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Vibration control for better performance

Though this article was originally written for audio enthusiasts and their playback systems, I've applied the same principles in the studio and have enjoyed the same benefits.  Since this is a subject I've not seen mentioned at all in recording circles, I thought it about time.  Everything within applies just as much to the studio as it does to the living room.

My suggestion to all readers is to NOT take me at my word but to experiment for yourself and please let us know of your experiences.  I hope what you are about to read provides food for thought and increased pleasure in your work.

The best advice I can offer to someone looking to upgrade their audio or video system is "Don't buy any new components".  This may seem strange at first, in view of what the popular journals and websites are saying.  Each month they feature the latest advances and write glowing reviews of dozens of products.  Won't a new amplifier or a new set of speakers represent an improvement in system performance?  Maybe.  Maybe not.

Many audio enthusiasts and equipment reviewers are frequent upgraders.  For a large number of these people, the reason for the frequent equipment changes is an ultimate lack of satisfaction with gear that initially impressed them.  The magazines and websites contribute to this cycle by creating the impression that purchasing the products of their advertisers will achieve the sought after performance improvements.  This doesn't necessarily mean these publications are corrupt or fear advertiser reprisal.  Even on the ad-free sites, many of the writers seem to buy into what the manufacturers tell them without question.  Often the New Products sections as well as the content of the reviews themselves seem more like direct quotes from the marketing literature.  Many of the contributors found on the Internet forums have also become adept at quoting marketing claims as if they were Truth.

What almost none of these experts are telling the listener is that some of the most significant upgrades, the most meaningful performance improvements can be achieved without buying new components.  Further, without these most significant upgrades, any potential performance gains from new components are minimized and obscured.  The listener ends up on the equipment trading merry-go-round or worse, ends up losing out on the pleasure their system might be capable of delivering.

What's a music or movie lover to do?  It comes down to this:
If you don't know what your present gear is capable of, you have no way of knowing what any possible replacements can do.  In order to know the capabilities of your present gear, you have to consider its implementation.  By this I simply mean that where your equipment is located within your room and what you place the equipment on will have a profound effect on how it performs.

Some people already understand this to a degree as it relates to loudspeakers.  They understand that a loudspeaker won't begin to show what it can do unless it is placed well away from large surfaces like walls.  This means bookshelf speakers must not be placed on a bookshelf but on stands that will keep them off the floor and can be placed away from walls.  It also means old style corner placement is wrong as it will put the speaker near the junction of two walls, possibly near the floor or ceiling as well.  Move them out of the corners and hear them sound "more expensive".  The difference won't be subtle.

Correct speaker placement is a start but only that.  The room itself contributes significantly to the ultimate sound you hear but that's a subject for another article.  Here, we're talking about your components and how to help them achieve their best performance.

I used to believe the designers and manufacturers of a given component gave me everything I needed to achieve maximum performance in that box the component comes in.  I thought all I had to do was put the components on my shelf, connect the appropriate cables and turn them on.  Thanks to some experimentation on my part, I no longer subscribe to this.

What's shakin'?

What I've found is that all of our components are being substantially inhibited from delivering their best because they are subject to external vibrations.  By far, the most sonically and visually degrading are those vibrations in the ground that enter the component via its feet.  These seismic vibrations (the ones very low in frequency and amplitude, so tiny we don't even normally feel them) are creating spurious signals within the sensitive circuitry of your components.  These spurious signals mix with the real music and video signals to distort them, hardening the treble, thinning the bass, muddying the soundstage and annihilating dynamics.  Seismic vibrations add grain to video pictures, ruin color purity and contrast and soften focus.

I'm still having a bit of trouble accepting that the ocean tide or the wind or a truck changing gears 1/4 mile away has such a profound effect on the performance of my audio and video gear.  What I have no trouble with is the results of isolating my gear from these effects.  The performance gains in every parameter I can think of are clear, consistent and repeatable.  Frequency extension into the treble and downward in the bass is improved.  Stereo imaging gets better focused.  The soundstage takes on greater proportions.  Dynamic swings both large and small are more like real life.  Overall, there is a much greater sense of the system getting out of the way, leaving the listener with a considerably increased sense of contact with the recorded event.  The color, contrast, focus and purity of video signals is improved.  None of these changes can be described as subtle, as they are very easy to perceive by all listeners and viewers.  Best of all, the differences between sources (different recordings and different movies) are more easily discerned.  This is important because recordings and movies vary in quality and the ability to perceive qualitative differences speaks of the resolving capabilities of the playback system.

Seismic isolation.  Those two words are the key to knowing what your components can and cannot do.  The benefits extend to loudspeakers as well.  In fact I have yet to find a component that doesn't significantly benefit from seismic isolation.  Some, like source components (for example CD and DVD players) and loudspeakers show the largest improvements but even power strips benefit from seismic isolation.  After all, they too contain electrical signals which are subject to degradation by seismic interference.

