Quiz about adding dense mass to a vibration isolation application!

JW:

My electronics are located outside the listening room (in a hall closet located behind the speaker wall in the living room).

I drilled 4 small holes through the double wall to run speaker cable to the living room.

Various footers and shelves placed under my TT/CD decks do alter the sound (same with a DAC when I used a seperate one).

You can experiment with items you probably already have around the home...

For soft footers cut up an old mouse pad.

For hard footers try matching ramekins, shot glasses, bat gammon pucks (you get the idea).

I finally ended leaving the gear stock (footer wise) and placing them on specialty shelves custom made for my rack.

Tried EAR, Mapleshade, Racing Cone, et cetera, footers, but never tried springs. 

DeKay

One thing that makes me happy with this subject is that people are paying attention to measurements! I can't say I've been able to identify a sonic issue related to DAC vibrations myself. Regardless, the process of achieving vibration isolation and measuring the results with accelerometers is interesting to me. It would be fascinating if someone could show DAC output measurements that correlated to the improved vibration isolation. A simple listening test could involve attaching an exciter or bass shaker to a DAC to see just how bad it can be made to sound.  Maybe very specific frequencies are problematic, others completely benign. Maybe some frequencies help! You never know until you try.

Love these threads! 

To couple or decouple, that is the question.

That and mass loading :)

I keep coming back to the same answer. Whatever unwanted vibrations that exist in the component, they need to go away. So, couple the component to something of a significant enough mass and of an appropriate material that will absorb those unwanted vibrations. Then decouple all of that so no external vibrations make their way back into the component.

But, is that even right, and how to do that effectively?

First, I'm a believer now in decoupling everything.  But you are correct about energy having to go somewhere.  Passive components like DACs and preamps have little created vibration energy- the transformers perhaps.  Active components like speakers and CD Transport motors are creating vibrations and that energy needs to go somewhere.  My experience is that the speakers definitely need a way to drain energy and that was measurable.  My speakers perform much better sitting on the spring loaded wood platforms vs directly on springs.  They are decoupled in both cases but the speaker cabinet still rings for over a second when I hit it with a steel ball when sitting directly on springs.   The speaker cabinet has no ringing at all when sitting on the spring loaded wood platforms.  The sound difference is striking.  The clarity and detail is vastly superior with the speakers sitting on the spring loaded wood platforms.

I experimented with my preamp directly on springs, on a spring loaded wood board and spring loaded HDPE board.  In all three of these cases the preamp is well isolated.  No vibrations from the music get through to the chassis vs the preamp sitting directly on the shelf.  Based on listening, I preferred the preamp on the spring loaded HDPE board or the spring loaded wood board the best.  Between the wood and HDPE I probably could not distinguish in a blind test.  

I designed my spring loaded wood platforms for the speakers to have limited travel.   The speakers will rock if pushed on but only a small amount with no risk of tipping over.  They sway at 3 Hz and quickly come to a stop.  The preamps and DAC have little play as well.  I am able to have just one spring per footer (two springs required on the one footer near the transformer) on the preamps and DAC which leaves about 0.200" travel.

I tried putting springs on my entire stereo rack.  It weighs about 450 lbs, I estimate. It took (8) 57 lb/in springs.  It worked but I did not like my entire rack swaying.  That much weight and all of my equipment moving with just a touch was too unnerving.  I'm more comfortable with individual isolation.  This was a good 3 hours work to put the entire rack on springs and then take it back off of the springs.  The things we do for this hobby.

Lol @tonywinga ! That's hilarious. I can picture it all in my head.

@gladmo why do you still find it necessary to put your subs on springs atop the SubDudes? Doesn't the foam between the MDF and the fllor isolate them as is?