ELAC 213-4 π

Commentary

A floor-type speaker system equipped with a 4 π ribbon tweeter.

A 4 π ribbon tweeter, a 15x300mm ribbon type tweeter, is installed in the high range.
This unit is designed to prevent high-frequency loss that is a problem in an actual room. It is a ring-shaped non-directional ribbon tweeter to compensate for sound absorption loss above approximately 4 kHz. The diaphragm is an ultra-lightweight 6-micron aluminum diaphragm, and moreover, it is highly rigid because it is not flat.
This unit has not only wide directivity, but also excellent pulse response, high input resistance that breaks the common sense of ribbon type, and has realized a tough structure. In addition, the directivity in the vertical direction is improved by adopting the horn shaped flange, and it has a unique shape that symbolizes 4 π (free space) technology.

Two 20 cm cone type woofers are installed in the lower range.
In the mid - and low-frequency range, sound reflection in the room impairs the performance and sound quality of speakers. To solve this problem, Airac analyzes the effect with a computer and has established a method to prevent harmful reflection from floors and ceilings.
The 213-4 π system uses a double woofer system that optimizes the mutual distance and height relationship. The vertical directivity is limited by canceling each other's reflected waves. Each unit is housed in an independent rear bass-reflex chamber. It is a staggered loss system that is responsible for up to 800 hz and 4 khz, respectively.

Equipped with 3.7 cm soft dome type skoker in the middle area.
This unit and the upper woofer are time-delayed with respect to the lower woofer. This delays the middle and high wave front so that the main axis of orientation is slightly raised to match the height of the listening point. This effect is exactly the same as the effect of tilting the baffle backward. It is created by electronics and the phase relation with the lower woofer is precisely adjusted.

In order to eliminate the influence of the room that cannot be covered by the speaker unit alone, Airac's original time-delay crossover network is used in the network section.
This network adjusts the time axis in units of milliseconds to cancel reflected waves, and the 4-way unit, which maintains constant directivity and is uniformly controlled from low to high frequencies, is designed to operate like a single unit with a wide band.

The enclosure has a black semi-gloss finish.
There was also a wood finish version as a made-to-order model.

Model Rating

Method	4-Way, 4-Speaker, Bass Reflex System, Tall Boy Type
Units Used	For low band : 20 cm cone x2 For Middle Area : 3.7 cm Dome Type For high-pass : 1.5x30cm ribbon type (non-directional)
Crossover frequency	750 Hz, 800 Hz, 4 khz
Frequency characteristic	26 Hz to 35 kHz
Impedance	4 Ω
Max Input	170W
Output sound pressure level	84dB/W/m
External dimensions	Width 250x Height 1,000x Depth 315 mm
Weight	28kg