BOXER T2Pro/T2d

Commentary

A large monitor speaker system designed by Neil Grant.

Neil Grant is an audio design engineer for Harris Grant Associates, a British audio consultancy founded in 1985. He designed Peter Gabriel's personal studio at Genesis and worked as a consultant for the Midabert Studio at the BBC.

The T2 is designed around a mid-range driver with a diameter of 10 cm dome to ensure sound localization and to withstand harsh studio use with sound pressure of 130 dB at peak times. The driver receives frequencies from 250 Hz to 2.5 kHz and is separated from the crossover point in order to reproduce the voice naturally.
There are also two types : T2Pro with active crossover for professional studio use and T2d with passive crossover.

Mid-range 10 cm dome mid-range
The diaphragm of this unit uses a soft dome to avoid harmful resonance. In addition, 6 layers of 3 types of compounds are used to achieve a proper balance of weight and strength, heat resistance, and durability. A 13 layer structure is achieved by applying both sides of the molded fabric base.
The magnetic circuit uses a large, cobalt-based magnet 17 cm in diameter, 10 cm in depth and 16 kg in weight. The tip and top plate of the MAG net pole are made of high-purity soft iron and REMCO B high-purity low-carbon steel, a type of Swedish steel. The entire return circuit magnet is made of a single ENIAA low-carbon metal rod, which prevents the magneto-resistance caused by the return circuit junction made of two or three parts.
The flux density obtained by this magnet makes it possible to use a deeper magnetic gap. Thanks to advances in pole tip processing technology, it is possible to obtain a wide and stable symmetric magnetic field and achieve low distortion.

A 3.8 cm soft dome type tweeter is installed in the high range.
The tweeter uses a cobalt magnet 12 cm in diameter, 9 cm in depth, and 14 kg in weight.

The mid-range unit and the tweeter unit are fixed in an integrally formed 8-shaped mounting frame, and the sound pressure is raised by applying a small 360 circular non-fractional horn load.

Two 31 cm cone type woofers are installed in the low range.
This unit is selected from among all drivers tested in the United States, Japan, United Kingdom and Europe in consideration of frequency characteristics, sound quality and durability.

Each passive crossover module is independently wired and assembled for tri-wired connection, isolating the ground from one another and preventing modulation by adjacent filter sets.
The active / passive crossover is located outside the speaker cabinet to prevent residual electromagnetic radiation and coupling vibration effects.

The T2 crossover system is developed based on the target-function filter theory, in which a set of filter curves is first chosen for the target acoustic function, then the characteristics of each driver's composite filter are measured, then the characteristics of the electrical filter are calculated, and a Linkwitz-Riley crossover is employed. The crossover is set to a series of force order curves determined by a tandem Butterworth filter pair so that the sum of adjacent frequencies is -6dB.
In order to accurately measure the characteristics and phase of the driver unit in the system under anechoic conditions, we have adopted a TEF measurement method using a TEF20 TDS analyzer. The data obtained from the measurement is calculated using a filter modeling program created for this analysis, and the filter function is determined taking into consideration the speaker response. After the electric filter is modeled, another computer program is used to design an electronic circuit to determine the filter characteristics. The theoretical electronic circuit design is completed, and the final curve is determined by confirming and examining the numerical values measured on the actual driver unit.
Furthermore, in the final stage of modeling, we create a prototype circuit, conduct various tests and measurements, and confirm the sound quality and characteristics of the circuit it into a product.

The cabinet uses MDF multi-layered plates with low resonance characteristics, and the structure is determined by a computer simulation after logically carrying out cross bracing and damping in the sweet spot.
The baffle member is a chamfered, non-fractional baffle.

The dedicated speaker base is finished by traditional British furniture craftsmen.

Model Rating

Method	3-Way, 4-Speaker, Bass Reflex System, Bookshelf Type
Units, etc.	For low band : 31 cm cone x2 For Middle Area : 10 cm Dome Type For high-pass : 3.7 cm dome type
Frequency characteristic	28 Hz to 20 kHz ± 1.5 dB
Output sound pressure level	94dB/W/m
Impedance	8 Ω
External dimensions	Speaker Body : Width 522x Height 1,100x Depth 605 mm Active crossover : 483 mm wide x 94 mm high x 315 mm deep Passive crossover : 260 mm wide x 360 mm high x 540 mm deep
Weight	Speaker Body : 120.0 kg Active crossover : 7.6 kg Passive crossover : 12.5 kg