How do you achieve seismic isolation?  You have to "float" your components.  Floating is accomplished with the use of simple mechanical low-pass filters.  Mechanical low-pass filter is a fancy way of saying a spring with a resonance frequency in the seismic range.  Every spring has a resonance frequency, which is the number of times it bounces when compressed and released.  If we could float our components and speakers on some type of springs with a resonance frequency of only a few cycles per second or less, we'd be able to prevent the damaging vibrations from entering those components and the gear would be free to perform its best.

Vertical springs aren't enough though.  Vibrations can exist in the horizontal and rotational planes as well.  We need to float the gear both vertically and horizontally.  This is not at all a difficult thing to do and the performance benefits will make you wonder why this isn't much more widely discussed.  More importantly, the benefits will allow you to know the capabilities of your present components.  I guarantee you will be very pleasantly surprised.  In addition, seismic isolation will allow you to judge if a potential component replacement can achieve a meaningful performance improvement.

As awareness of the negative impact vibrations have on component performance increases, so does the opportunity for commerce.  The market is flooded with accessories touted as isolation devices.  There are all sorts of footers (i.e. adjunct feet) from Sorbothane hemispheres and vinyl pods to cones made of various materials.  There are tiny trampolines, so-called magnetic levitation platforms and a host of equipment platform and rack designs all of which claim to isolate your gear from vibrations.  While some of the roller bearing type footers work, most of the other devices merely change the sound by creating a new set of colorations which some listeners confuse with a performance improvement.  These folks ultimately find themselves riding the old merry-go-round again.  Similarly, there are a few platforms and equipment racks which utilize air bearings.  Most of the others on the market merely ensure that your components are not on the floor.  Any of these can be checked very simply.  If they don't bounce at a very low rate, they aren't going to act as mechanical low-pass filters and consequently, they're not going to isolate the components they support from the frequencies that will cause the damage.

There are two simple mechanical low-pass filters you can make in order to achieve seismic isolation in multiple axes, that is, seismic isolation in the vertical, horizontal and rotational planes.  A simple air bearing made from a minimally inflated bicycle tire inner tube will provide seismic isolation in the vertical axis.  Roller bearings will provide it in the horizontal and rotational axes.

After much experimentation, I created my own roller bearing design, Hip Joints© which, partly because of their lower resonant frequency, outperform the commercially available variety.  Similarly, while there are some equipment racks and platforms which utilize air bearings, I created my own design, the Enjoyyourshelf© rack, which features a fully independent suspension for each shelf.  (The world's first piece of furniture with a fully independent suspension!)

Roll your own

In order to provide a means of sampling what seismic isolation can do for your system, what follows are instructions for making your own equipment supports.  Items 3, 6, 7 and 8 pertain to roller bearings.  These can be used without air bearings to provide horizontal and rotational isolation only.  Air bearings can be used to provide vertical isolation only, as in those commercial racks and platforms which use air bearings.  Best results however, will be attained by using a combination of these to achieve multiple-axis seismic isolation.

1. Get yourself a bicycle tire inner tube for about $1.99.  I use 18" inner tubes.  The larger the circle described by the inner tube, the easier it is to balance the gear atop it.

2. Obtain a piece of plywood to use as a platform on top of the inner tube.  I use 1" maple ply measuring 20" by 20".

3. Go to a crafts store and purchase 3 wooden, usually pine, Easter egg holders and some marbles for a total of less than $2.

4. Place the inner tube on your shelf.  Inflate it only enough to hold the component up off the shelf.  Too much air and you won't get the benefits.

5. Place the plywood on top of the inner tube.

6. Place the three Easter egg holders on the plywood platform in the largest equilateral triangle that will fit under the gear you are going to support.  I suggest trying your CD player first, though the benefits will add up as you float your other components as well.

7. Place a marble, or even better, a ½" steel ball bearing, in each of the Easter egg holders.

8. Carefully place your component atop the marbles, so they alone support it, holding it up so its own feet do not make contact with the plywood platform.

You have now constructed, for a cost of approximately $5, a simplified Enjoyyourshelf©.  Of course it can be improved upon for added expense but the point here is to demonstrate and share the concept.  If you like what you hear, you can always take the design further.


Now you know why my best upgrade advice is "Don't buy any new components".  The application of seismic isolation can turn your existing system into a set of "new" components.

Happy Listening!

P.S. While digital devices show some of the greatest performance benefits when seismic isolation techniques are employed, the effects are cumulative and system performance improves as each additional component is "floated".  Your loudspeakers too will show performance improvements, perhaps even more so than your digital devices.

Finally, a caveat:  In my experience so far, there has been only one system that did not show the performance benefits I'm describing.  It turns out that system had two characteristics which must be dealt with first, evidently even higher priorities than vibration isolation:

First, it was connected to a garden variety, el cheapo terminal strip rather than a good AC conditioner.  Second, all equipment cables (line level, speaker and AC) were gathered in a jumble behind the racks.  All three types need to be properly "dressed", to borrow a term from our friends "across the pond" in Great Britain.  That is, they should be separated from each other.

So what I learned from that experience is that "dirty" AC and improper cable routing can obscure even the great benefits provided by vibration isolation.  Only when there is clean AC and proper cable routing has been attended to will the benefits of vibration isolation be evident.