Certes KLEAR AUDIO KLR1m, Руководство пользователя

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subwoofers which have huge GDT (group delay time). In concert hall situation it is
usually enough to have 50ms time window. In open air situation you can freely use
wider time window if the noise and wind (look at blue curve) does not interfere and in
this case it is necessary to use windshield for microphone.
Time window is not related to distance to the loudspeaker under test.
What is “Low frequency cut” ?
Equalizer will have HPF if this function is activated. It is being applied when
measurement software creates equalizer filter and can be observed as the yellow curve
in graphs. You can set cut frequency and attenuat ion in “cut” band. But performance
of this HPF is very sharp with a high group delay introduced near a cut frequency
region. That is why it is not recommended to use it for “pro” applications.
What kind of “ignore” to apply?
It is necessary only in situation when we try to correct some disturbed measurement
curve manually. For example – ultra low noises disturbed the measurement and are
bringing measured PFR curve back to 0 dB on 20 … 30 Hz. The use of “ignore”
function will set the curve to value of the “low frequency limiter” for all range of
frequencies up to the frequency set by “ignore” parameter .
Basic workflow of APL Workshop software:
Create new measurement project by setting its folder. The first 4 symbols of project
folder name will be used for all project file
Start new measurement
– “ New ” button.
Set input and output soundcards and channels.
Give the name for measurement.
Press “ Play ” – you must hear test signal from your speaker. You must see level meter
representing microphone signal. You must avoid clipping. You do not need to keep
input level close to 0 dB FS.
Press “ Record ” and collect 80 – 150 – 250 measurement swipes (points).
Evaluate curves of your measurement. They must be reasonably smooth: