AR-112/45

AR-112/45 is a 2-way, 2 element full range speaker

 

High-frequency section is a horn loaded design, a 45 o (H) X 45 o (V) conical exponential horn is specially designed for AR-112/45. The exponential horn was chosen due to its minimal changing rate of cross section. We expect the acoustic impedance of a horn be kept constant pure resistance for a widest possible frequency band. Exponential horn fulfilled this requirement. The materials of the horn is fiberglass reinforced plastic.

 

The enclosure is made of 18mm (11-ply) birch plywood. All joints are tenon and mortise of Chinese tradition plus screws and adhesive to ensure the rigidity and durability.

 

Many domestic and imported speaker enclosures using medium density fibre (MDF) board to reduce cost, but MDF has a total weakness. It soften when moisten and loss its rigidity. IBO rather uses expensive birch plywood to build the enclosures to ensure its strength and rigidity no matter used indoor or outdoor, rain or fine. (See Figure 3)

 

The enclosure is heavily braced internally and a black powder-coated perforated steel mesh grille protects the drivers from damage. The finishing is in black semi-matt textured environmental friendly paint. A rear connector plate fitted with two Neutrik Speaker NL4MP connectors for amplifiers and for loop-in and loop-out to additional enclosures. (See Figure 73)

Figure 73

The Components

The LF unit is a L12/75/09Z 12-inch cone type developed by iBO.

  • The cone of L12/75/09Z is eight and rigid, the surround is soft, has better LF response.
  • The materials of the cone is specially formulated pulp with fiberglass and wool
  • Magnet is made from high flux y30 strontium ferrite and the magnetic structure weights 6.15kgs

The diameter of the voice coil is 3-inch (75mm) edge wound with flat aluminum wire on a Kapton former. (See Figure 74)

Figure 74

HF unit is a H3/75/03Z compression driver. The H3/75/03Z is developed by iBO featuring:

  • The diaphragm is made of titanium and its surround is Mylar. The voice coil is edge wound with feat afumimium wire, (See Figures 75 and 76) the diameter is 3-inch (75mm)

Figure 75 Figure76

  • The diameter of the throat is 1.4-inch (35mm)
  • The slits pattern of the phase plug is circumferential.
  • y30 high flux strontium ferrite is employed and the magnetic structure weights 6.05kgs

 

Without the phase plug, the radiation from the center of the diaphragm or cone and the radiation from of the edge reach the throat at different time as the distances are different, as well as phase difference .

With the phase plug, the radiations from the center and from the edge are traveling at equal distance. When these radiations reach the throat, they are in phase. (See Figure77)

Figure 77

The slits pattern of the phase plug is circumferential. (See Figure 77)

Figure 77A

Crossover Network

The sensitivity of AR-112/45’s high frequency component (110 dB w/m) is much higher than the low frequency component (97 dB w/m). The difference is more than 10 dB. If a build-in passive crossover network is employed, the sensitivity of AR-112/45 can only be 97 dB w/m. It does not make sense to sacrifice the 10 dB of the high frequency component. Besides, any passive crossover network have an insertion loss. The actual sensitivity of AR-112/45 would be less than 97 dB w/m. We decided not to employ passive crossover network for AR-112/45 and recommend using external speaker processors that incorporate delay and equalization functions such as iBO D026(2 in, 6 out) digital speaker processors.

 

Applications and Technical Specifications

AR-112/45 may be used in conjunction with any of AR-112/64, AR-115/64, AR-115/45 or AR-153 plus AR-215B or AR-218B to make up a 3-way or 4-way array for fixed installation sound reinforcement system of any scale such as theaters, multi-function hall and large disco or used individually as stage side fill.

 

Technical Specifications and diagrams (See below)

FREQUENCY RESPONSE

50 Hz ~ 18 KHz (± 3 dB )/35 Hz ~ 22 KHz(-10 dB)

SENSITIVITY (1W/1m)

HF:110 DB(1.5kHz~20kHz)

LF:97 DB(50Hz~1.5kHz)

NOMINAL IMPEDANCE

HF/LF:8/8 Ohm

POWER RATING

HF/LF150/400 W (AES)

CROSSOVER FREQUENCY

1.5 KHz

LF COMPONENTS

1×12〞woofer (3″voice coil)

HF COMPONENTS

1×2〞exit compression driver(3″voice coil)

 

NOMINAL COVERAGE

45゜(H) ×45゜(V)

CALCULATED OUTPUT (MAX)

HF:132 dB SPL, 138 dB SPL peak

LF:123 dB SPL, 129 dB SPL peak

DIMENSIONS (H×W×D)

670×420×420 (mm)

WEIGHTS

34 (kg)

CONNECTORS

2 Neutrik NL4MP connectors

SUSPENSION HARDWARE

Flying tracks (side)

Flying hardware set (rear)

 

 

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