OPER AT IO N
OPER AT ION Cont .
20
20k
16k
40
80
160 320 640 12k
Frequency (Hz)
Set at 16Hz
Set at 500 Hz
LOW SHELF SWEEP DIAGRAM
O dB
The H igh Shelf Sw eep D iagram s hows the response c urve of the High S elf filter a t
its minimum and maximum setting.
20
40k
20k
40
80
160 320 640 12k
Frequency (Hz)
HIGH SHELF SWEEP DIAGRAM
O dB
Set at 30 kHz
Set at 1 kHz
The shape is most narrow when the OCT control is set a t .3, and is widest a t the
3 setting.
100
10k 20k
6k
200
600
1k
2k
Frequency (Hz)
-20
-15
-10
- 5
5
10
15
20
50
Amplitude, 5 dB/divisio
n
Please note that when the L ow S helf is set fully countercloc kwise (16 Hz), the
filter is essentially bypassed . Simila rly, when the H igh Self control is set fully
clockwise (30 kHz), that filter is essentially bypassed.
The L evel control has a detente at the center ( 0 dB) position. if the Clip L ED is
lighting, the L evel control may be turned countercloc kwise to reduce the gain of
the RPQ160, thereb y reducing the c lipping. If a weak s ignal is present, the Le vel
control may be turned up ( clockwise) to increase the gain. To achi eve the
maximum s ignal to noise ratio, the Le vel should be set 3 dB below the c lipping
level. This is done by adjusting the Le vel control with a normal s ignal present until
the Clip L ED lights, then turning the L evel down to just below the point when the
LED goes out.
Sh own below is the typical symmetr ical response c urve of a swept parametric
band filter with the Fr equency control set a t 1 kHz, the L evel set a t +15 and -15
dB , and the O ctave control set a t .3, .5, 1, and 3 . These c urves remain consistent
over the frequency spect rum, they simply shift to whatever frequency setting is
indicated by the Fr equency control.
The two shelving filters are designed to roll off the frequency response of the
Signal; the Low Shelf cuts the frequencies 3 dB at the control ’s indicated setting
and rolls off below, and the H igh Shelf cuts the frequencies 3 dB at the indicated
setting and rolls of above. The L ow S helf Sw eep D iagram s hows the response
curve of the L ow S elf filter a t its minimum and maxi mum setting.
APPLIC AT IONS
The RPQ160 ’s precise equalization has many applications including school or
church gymnasium s, home or professional recording s tudios, live sound, or
musical instruments.
When coupled with a spect rum analyz er, the RPQ160 can match exactly the
properties of typical acoustic resonances and reflections , and make immediate
improvements to a ny installed system ’s a mplitude and phase respons e.
Live applications include equalizing trouble spots where a mix may be muddy, too
harsh, flat, and eve n eliminate feedba ck precisely without a ffecting the flavor of
the overall sound.
Recording s tudios benefit from the RPQ160 ’s precise equalization in notching out
trouble frequencies that need to be removed, or by re-equalizing a final mix .
