Product: EVP isolation pads
Manufacturer: A/V RoomService Ltd., Pataskala, Ohio, USA
Price US$39 and US$105 each
Reviewer: Richard Varey - TNT New Zealand
Reviewed: June, 2019
My reviews have (nearly) always begun with a statement of the product vendor's value proposition, a technical explanation of the application and design principles to highlight innovation and functional features, an assessment of quality, and an account of my listening experience.
This time, it's the vision of a vanilla custard slice. It's what drew me to the Equipment Vibration Protectors (EVP) from A/V RoomService. I read of this enticing idea in a Facebook group, and at first was amused, then bemused. What was this talk about in a hi-fi forum? When I saw a photo of EVPs I realised what they are for and I knew I should try them.
It's the physical composition of the sweet treat that makes it a suitable analogy. Whilst there are many variations, the one I know from my East Yorkshire childhood is a French pastry composed of flavoured filling (pastry cream or custard) with a couple of thin layers of puff pastry that act as firm mechanical outer binders to make it handleable and give it shape. So, visually we have a sense of the EVP's construction (although the black colour is far less appetising). But what is it actually made of, and why?
These pads came to my attention soon after experimenting with vibration isolation on the advice of famed recording engineer and former Atlantic Records CD mastering engineer Barry Diament (Soundkeeper Recordings). To isolate his studio equipment, he uses rollerballs and softly inflated small bicycle tyre inner tubes to mitigate vibration in three planes of motion. The EVPs seemed to be a more practical option for my own domestic system situation.
According to the vendor's website, “Equipment Vibration Protectors are lab-proven vibration isolation feet for high fidelity playback and recording equipment, as well as guitar, bass and keyboard cabinets, microphone stands, etc. EVPs allow equipment to perform optimally, quiet the room, and prevent vibrations from being transmitted to adjoining spaces. Vibrations and resonances are no longer heard, leaving only the pure original loudspeaker signals. EVPs de-couple vibration transmission. They do so by transforming the mechanical energy into heat energy.”
The physics seems clear, although the amounts of energy and thus heat would seem infinitesimally small. It's hard to imagine these pads getting warm. I also learned from my inquiry that micro-vibration affects sound quality.
Vibration isolation controls unwanted vibrations and resonances to treat bad effects that can cause audible distortions which interfere with the performance of audio equipment, and thus gets between you and the original artistic intent. The EVPs are designed to improve clarity, dynamics, timbre, and soundstage by eliminating resonances and vibrations that compete with, mask, or interfere with the electrical signal. Laboratory tests have shown that EVPs create an at least 80% reduction in vibrations being transferred to the equipment, and/or from the equipment, by decoupling the vibrations. Vibration isolation works whether the equipment is the source of unwanted vibrations, or the subject.
A vibration isolator is a resilient support which decouples an object from forced vibration. Natural frequency and damping are the properties which determine the transmissibility of the system. The natural frequency (for the EVP, it's 3.1-12.5 Hz) is a function of the stiffness of the isolation system in conjunction with the mass (load) being supported. The purpose of tuned damping is to dissipate the unintended energy as quickly as possible. Transmissibility is the ratio of the output vibration divided by the input vibration. It is the amount of vibration passing through the system. The isolation efficiency of the EVP is conservatively >80% from about 5-14Hz (depending on EVP size, density, and load) and upwards. This means that better than 80% of the vibratory force is not transmitted to the equipment.
The EVPs are composite sandwiches. The core is a matrix of precisely heat-compressed high-density moulded glass fibres, which allows controlled air movement through the fibres. This provides viscous damping, reducing physical motion, while widening the frequency bandwidth of attenuation. As sound energy moves fibres against fibres, the friction transforms sound energy to heat energy. The annealed fibreglass is configured as a matrix of glass leaf springs bonded at all fibre intersections with a low-volatility organic compound (VOC) water-resistant binder during the moulding process under controlled heat and pressure. The material is then stabilized by multiple cycles of precompression at many times the maximum published load capacity for the specific density of the medium.
This elasticity means the pad can be compressed without the paint cracking or flaking. The formula contains low VOCs and is UV protected. The flexible paint causes slow shape-return after pad compression. Unlike other elastomeric materials, EVPs are resistant to water, mould, sunlight, humidity, age, and extreme temperatures. The EVP materials are manufactured, and the pieces hand cut and assembled, in the U.S.A.
