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…
perkri

Showing 3 responses by tonywinga

I’m a believer now.  I just added a picture and a paragraph or two on my system page. I made my own speaker isolation platforms using hardwood butcher blocks and coil springs.  Imaging is more focused and the clarity much improved.  I am blown away by the improvement. Wow. Just wow.  A very big bang for the buck tweak.  
I isolated my amplifiers yesterday in the same fashion as my speakers.  I put the same four springs on butcher blocks as on my speakers.  Since my amps weigh 100 lbs apiece the resonance point shifts up just a couple tenths of a Hz.  The sound itself didn’t change but I started hearing more detail.  It’s both good and bad.  On digital music now the music decays forever.  It is especially noticeable on Chorale music.  Some digital songs that had a black background before now I can hear some noise deep down.  It’s ambient noise but also even quiet cable hum.  The bad is the extra detail distracts from the music at times.  One song had a quiet buzz off to the right.  I thought a tweeter was going.  Turned out to be the recording.  It took me a while to relax again.  
I stuffed foam inside the springs that I am using for dampening on my speakers and amps.  I believe you want the spring/mass system resonance to be between 3-4 Hz.  That seems to be effective at isolating the speakers, amps, etc from the floor. I am using butcher blocks for ease of fabrication and also because I want to use a combination of rubber feet/dampening with coil spring isolation.  
Another trial I made with only limited success were these spring loaded footers offered on the web.  I purchased some nobsound spring loaded footers to try on my CD Transport.  I am not totally satisfied with them.  While they were inexpensive the plastic upper and lower pieces cause the springs to squeak.  I wrapped the springs with teflon tape and that cured the squeaking.  These footers include 7 springs each but it is possible to use as little as one spring each.  I had to use 2 springs each to support my CD transport.  One spring is not strong enough to keep the footers from completely collapsing in my case.  That limits the lowest spring rate possible to use with these footers for a given mass.  In other words, a lower spring rate would require a longer spring to support a given mass.  Using the VibrationAnalysis app on my iPad, I determined that the resonance point of my CD Transport with these footers is about 8 Hz.  I can't make the spring rate any lower in order to lower the resonance point.  Because of that I also see that the isolation performance is not quite as good as what I have achieved on my speakers and amps.