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Isolation Base
Clarity starts at the floor.
Listening to music should be enjoyable and effortless, and that takes clarity. For many years we have decoupled turntables and other components from the floor and the rack. The loudspeaker itself is the main source of vibration in a listening room, so we looked for a way to break that feedback loop too, as part of the loudspeaker rather than as an accessory. The result is the Isolation Base of our Evolution line.
01 · Why it matters
The quietest details are very small.
Ringing and resonance
We have measured vibration on our cabinets for years, to improve the bracing inside. One result is always the same: a loudspeaker decoupled from the floor rings dramatically less. No matter how rigidly it is built, the cabinet stores less energy when it is isolated the right way.
Clarity
As a note decays, the cone of the driver moves by a fraction of a micron. Ringing of the cabinet, vibration from the other loudspeaker and structure-borne noise from traffic can be far larger than that. They mask the finest details of the music with noise. Lower that noise floor in the whole loudspeaker, and clarity rises.
Coupling and mass
Some say that an isolated loudspeaker loses attack, because the cabinet moves back as the cone moves forward. Newton’s third law puts this in proportion: with a cone of 40 grams and a loudspeaker of 40 kilograms, the loss is one thousandth of the energy, well below 0.01 dB. Small compared with what isolation gains.
Structure-borne noise
What happens in the loudspeaker also happens in your building. Energy passes into the floor and causes ringing, resonance and distortion; anyone who has heard a phone vibrate on a table knows the effect. With the loudspeaker isolated, far less bass travels through the floor into other rooms.
02 · How it works
A wideband filter for vibration.
During development we tried the solutions already on the market. Some worked well, but only within a narrow frequency band, and we did not like what that did to the sound. So we designed our own.
The Isolation Base works as a wideband filter. A plate machined from 10 or 12 mm aluminium takes up as much energy as possible from the cabinet and passes it into the damping feet, where it is absorbed before it reaches the floor. Energy coming back from the floor is absorbed on its way back, too.
Each base is matched to its loudspeaker, so there is nothing to adjust and no guesswork. The loudspeaker stands firmly, and the feet are height-adjustable for floors that are not perfectly level. The bases are machined in-house in Switzerland, in black or natural anodised aluminium.
The floorstanding EV Reference models come with their Isolation Base. The EV 350 Ref. is often placed on a shelf or sideboard, where it needs none; for free-standing placement, its precision-machined aluminium isolation stand is available separately.
03 · Measurements
What the measurements show.
One EV 900 Ref., four ways to stand: directly on the floor, on spikes, on the Isolation Base, and on an established isolation platform from another maker. An accelerometer measured the vibration on the floor and on the back wall of the cabinet, always at the same spot, with CEA-2010 bursts from 20 Hz to 1 kHz, a test signal closer to music than a sine sweep.
Into the floor.
Standing directly on the floor, the loudspeaker passes all frequencies into it, plus resonances that were never part of the test signal. Spikes do not cure this; they pass some frequencies more and others less, which adds colouration. On the Isolation Base, only a small signal remains at 250 Hz, 500 Hz and 1 kHz: at 250 Hz the level is 88 % lower, and below 200 Hz nothing is measurable at all.
On the cabinet.
Thanks to the bracing inside, the cabinet shows almost no resonances even on the bare floor. The Isolation Base lowers its vibration by a further 45 to 55 %, evenly across all frequencies. On spikes, most values run off the scale and new resonances appear at 60, 80 and 100 Hz; with the 20 Hz burst, the Isolation Base leaves 85 % less energy in the cabinet than spikes do.
Over time.
For clarity, what counts is how long a tone keeps ringing after the signal has stopped. The time-frequency analysis from 20 Hz to 20 kHz shows it: on spikes, standing waves around 20 Hz and from 50 to 80 Hz hardly decay, because energy bounces back from the floor into the loudspeaker. On the Isolation Base, the impulse dies away much faster, and across most of the spectrum the level is about 55 dB lower.
At your listening seat.
Measured with a microphone at the listening position in a normal room, the frequency response does not change, and it should not. The difference shows in the time domain: less additional energy in the room and a faster decay, without any acoustic treatment. You hear it as clearer bass and midrange, and details that are easier to follow.
04 · Questions and answers
Questions we are asked.
Aren’t spikes better?
Not in our measurements. Spikes couple the loudspeaker to the floor at a few points: some frequencies pass more, others less, and energy returns from the floor into the cabinet. The Isolation Base absorbs it instead, evenly across the spectrum.
Does it change the sound?
It does not change the frequency response. It removes what does not belong to the music: ringing and smearing over time. That is where the clarity comes from.
Does it help my neighbours?
Yes. Far less energy reaches the floor, so far less bass travels through the building into other rooms.