Bose Panaray MA12 Технічна основа та обговорення - Сторінка 23

Переглянути онлайн або завантажити pdf Технічна основа та обговорення для Акустична система Bose Panaray MA12. Bose Panaray MA12 36 сторінок. Modular line array loudspeaker
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OTHER LINE-SHAPED SOURCES

the last section, the unique decisions and choices Bose made in designing the innovative

MA12™ modular array were discussed. However, there are other line-shaped sources already

available. How do they compare to the MA12 ?

Column speakers

line-shaped sources have been around for a long time. A number of well-known

OME

manufacturers have developed versions, called column speakers, as early as the 1940's. The

speakers had limited frequency response and output. In other applications where better tonal

balance and higher levels were needed they simply could not be met by these column

speakers. None could be considered high performance speakers by today's standards.

Sources using electrostatic, ribbon, or planar magnetic transducers

class of line-shaped speakers uses electrostatic, ribbon or planar magnetic

NOTHER

transducers. In general, these transducers do not produce a full-range frequency response, but

only covers from about 3-500Hz and up. To cover the range of lower frequencies up to about

300-500Hz, the transducers are augmented by traditional sources typically using woofers in a

sealed enclosure at the bottom of each speaker.

In some implementations, the ribbon emits sound both to the front and the back, so high-

energy sound from the rear of the speaker is directed away from the audience and onto wall

surfaces where reflections add to reverberation and degrade clarity and intelligibility. Many

of these speakers, while looking promising on paper, are not designed for professional

applications, require a base to extend the frequency response, and radiate equal amounts of

sound to the rear.

DSP-based arrays

THERE

another class of arrays that are using digital signal processing (

steer the speakers' radiation patterns. Most of these arrays use 4" (10.2 cm) or larger

transducers. The drivers are either spaced closely in a line, or in a scheme where spacing

varies. The speakers have built in multi-channel signal processing and amplification.

There are some obvious differences between these arrays and the MA12 . First, these

speakers are using larger drivers resulting in an appearance that is significantly wider than the

MA12 . The larger drivers also have narrower horizontal coverage, which can be a

disadvantage with audiences located close to the speaker.

The biggest difference is these speakers' use of

array, and which also makes the cost much higher than the MA12 . Drivers get different

signals and hence require their own signal processing and amplification. This makes it

possible to steer the radiation pattern at middle and higher frequencies. For example, the

Bose

MA12™ Modular Array: Technical Foundation & Discussion

to control the radiation pattern of the

DSP

Page 23 of 36

) to control and

DSP