REL Acoustics No. 25, Руководство по эксплуатации

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No.25 employs an advanced filter circuit which provides exceptional performance when coupled to the rest
of the signal chain of the Sub-Bass System. A second-order variable low-pass filter approximating a Bessel
function was chosen for its linear phase response, which equates to flat group delay. This means that, unlike
other filter functions, the amount of delay the signal is subjected to during processing is constant through
the entire pass-band, which improves the frequency response and allows for better integration of the sub
with the main speakers. An additional fixed second-order Bessel filter follows the variable filter, removing
unwanted midrange signals that, if left unfiltered, cause the midrange of the main speakers to become
muddy or congested. All filtering is performed in the analog domain using high-quality components with
tight tolerances to ensure the highest possible performance and consistency.
The amplifier is inherently stable and will retain its characteristics over very long periods of time – important
in a unit designed for an exceptionally long working life. These amplifiers are designed to withstand reasonable
abuse and overloads. If in doubt, please contact your dealer.
We believe that the importance of the electronics, cabinet and drivers being designed to work in harmony is
paramount. This belief allows No.25 to achieve the highest possible level of fidelity.
Overload Protection
All REL Sub-Bass Systems are designed as true sub bass speakers. They are designed to reproduce those
exceptionally deep notes that are felt as well as heard. This it will attempt to do at whatever volume level
you set. If set too high no damage should result because the built-in electronics will limit the cone movement.
This electronic control is called Set-Safe™. It constantly and instantaneously monitors the output from the
power amplifier and is totally transparent in operation until required. This means it has absolutely no effect
on the sound quality of your REL until an overload is detected.
Ordinarily an overload would cause the power amplifier to go into clipping with resultant loss of control
over the drive unit. This can cause drive unit damage, and always sounds nasty. Set-Safe™ detects the point
of incipient clipping and gently soft-clips the waveform of the signal to ensure actual clipping does not occur.
This is a necessarily simplified description of what actually happens, but in effect, Set-Safe™ controls the
amplifier and ensures there is minimum risk of amplifier and driver damage caused by over-driving.
Technical