Of course, you can use the FINE button to fine tune to frequencies between the standard ISO frequencies (in
Hz | 20 | 25 | 31,5 | 40 | 50 | 63 | 80 | 100 | 125 | 160 | 200 | 250 | 315 | 400 | 500 | 630 | 800 |
kHz | 1 | 1,25 | 1,6 | 2 | 2,5 | 3,15 | 4 | 5 | 6,3 | 8 | 10 | 12,5 | 16 | 20 |
|
|
|
Tab. 4.2: standard ISO frequencies
4.3 Parametric equalizers
Parametric equalizers, unlike graphic EQ’s, allow for selecting both the processing frequency and the band- width, so that it is possible to process any given signal in full detail. Naturally, this equalizer design can also be used to “filter” unwanted signals, however, only if these signal have a fixed frequency. If the frequency changes, the parametric equalizer would have to be readjusted all the time. The majority of (analog) parametric EQ’s suffers from a quite fundamental drawback: they are operated by means of rotary controls, i.e. contrary to graphic EQ’s, it is much more difficult to make necessary readjustments quickly.
4.4 The FEEDBACK DESTROYER PRO
As you have seen, suppressing feedback with a standard graphic and/or parametric equalizer often means that you have to accept compromises. Since feedback signals fail to comply with the standard ISO frequencies of graphic EQ’s and additionally can have changing frequencies, their suppression with a graphic equalizer is more or less a matter of luck.
Example: let’s assume a feedback signal at 1.8 kHz is produced during a concert. To suppress it, you’ve got to cut the 1.8 kHz band on your EQ. However, since graphic equalizers only have 1.6 and 2 kHz bands, you might need to attenuate both bands. Result: although feedback will be eliminated due to the low filter quality, you will also fade out many music signals which you’d actually wish to keep. Additionally, cutting these midrange frequencies also means that your P.A. system loses power and performance.
In theory, a parametric EQ can be used to suppress feedback by means of high filter qualities. However, your tweeters may well have gone up in smoke before you’ve found the frequency at which feedback occurs and managed to eliminate it by adjusting the filter frequency, bandwidth and gain accordingly. For this reason, the FEEDBACK DESTROYER PRO also uses a highly optimized version of the automated, fully parametric filters we designed for the BEHRINGER
Unlike many conventional equalizers, the FEEDBACK DESTROYER PRO provides an impressive range of features:
sIf required, the FEEDBACK DESTROYER PRO detects and suppresses feedback automatically by ana- lyzing the music signal and determining the frequency of the interference signal. Additionally, it calculates the filter quality and attenuation necessary to fade out feedback.
sThe FEEDBACK DESTROYER PRO calculates the filter quality with such a high precision that nothing but the feedback signal will be filtered, while retaining the original music signal. This means increased P.A. headroom and a more balanced, powerful and transparent sound image.
sWith the FEEDBACK DESTROYER PRO almost all of the power delivered by the amps will reach the speakers, because the precisely set,
sThe filters can be operated both in manual and automatic mode. Naturally, you can combine both modes in single programs.
sClearly structured entry keys give you direct access to essential parameters, while the jog wheel allows you to conveniently adjust them as desired. Favorite settings can be stored in 10 preset programs. Of course, the FEEDBACK DESTROYER PRO fully integrates into any MIDI system.
sThis enormous processing power is provided by a
4. TECHNICAL BACKGROUND | 23 |
E