The perfect loudspeaker would only radiate sound from its drive units and the cabinet would be completely silent. Traditional wooden cabinets have limited strength and the air pressure variations inside the cabinet, created by the drive units, causes the cabinet to vibrate, generating sound. This sound will be out of time with the drivers and results in a ‘muddled’ and distorted sound. Trying to eradicate this problem, many manufacturers have designed cabinets which resist these air pressures, employing materials such as aluminium and carbon fibre, but this does not resolve the problem.

Every time the speaker cone moves the chassis tries to move in the opposite direction, causing vibration which passes into the cabinet. Wooden cabinets flex and vibrate with this energy, converting it to heat and unwanted sound and for years this has been the acceptable solution. Ultra-rigid cabinets do not let this happen and instead this energy becomes trapped in the cabinet and over time the energy builds, finding a weak link in the system where it escapes resulting in a high frequency ringing noise.

Since inception, AVID has placed energy flow at the heart of all its designs. Every system creates vibrations, those you want and those you don’t and the key to good sound reproduction is separating those vibrations at source, making sure the ‘bad’ vibrations have a path-of-least-resistance to an ‘energy sink’ where it can be harmlessly eliminated. With our turntables this resulted in the massive Acutus sub-chassis and for our loudspeakers, we developed the Tuned Mass Technology (TMT)™ damping system, which tackles the problem of unwanted energy at source.

Through extensive experimentation, we found that having a suitable mass loosely coupled to the drive unit creates an effective path for this unwanted energy. With all other paths now ‘High Impedance’, the easiest path for energy flow is to the TMT™ damper. Being decoupled, the damper can freely vibrate, dissipating any energy internally resolving the problem BEFORE it even leaves the drive unit, so the cabinet does not need any specific treatment itself. The benefit is instantly obvious with a clean, focused sound, greater clarity to the music and vocals becoming etched within a transparent soundstage.

Compact in size, but huge on performance, the Reference Four should not be underestimated. Resolving beyond expectation the two major problems that plague loudspeakers, drive unit vibration and internal air pressure, the cabinet is hand crafted from precision machined 15mm thick aluminium plate, this preventing any flexing from internal air pressure that is common with wooden cabinets. The drive units are clamped to the front baffle using our exclusive metal compression plate, equally pressurising the complete circumference rather than the traditional less rigid screw fixing and dissimilar to other metal loudspeaker designs, ours are devoid of the masses of internal bracing unsuccessfully trying resist cabinet vibration. Utilising our Tuned Mass Technology (TMT)™ damper, unwanted drive unit vibrations are removed at source, immediately lifting a veil of distortion, and leaving crystal clear sound.

Maintaining the reflex ported design principle, this is implemented in a vertical, downward firing position under the cabinet. Being at the forefront of technology, we developed our 360˚ Conical Bass diffuser. At the exit of the port, we designed a curved deflector which re-directs the airflow to the horizontal plane and spreads it over a full 360 degrees which reduces the pressure, reducing the risk of unwanted noise. This design allows a staggering low frequency response down to 30Hz and makes the loudspeaker amazingly room tolerant and easy to accommodate in almost any small to medium-sized living room.

Preserving the ultimate transparency, the identical 4” Tweeter used on all our Reference loudspeakers is employed within our Reference Four. With a powerful Neodymium magnet and 1⅛” diameter Hexatech™ aluminium voice coil and titanium former, it is rigidly coupled to the front baffle which is purposed machined with an Improved Dispersion Recess (IDR) design, a shaped inset which increases the high-frequency output of the off-axis response.

Acuflex™ Technology, a specially engineered damping compound is applied to the soft silk dome of the tweeter creating a diaphragm that exhibits controlled cancelling break up, or accurate flexing, meaning each break-up mode is counteracted by another in the opposite direction. This cancellation of break-up modes leaves nothing, but a pure and natural sound.

Built into the Uniflow™ aerodynamically designed basket, the 6” Bass driver offers an awesome bass performance and utilising our Tuned Mass Technology (TMT)™ damper to remove unwanted vibration, the Damped Polymer Composite Cone remains distortion free. Unlike other loudspeakers that suffer from vibration issues and try to mitigate the problem using trendy cone materials, AVID have resolved the vibration issue at source, just leaving a stunning clarity of sound.

Both Bass and Tweeter exploit the External Voice Coil (EVC)™ Technology, a design that moves the magnetic drive system to within the voice coil, eliminating stray magnetic flux by effectively directing all the magnetic energy to the voice coil, improving heat dissipation, and reducing cone breakup for a flawless performance.

Crossovers are a hidden component within the loudspeaker, dividing unfiltered audio signals from the amplifier and suppling each driver with the signal range it was designed to reproduce and is essentially the brain of the loudspeaker. Limiting the number of parts in the crossover reduces distortion with component selection and quality control being vital to achieve the best sound. Essentially there are three types of component within the crossover design: Capacitors, Inductors and Resistors. The importance of selecting the correct specification and value of each component cannot be understated, each working in unison to obtain the highest performance. After using sophisticated computer simulation to establish these values, final component selection is done through extensive listening tests.

Exclusively employing ClarityCap™ capacitors for all Reference loudspeakers, their CopperConnect™ technology dramatically reduces grain boundary crossings and signal path resistance and using higher rated voltage versions greatly reduces Equivalent series resistance (ESR) allowing the capacitor to achieve new levels of audio performance. Air Core Inductors offer significant subjective audible improvements over less expensive alternatives. AVID inductors are wound with 1.25mm self-bonding enamelled wire on air core plastic rectangular bobbins. Using this heavy gauge wire achieves a lower DC Resistance (DCR) for better Bass control and was chosen purely on the basis of superb sound quality.