Quiz about adding dense mass to a vibration isolation application!

I wouldn't know myself, but I have heard some knowledgeable members here warn against sandbags and other heavy items like granite on top of speakers and components even though that might seem like a good idea intuitively.

I'd be interested to know the result.

dunno, i think King Spring is on vacation or hopefully banned… wait and he will be along…someday…

Most importantly, what do your ears tell you ?

Enjoy the music

Jim

I have the Nobsound Springs and I feel the springs themselves are a bit stiff. I'm only using three of the springs provided in each puck and can see my gear sway and move with footfalls near the rack. Not sure how much isolation they're actually providing.

@dadork 

Yeah, I'm experimenting with the Nobsound spring devices too, and I agree they should include springs which are a little less stiff.  So far my results have been that they are pretty effective with four of them placed under my two heaviest components, as well as on top of my Auralex subwoofer isolation platform (under the sub).

But under my four other lighter components, the results aren't as good and I'm looking for other solutions.  Hopefully Townshend will ship out my first set of 4 Seismic Pods soon. I may end up combining two Pods with one foam damped Nobsound under two components.

There is natural resonance of the device versus the resonance of the device environment as it floats on a non-rigid mount. Both of those are on a platform that is vibrating, we presume, at different amplitudes based on the SPL and frequencies.

Not unlike running a sine and random vibe sweep of a piece of electronics for your car, plane, or tank. If the platform was to be your shaker table, then what happens to the device on the floating mount?

Adding the weight to the unit changes its natural frequency but you are still then floating it so now the forces are more about the floating device than the unit itself (assuming the weighted unit is in a non-coupling frequency with the sound, and it actually causes some sort of negative performance across its circuits).

Here's an opposite view, an accelerometer in your car's air bag sensing device must be as close to 1:1 transmissibility with the vehicle "frame" as possible so it gets as pure a deceleration signal it can to tell the bags to deploy. So, in this case, stiff mounting is desired. As long as the PCB in the sensing box is not floating, then the 1:1 is achievable. And we really don't care too much what the natural frequency of the sensing device is as long as it does not cause the accelerometer to misfire on bumps (and it won't due to axis's and severity[G's]).

Since we are not banging our stereos at 10 or 20 G's, presumed negative impacts are on a much lower level but nonetheless rapid cycles. Decoupling our gear from earth is beneficial for the micro-vibrations affecting our sensitive electronics which are not built with vibration in mind like an aerospace black box, for instance.

Of course we float our devices and then put on heavy cables, especially power cables, that carry vibrations back into the unit. And all of this making the presumption the vibrations cause negative sound and they may be enough for us to "hear". 

I do isolate all my gear so each device can try and act as it was designed on the bench and given a chance to perform that way. Can I hear a difference? Not sure, but I like the tweaking aspect and avoid the math because it's a hobby and not the job. ha

Ideally, you want the system resonance to be around 3 Hz.  Compressing the springs to 50% doesn't mean much.  The springs could be compressed to 90% and the isolation affect will be the same as long as the total spring rate and mass make for a (ideal) 3 Hz system resonance.  I am able to get down to 5 Hz on my components using the Nobsound springs and they are compressed to about a 0.200" gap.  So I have no room to add mass (weight on top of my components) in order to get the resonance down to 3 Hz.  Still, 5 Hz provides very effective isolation. The isolation added clarity and detail to the music.   The added detail to the music was distracting at first but now I'm used to it and I could never go back.  

Interesting stuff guys.  @tonywinga ​​​​: What method are you using to measure the resonance in Hz on your components?

A DAC is not a turntable! You could encase it in a block of concrete - no effect upon sound quality! Same thing applies to a digital transport - immune to vibrations. The old analog ideas do not apply! 

The result of being profoundly enamored with one's own thoughts and allegiant to a familiar paradigm is that the underlying pridefulness blocks one from seeing the obvious.

