Tonearm mount to the plinth vs arm board vs rotating arm board vs isolated tower

Dear friends: """  use isomerics or the like between them and the plinth that **will** result in coloration. If carefully hard-coupled to the plinth the coloration is reduced. But using an arm pod is problematic as its likely that it will not be perfectly rigid and dead as the application requires. """

@atmasphere  is rigth with his statement that in theory is true but things are that several professional TT designers/manufacturers choosed the arm pod alternative as Kuzma between many others.

Could be almost imposible for any of us detect those " colorations " atmasphere speaks because we need that the same TT can " accept " to run the tonearm/cartridge with an external arm pod/tower and at the same time that that same tonearm/cartridge can be mounted in the TT with integrated arm board to its plyth. Measure it can be easy but really hear those colorations differences is another way matters.

Way before Halcro or other Agoner goes to the TT nude type of set up I did it with my Denon TTs and latter on with the Technics. With the Denon the set up were really nude no plinth at all and obviously external arm pod and quality level performance differences against a plinthed same TTs was really high and easy to detect it.

It's not true that in a DD TT using any kind of anti-vibration mechanism/palttforms the self generated resonances of that TT does not exist: always are there but we have a very high resolution room/system and the level knowledge to know what to look for through a evaluation whole process.

Later on on those DD TT's I decided to mount it nude seated through tip toes in a 50+ kg of 3 separated/different ( for each TT. ) lovely stones marble, onyx and granite and @dover  is rigth : granite " ring like a bell " and I know because my first stones plinths were not 50+kg but around 20kg and that's why I decided to go way higher.

Yes @dover  like you I prefer to listen that audio signal lower than 100hz.

Obviously that the best option for the OP is to go with the orthodox way mounting the tonearms through the plynth but at the end and as I said we can't be totally sure that in the external arm towers we can detect the added signal colorations. So his question is really open and up to him.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

I heartily recommend that everyone make their own recordings in high fidelity. A nice tape machine and a good set of microphones are required. Find a nice-sounding venue and make a recording of something that you can stand to listen to over and over. Then have it mastered and pressed onto LP. A test is fine- you don't have to make a full run.

At least then you have a reference; you were there, you have the master tapes, you know what it sounds like.

Or you could use a mirror mounted on the item under test, a laser and a sound source to demonstrate how a separate arm pod will not vibrate the same as the plinth onto which the platter is mounted, even if both use the same construction techniques!


In the case of the first you have a subjective means to winnowing out how a separate arm pod is a failed concept; in the latter you have a means of measuring it.


I do agree with Halcro on one thing:

What I DIDN'T appreciate at the time....was that the same principle of weight/mass applies to the TURNTABLE PLINTH 🥴

A plinth that has low mass can't also be rigid and dead (IOW damped with no ringing). In this it appears that Halcro has realized that some of what I've said is true- so my challenge to him is to go ahead and finish the job- build a plinth that has the weight and mass, that is 'dead' and provides a means of mounting the arm **directly** to it. So far what I've seen of his efforts appear artistically wonderful, but lack a bit of science. If you're going to go through all that work, why not try both principles? Of course the same construction techniques should be used so as to minimize variables, otherwise its apples and oranges!

The arguments just go round and round like a record.
Most of us manage to get good sound and most of us have no idea why.
Most of us think we have things figured out as to why our systems sound good to the point we will pick up our figurative sword and vehemently argue our point on boards like this and yet what we won’t admit is that we are always looking for the change that will make everything better.
I don’t claim to be an exception. I fit all of the above.
That said, I think that a cast iron or similar inert plinth weighing 200 lbs or more will NOT make a motor unit-bearing-platter-tonearm interface sound better. If someone gets good sound with such an inert massive plinth it is by fluke, not design. I am thinking of Oswald Mills cast iron plinth for the SP10 as I write this. It might very well sound great with that particular direct drive deck but I doubt the same would hold true for most other designs, particularly idlers.
I like to give this example-John Atkinson can measure loudspeaker enclosure resonance and predict the impact of same on the speaker’s sound quality til the cows come home and Mike Fremer can tap on the plinth while a record is playing and tell us what he thinks this means until the swallows return to San Capistrano but neither test means squat. And further, a totally inert loudspeaker enclosure built like a sarcophagus of poured concrete will likely sound.....dead. Aluminum rings and yet people listen to Magicos and swear to themselves that with all that expensive space age technology and expense and machining, well they gotta sound good. I don’t think they do but if you do, I would suggest it is despite the space age aluminum enclosure, not because of it.
Vibrations have to be tuned and managed, not eliminated. Just as a microphone transducer vibrates, just as a loudspeaker driver vibrates, just as soundwaves emanate from vibrations, so too does a stylus/cantilever. No one argues that those vital vibrations need to be deadened, but then many try to deaden everything else.
Fremer gave Rega’s latest top turntable a rave review. He quoted them as stating their design principle was to keep in mind that a turntable, at the end of the day, is a vibration measuring device. And then out of habit he rapped his hairy knuckles against the plinth and noted it was ’lively" Arghhh. When will we ever learn? Harbeth, Volti, DeVore, Audio Note, and many others have this figured out when it comes to loudspeakers. I am not a Rega guy but Rega has if figured out. But on and on it will go, round and round.

I must be doing something right, if both Geoff and Clearthink are angry at me. Clearthink even used his signature triplicate warning system.  (I mustn't "limit, restrict, or discourage...")   Did you think that Geoff is some shrinking violet who needs to be defended lest he walk away in tears?  Here's the thing, Geoff:  Have you considered that we are riding on an enormous ball that is circling the sun at 67,000 mph, while also rotating about its own axis at about 1,000 mph, at the equator?  My point is that the earth is our platform and everything is subject to those seismic vibrations with which you are so obsessed.  Relatively speaking we are all in a sort of spaceship that is subject to the seismic forces.  Therefore, relatively speaking there is no net motion due to seismic forces of a turntable with respect to a tonearm or cartridge or vice-versa.I'm surprised at you for getting so hot so quickly, but perhaps I struck a nerve.

You didn’t strike a nerve, pal, you struck out.