Descrição
ESTADO CONSERVAÇÂO 9/10
Overview
The Calliope drive units were made to TAG McLaren Audio’s specification by Vifa of Denmark. The 150mm bass/midrange driver had a die cast magnesium chassis, woven glass fibre cone and a phase plug. The 20mm silk dome tweeter had a custom faceplate to minimise the distance between the bass/midrange and the tweeter.
The ideal loudspeaker enclosure would require a stiff, dense, resonance free cabinet, without parallel structures, sharp edges or symmetry. This would minimise diffraction and coloration resulting in an unparalleled transparent and spatial sound.
‘Composite Sandwich Technology’, developed for the F1 AvantGarde loudspeakers, used a wet lay-up of gel-coat glass fibre providing a very stiff, dense, resonance free cabinet. The complex curves in the cabinet walls avoided internal symmetry to prevent standing waves and eliminate sharp edges from the external form to minimise diffraction.
The upper bass enclosure had a rear-firing, gas-flowed reflex port moulded into the rear of the enclosure while the lower bass enclosure used a downward firing, gas flowed reflex port which was diffused through the aperture created between the underside of the enclosure and the base plinth.
Composite materials were too expensive to be used in the more affordable Calliope range of loudspeakers so an innovative construction using aluminium was developed. Aluminium, as a raw material, has an inherently high stiffness-to-weight ratio affording the intrinsic structural rigidity required for the loudspeaker enclosure.
In order to create the curved form of the enclosures, the aluminium was pre-heated to a molten state and then forced under pressure through a die tool. The formed extrusion length exits the die and is carefully cooled to maintain the desired geometry created by the die tool and cut to length. This allowed accurate design of the form and wall thickness of the extrusion.
The top and bottom end caps were also manufactured from diecast aluminium and were tensioned by stainless steel rods with the extruded enclosure compressed between them. This produced an immensely strong, self-damped assembly free from undesirable resonant modes.
The crossovers in both the F1 and Calliope loudspeakers used high-grade electrical components selected for very low loss and high precision. Capacitors were audio grade polypropylene and the inductors were selected for minimum loss and very low distortion, comprising ferrite cores wound with Oxygen Free High-purity Copper (OFHC). Gain matching of drive units is usually achieved using series resistors but this method introduces distortion due to the thermal non linearity. To overcome this deficiency, auto transformers were chosen with the added benefit of tighter control of the filter slope.
Specifications
- Low Frequency loading
- Bass reflex, low velocity air flow duct
- System Type
- Two-way
- Mid Range
- Magnetically shielded 150mm die-cast magnesium chassis, woven fibre diaphragm incorporating phase plug
- High Frequency
- Magnetically shielded 20mm wide directivity silk dome
- Low Frequency Extension (in-room response)
- -10 dB @ 35 Hz (-3dB @ 51 Hz)
- Response Uniformity (anechoic response)
- 80Hz to 20kHz, ±1.5dB
- Sensitivity
- 87.5dB, 1m, 2.83v
- Load Impedance
- Nominally 6 Ohms, moderate reactive content, Z min 4.3 ohms
- Alignment
- Acoustic 4th-order vented, Quasi-Bessel
- Power handling
- 100 W continuous into 8 W on unclipped programme
- Maximum level
- 109dB @ 1m (in-room)
- Directivity
- Near constant angle directivity , for up to ±45 degrees lateral 300Hz to 15kHz +2.5,- 4dB)
- Distortion
- T.H.D. 1% or less at 90dB, 100Hz to 25kHz
- Wiring
- OFHC single wire inputs terminals. Minimised coupling between driver sections, band matched driver cables
- Crossover build
- Hard-wired component connection
- Stereo presentation
- Direct radiating
- Grilles
- Acoustically transparent, non-ferrous grille
- Enclosure technology
- Tensioned aluminum extrusion
- Dimensions
- (HxWxD) 330 x 200 x 300 mm
- Weight
- 7 Kg
