In praise of isolation.

Isolation as in components, not personal.

(although, that’s not necessarily bad either)

There has been much praise, and discussion on the forum with regards to spring isolation.

Well, all this praise, caused me to look into how to approach this for myself.

I like to try things before I pass judgment on an idea.

The whole coupling/decoupling thing has been of interest to me for a while.

I get the desire to couple (yeah, I know,,,) as it plants the gear firmly in the ground, and if the base is heavy enough and made of a material that absorbs vibrations, you should be golden.

Then there is the problem of 7.83hz. Nope, not audible, but that doesn’t matter. Anyone who has used a test record to check for tonearm resonance can see quite clearly how an 8hz frequency can make the tonearm shake like a belly dancers belly.

So, decoupling. Springs made logical sense. Except, there was the problem of vintage turntables with their springy/bouncy top plates/platters. That just didn’t seem right.

I made an isolation platform and put springs underneath it. Figured out the proper spring rate and ordered 4 springs to support the 90lbs sitting above them. 
It’s crazy the clear and obvious difference it made. For the nominal price of $100 for the 4 industrial springs, the sonic improvements were off the charts! When coupling, and making changes to the materials used under the TT, and the types of feet used, there was a difference with the clarity of the highs, their brightness and with the bottom end being muddy or lacking depth.

With the springs however, the whole presentation opened up. Everything sounded better, clearer and more defined. Faster, less shrill and I could go on.

Not only am I divorced, but I’m a firm believer in decoupling.

(see what I did there?)

Damned 7.83hz…
Kinda doing something similar. The plinth is just shy of 60lbs. It sits on roller blocks which allows for lateral movement. They sit on a 30lb platform made of MDF and sand filled. The plinth is coupled via the rollers to the platform. The whole rig rests on springs which are in desperate need of damping. That is for the next round of DIY.
I suppose I'm a contrarian 

Let's take a power trsnsformer

If you bolt it hard to the chassis it will sound bad.

Overly tight sound and all the parts on the chassis will vibrate

The transformer will sound better loosely coupled to the chassis so it is permitted to vibrate and does not try to vibrate the entire chassis.

But then not securely mounted.

I use compression springs so it it is loosely coupled to the chassis so it can freely vibrate 
But the wide bottom of the springs sits on a wood block.  This acts as a sink to minimize the vibration transmitter to the chassis 

Pure isolation like an sir bearing platter duo.ds bad

Micro vibrations of stylus and record bounce around the platter with no where to go

Better if bearing anchored in a large plinth to absorb bad  vibrations

If the Plinth is heavy enough and absorbs bad vibrations then you could isolate the plinth on a floating stand 
This you need isolation and path for vibrations to travel and be absorbed 
This has been determined by listening alone 

The critical mass systems footers will free your system in ways you cannot imagine...
Microphonics affect everything. I heard a comparison of 2 powers amps where the only difference was the material of the bottom and the end of the amp with the connections. It was as big a difference as if the amps came from two completely different companies. For what it's worth the material was a VERY expensive plastic replacing sheet metal and the 'plastic' amplifier was much cleaner and better defined.

It isn't just transducers like speakers and turntables that vibration control can have profound affects.

With such a low mass load e.g. a turntable and such limited movement in micrometres, the springs will not act as springs but more like a solid piece of metal.