My experience is very different. Vibrations affect everything to some degree. I hear quite a difference isolating my front end components as well as my amplifiers with springs. Granted my DAC and preamps use vacuum tubes but my amps are solid state. I also have experimented with different materials for the boards that the components sit on as well as having them sit directly on the Nobsound feet. I have tried granite (terrible), wood, carbon fiber and HDPE (High Density Polyethylene). Woods work well but I found the HDPE boards seemed to have a slight edge over wood under my preamps.

I have cable elevators too. Unfortunately, I could hear a difference with the cables lifted off of the floor. I made my own cable elevators on the cheap. I used electric fence ceramic isolators supported by rubber bands stretched between two dowels pressed into 4x4 wood boards. Seems to work.

I use the VibrationAnalysis app on my iPad and iPhone. The frequencies are accurate but the magnitudes are for reference only and can only be used for comparative purposes. If I were still working I would be able to compare the magnitudes with a calibrated accelerometer in the lab at work. I know that the FFT analyzer app was dead on with frequency using a calibrated tone from a B&K tone generator but I was not able to verify the magnitudes so they are reference only as well. The iPhone and app work very well and is quite sensitive. Even the lightest of footfalls from several feet away can be detected.

@tomic601 LMFAO! Read this while on a boring conference call and laughed out load un-muted.

King Spring is on vacation or hopefully banned…

@jerryg123 Glad to be of service !

@bugredmachine Finally…somebody who knows what a shaker table is ! i always dread that first test of a stacked payload and buss. Not because i thought hardware would fail but because as the “ shop guy “ clouds of FOD , etc often…appeared ..

NAIM components isolate the IEC inlet :-)

For the cable guys, activated carbon open cell foam makes an inexpensive and effective cable riser.

Jim

Nothing pisses off the lab manager quicker than parts flying off of hardware set-ups or un-godly screeching from unexpected resonances. Fun, fun, fun.

Awesome.  I wanted to ask for some advice on cheap cable risers but I just hadn't gotten around to it yet.  Thanks guys.  I've got some work to do...

For cable risers you should look at risers for rebar. Cheap at any builder's supply.

I tried it once, but may have gone a tad overboard...

DeKay

Do you need the correct springs for the device to work. The extra foam earplugs may help a little bit but don’t have the same affect as a spring

No sonic difference.

Don't forget the answer. 

Isn't adding weight a perpetual tweak exercise?

Did you make sure the Dac's feet were screwed down tight? Not to mention everything on the level?

So in general if mass isolation is so important ?? ! Why is it that Audio Note UK who sell some of the most expensive audio jewelery in the business demonstrate their wares using the cheapest most flimsy platforms / supports on offer ?. 

Cheers Johno

I have been interested in the logic and pains some go to to "isolate" components from vibration.  I will say at the start that I have NOT experimented, as that is not me.  HOWEVER, here is what troubles me.  IF vibrations are deleterious to certain components, it arrives at that component either directly through the air by sound waves, OR indirectly though the surface it sits on(and, of course, in the case of analog front end, the device itself creates vibration).  I have seen and read of many different ways of minimizing these vibrations, both with mass(ie HUGE turntables), and vibration absorbers.  What I havent see talked about, but have in my system, is everything (except amp and speakers) is enclosed in a huge, solid cabinet, which certainly helps with both of the sources of vibration...thoughts?

@gladmo ,

I have a system in a former basement bedroom and I had an intermittent hum/buzz. I made some blocks out of 2x4’s and made some trial risers for my speaker wires. The noise immediately went away. I have a second system in my family room on the main level. I added some block and I couldn’t hear any difference. But then I had no noise whatsoever to begin with.  I guess what I’m saying is not every system needs risers.

All the best.

JD

I posted a phot of my DIY cable risers in the cables $2500 thread on or about Sunday. Just to give some ideas.

I tried all of this not with a dac but a AR XA Turntable I modified. I finally found that leaving all of the nobesound springs in, so that it’s stiff, was the best option. Taking springs out only caused lateral movement, swaying and, general instability. Adding more weight would cause things to get worse. That’s my experience with these springs. 

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?

I recently placed a VPI Brick on my Bricasti M3.

Did NOT like the sonic effect.

I do use the Bricks on other components with positive results.