PH-118B

PH-118B is a very compact subwoofer housing a single 18-inch driver, the frontal of the cabinet is about the same size as the 18-inch unit. (See Figure 137)

The enclosure

The enclosure is of phase inverted (or vented) design. The advantage of this design is that sound wave radiated from the rear of the speaker be in phase with the sound wave radiated from the speaker front by proper phase adjustment after passing through the vent. The vent itself functions as an additional radiator is this case, and its radiation can add constructively to that of the speaker over certain frequencies. It requires less speaker excursion and therefore reduced amplitude distortion for a given acoustic output in the lowest portion of its usable bandwidth. This effect is most noticeable for frequencies in the neighborhood of the system lower cutoff frequency.

 

For the same lower cutoff frequency, the enclosure can be made smaller and due to this reason, the air within the enclosure acting as an air cushion at very strong transient signals. (See Figure 138)

Figure 138

The component

PH-118B housed a single L18/100/11Z 18-inch cone type driver

Single L18/100/11Z drivers are used in PH-118B and developed by iBO specifically for horn loading

• Frame is die cast alloy
• The cone is a special formula of pulp and glass fiber. The depth of the cone is rather shallower with reinforcement ribs for better reproduction of low-frequency
• Surround and spider are stiffer to increase the mechanical stiffness
• The cone is treated with inflammation resistant agent
• The diameter of the voice coil is 4-inch edge wound with flat copper wire on a Kapton former.
• The magnet is made from y30 high flux strontium ferrite weights 10.75kgs. (See Figure 139 and 140).

Figure 139

Figure140

The Crossover Network

Normally there is no built-in passive crossover network is a subwoofer or perhaps only a built-in low pass filter but even a low pass filter could cause phase problem and there is insertion loss. For these reasons, the PH-118B has no built-in passive crossover network nor low pass filter. It is recommended that all PH series speakers should be used in conjunction with external speaker processor with delay and equalization functions such as iBO D-24 (2in 4out) or D-48 (4in 8out) digital speaker processor.

 

Applications and Technical Specifications

PH-118B can be used in conjunction with any of the PH-110, PH-112 and PH-115 as the main speaker of small to medium sound reinforcement system for assembly hall, multi-function hall or other audio visual activities or used as stage monitor or as auxiliary speaker for a large sound reinforcement system.

 

Technical Specifications and diagrams (See below)

FREQUENCY RESPONSE	35 Hz ~ 260Hz (± 4 dB )/28 Hz ~ 1KHz(-10 dB)
SENSITIVITY (1W/1m)	102dB(40Hz~200Hz)
NOMINAL IMPEDANCE	8 Ohm
POWER RATING	600W (AES)
LF COMPONENTS	1×18〞(4″voice coil)
CALCULATED OUTPUT (MAX)	130 dB SPL, 136 dB SPL peak
DIMENSIONS (H×W×D)	540×580×700 (mm)
WEIGHTS	45 (kg)
CONNECTORS	2 Neutrik NL4MP connectors

 

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