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Comment by rdiddly | Hacker News Reader

They, and each of the reviews they quote, carefully avoid any mention of any auditory benefits. Are there none? To me, the real reasons for doing this would be

1) to isolate the turntable from floor vibrations. Walking or stomping nearby, or even closing a door, can be picked up and amplified as a rather unpleasant booming low-frequency sound. And jumping hard enough nearby can even make the needle skip.

and possibly

2) to eliminate the mechanical motors and thereby another source of noise or interference. All while possibly achieving better or more consistent control of rotation speed?

So, why are any such claims so scrupulously avoided? Because it doesn't accomplish either of those things? Because their experience with phonographs is so shallow they don't even know those issues people might care about? It's weird...

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I don't have data to back this up, but I suspect the main issue with needle skip is from vibrations being transmitted through (and maybe amplified along?) the arm. Since the arm is still mounted to the base, it could be that levitating the platter does zilch for vibrations. I wonder what it would take to levitate the arm too, and just have a flexible cord hanging down to pass along the signal?

Eliminating needle skip was the first thing that came to my mind too, there's gotta be a reason they don't even mention it.

I'll preface this by saying any attention paid to the performance of record players is an absolute waste of effort, in my opinion.... buuuut.

I think that there's a different problem for each component. The turntable introduces vibrations vertically (which seems less important to me, except it could affect stereo), and the arm introduces them horizontally.

It seems to me like the turntable is still connected to vibrations, just magnetically rather than mechanically.

Yes I was wondering about that. Magnetic force follows a power law, so you would think the upward force, once it's at the point of balancing the weight of the turntable, might be almost as rigid as a solid connection. Although it would be less so, the lighter the turntable was, for a given magnetic field strength. But then you would probably incur a "jumpiness/bounciness" penalty. Rather an interesting design problem actually.

Yes, and also turbulence from the wind.

Well, it's a mass and a nonlinear spring connection. The result should be a lowpass filter.

It could be better because it seems hard to make low-pass solids at audio range and beyond: for example, while you can easily make a spring which has low pass behavior in the few Hz range, the spring itself is made of metal and conducts sound normally. I guess you have felt pads and foam (which have thin strands and large number of interfaces for sound to reflect). The magnetic force however should retain its springy behavior up to arbitrarily high frequencies.

They could increase the mass of the platter so that inertia helps with isolation. They say it's 2.2kg and to me that "feels" heavy, but my experience is only with retail-grade turntables and I don't know where that fits in with high-end gear.

An SL-1200 weighs in at about 30 lbs (13.5kg).

Not sure what the weight of the platter itself is off the top of my head.

1.48kg platter on a sl-1210mk2

It's just another way of doing the "bearing". Normally, that's a bit of machining with extremely tight tolerances and a single point of very high pressure contact, either ball-on-ball or cone-on-cone. I had a table about thirty years or so back now - a Revolver - that took a full three days for the platter/spindle to bottom out in the bearing when it was installed. (And while it was "hi-fi", it wasn't nearly high-end. An audiophile would have called it "entry level".)

> to isolate the turntable from floor vibrations. Walking or stomping nearby, or even closing a door, can be picked up and amplified as a rather unpleasant booming low-frequency sound.

The so called "rumble filter" was a common feature of amplifiers from the 80s. Vinyl may have been reborn, but the surrounding ecosystem has not, so most "modern" record player systems are quite inferior to those of the past. Ironic.

It looks cool. The very first sentence on the page is "MAG-LEV Audio's ML1 Turntable visually enhances the experience of listening to vinyl records by levitating the platter."

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