X-Treme Audio HPS - Manual (Page 2)

HPS
HIGH POWER SUBWOOFERS
User’s manual
CONTENTS
1. Introduction
2. “ λ”, directivity, combing
3. Combing and mutual pairing
4. Pairing with the environment
5. Hence, some pratical ideas...
6. Examples and simulations with the X-Treme Installer
7. X-Treme Subwoofers: product catalogue
1. Introduction
This brief guide aims to take a closer look at some of the concepts
related to the features of
subwoofers and to verify some of their
effects in the field, especially how they interact with one another
and with the environment. Software and trials carried out at
Sound
Corporation’s metrological laboratory (see Figure 1) will be used to
confirm and add to these concepts. Although specific recommenda-
tions on the “cut” and “alignment” of subwoofers may be of primary
interest, they go beyond the scope of this study.
Our aim is to use a more informative approach to explain not only the
physical phenomena associated with subwoofers in the environment
where they are located, but also partly to explain them. Thus, our
aim is to think “upstream” to the installation and then compare the
suggested concepts with the acoustic measurements of an actual
installation.
For this purpose, we have to imagine a generic subwoofer model
resembling a “black box” (that is to say, forgetting about construc-
tion techniques) measuring roughly one metre per side and whose
acoustic pressure remains within a range of frequencies below 100
Hz, with basically omni directional emission: a sort of “monopole
source,” but with real dimensions.
Fig. 1 Metrological laboratory at Sound Corporation
2. “ λ”, directivity, combing
All the acoustic specifications of a subwoofer (or “ sw”) stem from
the size of the wavelength it produces, conventionally known as λ,
(lambda). Taking our definition of a sw, we can estimate that λ will be
no less than 3.4 m (the wavelength at a frequency of 100 Hz) and will
reach about 17 m (the wavelength at a frequency of 20 Hz ), if the
sw is capable of “dropping” down to the lower threshold of the au-
dible spectrum (with regard to this point, it is worth recalling the first
golden rule of sound: v=
λυ with υ=frequency and v=speed of sound,
namely about 340 m/s).
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