Boxe Audio Solutions Overture O303F

Three-way speaker system. Highly braced, all new Sectional-Box-in-a-Box cabinet inspired by award-winning Virtuoso series speakers. High-flow bass reflex port with highly rounded flange. ER cone mid and bass drivers inspired by our most popular Figaro series speakers, silk dome tweeter loaded with famous mini-horn. Phase-linear crossover with extra thick copper PCB and high-grade coreless copper coils. Completely reworked massive binding posts and set of spikes.

SECTIONAL-BOX-IN-A-BOX CABINET

Overture MK2 were equipped with self-locking cabinet structure which was a major breakthrough back then compared to typical non-complex cabinet structure. Working with huge potential of the self-locking cabinet we came up with another cabinet type − Box-in-a-Box structure. This type of cabinet is being used in our award-winning Virtuoso speakers and is remarkably stiff yet shares extremely good dampening properties. Seeing its flexibility to work with and potential of Box-in-a-Box cabinets in general, we decided to adapt this expensive technology to our cheaper entry-level products. Overture MK3 shares Virtuoso cabinet technology and is equipped with Sectional-Box-in-a-Box cabinet system. The whole cabinet consists of two intersecting cabinets − lightweight inner box and heavy outer box. The polyurethane layer in between the two boxes acts as dampening material. The thin but stiff inner cabinet provides the necessary support for the structure itself as well as transfers the energy of radiated back-wave to outer cabinet layers without storing energy inside the material and preventing the back-wave from being reflected to the listener. Fast energy transfer is essential in order to prevent low Q oscillations which can last relatively long and ruin precise sound reproduction.

To illustrate low Q oscillations think of the swings where energy is stored for a prolonged period and oscillations die slowly due to high mass and lack of dampening. With just one push you will have prolonged oscillations which are unwanted in the cabinets. So, transferred from an inner box, energy reaches outer box which has a huge mass to absorb the received energy (compared to the inner cabinet) and have low inner tension forces and thus high dampening properties to dissipate energy in to heat as fast as possible without generating unwanted prolonged oscillations. However, these two layers alone cannot provide efficient energy exchange and dissipation into heat. That’s why the third layer in between outer and inner boxes is so essential − a polyurethane layer joins two cabinets (which are separated by a fraction of millimetre) and provides additional dampening due to high viscosity.

This layer not only acts as an additional barrier for energy to be dissipated into heat while travelling from the inner box to the outer box but also helps outer high mass box to quickly stop its movement. To illustrate its working principle we can imagine swings being suddenly stopped with the help of a soft pillow.

MINI-HORN

All our speaker series are equipped with Mini Horn loading. This is a special treatment for soft dome tweeters. Soft dome tweeters are known to have high distortions when driven loud. Distortions rise exponentially because the centre part of dome stops moving at certain levels and frequencies thus flexes uncontrolled by the suspension. This is due to soft dome nature. Some manufacturers use an ark over tweeter’s dome with dampening material touching centre of the dome to dampen this unwanted flex. Problem with such a system occurs at different listening levels. It is simply not linear because the force which centre of the dome is rammed by dampening material is fixed and doesn’t change with tweeter’ excursion. Others use stiffening materials like titanium bracing glued to dome i.e.

This solution is far better, however, it is not without flaws as well. Yes, it stiffens the structure, but adds mass to it and thus inertia of dome spoiling impulse characteristics and sensitivity. Also, this is quite expensive to manufacture with low tolerances so that electrical and acoustical parameters wouldn’t differ between samples. Our Mini Horn, on the other hand, is much more efficient to manufacture and repeat the process with low tolerances. Mini-Horn is based on acoustical dampening just as it is in usual horns. We carefully measure at which frequencies tweeter starts to flex and emit avalanche of distortions. Mini Horn is calculated and manufactured according to desired specifications to dampen those frequencies.

The result is a proportional dampening of the tweeters’ movement. The louder it plays the more dampening it gets from its own emitted sound. It is described as acoustical impedance and is highly dependent on mini-horn shape. Another aspect is that Mini Horn adds sensitivity (because of – horn) rather than lowering sensitivity (because of restricting movement) like in previous examples.

FINISHES