lbs). I worked in a lab where the building was full of 500-1000 hp electric motors running blowers. The building including the lab was on one slab and you could feel tingling in your feet if you stood still in the lab. This simple table design of granite however kept any of that from upsetting the mechanical analytical balance we used.

One could also create feet that work like dual or triple friction pendulum supports which protect buildings form earthquakes. There are a few brands of those made for TT. These would be lightest though they only work for horizontal displacement. I think Townshend made some like this. Here is how those for a building work.
https://opensees.berkeley.edu/wiki/index.php/Triple_Friction_Pendulum_Element

 

[Wombat]

The LP record is an airborne-vibration detector.

Clamping it to a tuned-frequency absorber/damper( TT/platter/ mat,}would be beneficial but who give specs to assist in choosing. A base/stand that is similarly designed can be helpful. Some tonearms are better damped against extraneous vibration.

Controlling existing floor or wall(mount} vibrations is last resort. If I lived above a subway or near a trucking route, I'd definitely choose CDs.

P.S. With high-mass TT Platters a rumble filter may be good insurance for your loudspeakers as resonances can be lowww.

 

[MattHooper]

Thanks for the replies. I presume many agree with me that beyond a point there's no more vibration/noise to supress. I'm still not sure what point that would be in terms of turntable design.

I know designers try to make tone arms that won't be affected by, or produce extraneous vibration. But what vibration are we really worrying about? Mechanical-born vibration from the turntable system itself, or air-born (e.g. from the music being played in the same room)?

Wombat: My turntable came with a weight to place on records, which I use. I haven't tried the actual clamp-type yet, though, which screws down to tighten the record to the platter. I've seen some people do a with vs without record claim recording on youtube, and there seems to be some distinct audible differences in some demos.

 

[watchnerd]

My current house has a suspended floor.

My last house had a concrete slab floor.

I think the answer to 'how much mass' depends on your flooring.

In my suspended floor house, I like having a suspended TT better -- it's more resistant to footfalls.

Suspended TT's aren't high mass, so in my case, I've had better results not going with the more mass route.

In my last house, with the concrete slab, it was the opposite; heavier was better.

 

[watchnerd]

But what vibration are we really worrying about? Mechanical-born vibration from the turntable system itself, or air-born (e.g. from the music being played in the same room)?

Everything.

Including cartridge + tonearm resonance in subsonic frequencies, as determined the interaction of your arm/cart effective mass + compliance.

 

[watchnerd]

So, I guess the point is: I'm skeptical even about my own turntable, that it's already overbuilt and likely well in to the diminishing returns category. But...I don't really know.

Have you checked the speed stability?

I lot of getting the most out of a TT is about optimizing what you've got, as opposed to just upgrading the TT.

Your TT is already at the diminishing returns level, unless you go in a completely different direction like linear trackers.

 

[MattHooper]

My current house has a suspended floor.

My last house had a concrete slab floor.

I think the answer to 'how much mass' depends on your flooring.

In my suspended floor house, I like having a suspended TT better -- it's more resistant to footfalls.

Suspended TT's aren't high mass, so in my case, I've had better results not going with the more mass route.

In my last house, with the concrete slab, it was the opposite; heavier was better.

Yes, I've certainly seen the difference between suspended wood flooring and concrete slab!

My turntable room, 2nd floor, is on suspended wood flooring. Without any intervention, a turntable skips like a bugger if my Godzilla of a son is walking anywhere nearby. And with a hand on the top of the equipment shelf I can feel tons of vibration just from normal footsteps in that room. That's why I went to town designing an isolation platform, constrained layer damping, springs etc. With a hand on top of the isolation platform no footstep vibration can be felt, and it barely registers using a vibration-sensing app on the iphone/ipad (vs huge resonating spikes showing without the isolation platform).

Then I go over to my pal's place where his hi-fi/turntable is set up in his basement - concrete slab. Placing a hand on his equipment shelf, no stomping/footstep vibration can be felt. And the vibration app registers virtually nothing! Damn, that was impressive, just from a change of floor material.

 

[MattHooper]

Speaking of mass/resonance, here's an interesting youtube comparison with a record clamp on and off. Seems to make a distinctly audible difference (I was going to mention what difference I hear, but won't prejudice others before listening).

 

[watchnerd]

Speaking of mass/resonance, here's an interesting youtube comparison with a record clamp on and off. Seems to make a distinctly audible difference (I was going to mention what difference I hear, but won't prejudice others before listening).

My original clamp was like that.

My new one is a spindle-screw-on kind.

 

[Blumlein 88]

Thanks for the replies. I presume many agree with me that beyond a point there's no more vibration/noise to supress. I'm still not sure what point that would be in terms of turntable design.

I know designers try to make tone arms that won't be affected by, or produce extraneous vibration. But what vibration are we really worrying about? Mechanical-born vibration from the turntable system itself, or air-born (e.g. from the music being played in the same room)?

Wombat: My turntable came with a weight to place on records, which I use. I haven't tried the actual clamp-type yet, though, which screws down to tighten the record to the platter. I've seen some people do a with vs without record claim recording on youtube, and there seems to be some distinct audible differences in some demos.

I think there is a priority with vibration from the table itself being #1. Also if you have a poor design there is a limited amount you can do about it.

Next is mechanical vibrations from the cabinet or base you have it upon.

Least is airborne vibration which still can be enough to matter. Just put your needle on a record sitting still. Play some CDs and record the phono pre output. You'll hear some of the music in the room. You'll hear lots if you have a plastic TT cover.

The base you can decouple above a certain low frequency of a few hertz. Those Seismic isolators from Townshend work like that. They are basically a spring wrapped in compliant rubber for damping. You adjust stiffness of the spring relative to weight of the TT and get a filter that blocks vibration from being transmitted if it is above 3 hz. I think they are basically a 2nd order mechanical filter. The cup and ball type feet basically only work for horizontal vibration. And work on a dual focus pendulum idea.

 

[watchnerd]

They are basically a spring wrapped in compliant rubber for damping.

I just have actual springs on mine.