The laboratory that tested the EVPs concluded that “solid materials transfer significant energy to whatever they are in contact with. Different solid materials transfer different energies depending on their densities, size, shape, and in conjunction with the characteristics of the material(s) it is resting on. Some frequencies are attenuated, while others are amplified. This coupling is the reason why wood, metals and even rubber can sound different, but never neutral. In addition, solid materials will deliver a unique response for every system configuration; coupling material, resting platform, equipment weight, etc.”
EVPs are designed to benefit all audio systems, regardless of price range. They're an alternative to expensive isolation equipment racks and platforms, and they don't wear out.
I noted the fragility of the glassfibre core and the need to handle carefully. It's obvious from visual inspection that appropriate compression force is what they are designed to handle, and that shear force and especially tensile force will pull the composite assembly apart. I was initially surprised by how dense and substantial they feel. A range of sizes, densities (load capacity, up to 34 Kg), and finish materials is offered for equipment ranging from small components to large loudspeakers, for shelf and floor locations.
Norman Varney recommended the ‘blue dot' (heavy/hard density) version for use with my 5.6 Kg SACD player. Four of the 2” HDs with felt finish are suitable for loads from 5.4 to 34.4 kg (the rubber option is more suitable for very heavy speakers and for outdoor and floorstanding use and when sliding to position is not appropriate). EVPs are available in 51x30mm and 102x30mm squares.
It's very important to select the right size and density, as too little or too much pad deflection will not work to decouple energy transfer. When the equipment weight is properly loading the EVP, the pad will compress somewhat, but not fully, allowing the equipment to ‘float'. When properly positioned and thus loaded, the EVP will evenly compress about 10-30% of it's unloaded thickness.
Installation is simple. I placed one under each foot of my disc player, for stability (rather than in a tripod layout, as I've done with other isolation methods), and then pressed play. The felt facilitates sliding on the shelf for best positioning. A supplied ‘bulls-eye' spirit level is used to ensure that the pads are located such that the component is level. They hardly compressed at all under the load of supporting my player. Particularly impressive is how stable the player is atop the EVPs. Try as I might to rock it by pressing on the top, front, or side of the unit, it remains solid, immovable.
All of this talk of carefully tested tweak composition and construction, and those first visions of that tasty sugary sweet sandwich, set me to thinking about what to expect from playing CDs with these pads installed. Would I hear improved clarity, dynamics, timbre, and soundstage?
My conclusion came quickly. Music played with the pads supporting the player was more clearly defined, more in focus, natural sounding. My wife commented, without prompt, that the sound was very realistic. I hadn't told her that I had changed anything in my system. Did she hear a less blurred presentation? The resulting stereo image has greater impact, and encourages turning the volume up. The effect on sound quality was both immediate and not subtle.
The image is fuller, richer, livelier, and there's more sense of recording space ambience. There's more 'energy' in the sonic image, especially in the bass range.
There's a depth that makes compelling, exhilarating listening. The sound is 'fresher'! The timbral realism is remarkable, and distinct characters of percussion, wind, and stringed instrument materials are clearly discernible. Voices are so present.
So, yes, I do hear my music with more enjoyable clarity, dynamics, timbre, and soundstage image. I try to be sceptical when I see impressive claims. How can this be true, I ask myself, then inquire rationally, before listening for myself. This damping isolation method evidently facilitates my player in operating more effectively to find and resolve the detail on the disc. Listening is compelling, drawing me into the sonic soundscape.
So surprised by the extent of the enhancement in sound quality was I, that the removal of the EVPs seemed necessary - to check that the sound reverted to what I was previously accustomed to, and yes, there was some vieling of detail, a kind of misting or defocusing, all making the music less immediate and present. So back they went! The more natural presentation instantly returned.
For quite some time, I've been besotted with playing FLAC files through a network player. Some CDs have sounded flat, especially when compared with high resolution files. Now I've fallen back in love with my CD player. I wonder how the EVPs would enhance listening pleasure further if more were added to my system. A sweet treat, indeed. They're hardly super elegant, although they are tidy, but you get sure-fire functioning without expensive extravagance.
I'm really pleased that I got to try this easy effective tweak. The EVP samples were kindly supplied by acoustic treatment specialist Norman Varney, A/V RoomService Ltd, located in Pataskala, Ohio, USA, not far from Columbus city.
SACD player: Pioneer PD 30
Preamplifier: Black Ice Audio Fusion F360
Power amplifier:Viganoni & Viganoni Sachem v2 monoblocks
loudspeakers: Audio Pro Avanti A100DC ACE-bass
Other stuff: Supra cables and power filters
© TNT-Audio 2019 Richard Varey - firstname.lastname@example.org - www.tnt-audio.com