Certes KLEAR AUDIO KLR1m, User Manual

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You can reestablish any balance you like by C1 parametric EQ or by a target curve
application in APL Workshop software, in the field “Targets, Corrections”. (Examples:
mp1.txt, 1dBperOCT.txt, 7dB_krit_INTPc.txt).
Directivity of loudspeaker
There is a problem of APL correction application on loudspeakers with particularly
strong directivity. Those problems are notable in HF range and earlier it was advised to
correct this by usage of parametric EQ but there is also a solution based on
measurement.
Loudspeaker has directivity properties in all frequencies when the size of its emitting
surface becomes commensurate with
wavelength . It is fair for all concert equipment
and especially line arrays as well as for “home” loudspeaker with, for example 6,5” cone,
showed directivity right away in MF and HF as well.
And so, actions:
1. Measure PFR (Power Frequency Response, green curve in APL Workshop graphs,
(
*_PR.dat file ) of a loudspeaker. If loudspeaker surroundin g is “strange” (hard to
define reflecting surfaces), place it in a middle of room on the floor, and measure
it at minimal distance commensurate to its size. For concert hall, measure in
minimal admissible distance, but of course leaving loudspeaker at his working
placement.
2. In this Subordinate measurement we should separate (allocate) directivity
effects from the overall PFR curve. For that you should subtract earlier
acquired PFR from this Subordinate curve like using correction. You must set
early measured PFR curve (
*_PR.dat file ) as correction for this currant,
Subordinate measurement and recalculate it by pressing “ Calculate ” button
(using *_PR.DAT PFR measurement file). Acquired curve shows just
directivity. LF part of it is usually highly disturbed by wave interference and
therefore you must use LF part with care . Usually, it can’t be used lower than 1
kHz as it is, but higher than 1 kHz, with 1 octave smoothing turned on. You
can use this curve to introduce compensation of directivity by adding this
curve to original PFR such way
– 1) set “ ignore curve ” to 1 kHz, for example,
and “low frequency limiter” to 0 dB (that sets curve to 0 from LF to 1kHz), set