Behringer DEQ2496 Manual - Page 16

16 ULTRACURVE PRO DEQ2496 User Manual 4.2 Equalizer in the monitor path The use of the ULTRACURVE PRO in the monitor path follows the same basic rules as the sum-signal equalizer application described above. Additionally, the DEQ2496 offers a few features that are particularly useful for monitoring purposes. The Feedback Destroyer helps you identify and eliminate feedback frequencies during sound check. Once a specific feedback frequency has been found, it can be eliminated by assigning the corresponding filter to it in SNGL mode. If hand-held (i.e. wireless) microphones are used, the acoustic conditions will be changing all the time. In this case, it is useful to set the Feedback Destroyer filters to automatic search mode (AUTO). The Feedback Destroyer is suited only for those signal paths that carry heavily modulated signals only (speech, vocals, drums). In principle, there is no way to distinguish long-sustaining sine tones produced for example by a synthesizer or flute from feedback. Here, the result would be the unwanted elimination of such sounds. If all automatic filters are already in use suppressing feedback, and a new feedback frequency is found, the first filter used will be released and set to the new frequency. The Feedback Destroyer can work no miracles, but it can increase the feedback immunity of the audio system by a few dBs. Whenever it responds, you should consider this a warning to reduce the volume level on stage. Basically, the on-stage volume level should be kept as low as possible, because: 1. it will be easier on your hearing, 2. there are less feedback problems, and 3. it's easier to achieve a good P.A. sound. Often, the volume of the monitor speakers is raised as a concert goes on. Use breaks and pauses to reduce all monitor paths by about 3 dB. The musicians will not or hardly hear that the volume has been reduced, because during a break their hearing can relax a bit. This gives you valuable headroom in your system. If you use certain speaker types on a regular basis, you can save standard settings on your equalizer, which have proven useful in practice (e.g. for 15" wedge or drum-fill speakers). Extremely low frequencies are usually faded out completely to avoid a "muddy" sound on stage caused by low-frequency feedback. Figure 4.3 shows an example of using several ULTRACURVE PROs in a 8-way monitor system. The AFL output of the monitor console (usually feeding the control speaker at the monitor console) can alternatively be connected via the RTA/MIC input. On the DEQ2496, select the RTA input in the RTA menu to display the signal of the currently active monitor path. 4.3 Using the ULTRACURVE PRO in the studio The number of possible uses for your DEQ2496 in a studio environment is endless. Your imagination is the only limit. Here are just a few examples: As an equalizer for the monitor speakers: apart from the usual graphic equalization (GEQ) the parametric filters (PEQ) can be used efficiently to suppress narrow-band room resonance. What is more, the DEQ2496 functions as an A/D and D/A converter for the conversion of analog to digital, and vice versa. As a mastering equalizer: Owing to the stereo link function all settings on the graphic equalizer must be made only once. Here, too, the additional parametric filters can be used effectively for fine-dosed equalization. Use the AES/EBU inputs/outputs (optional) for sound processing purely in the digital domain. For general sound shaping: The option to change programs via MIDI and modify all parameters via MIDI controllers makes the ULTRACURVE PRO a particularly flexible tool if combined with a MIDI sequencer. For example, this allows you to change settings during mix-down and still have them reproducible all the time. 4.4 Using the ULTRACURVE PRO as a delay unit Apart from the applications described in chapter 4.1, it also happens that speaker stacks must be set up at a larger distance from the stage to produce some direct radiation at remote positions. In order to make up for the run-time differences between the on-stage speakers and the remote stacks, the latter must be provided with an electronically delayed signal. Usually, special delay lines are used for this, however, not so with the DEQ2496, because it already includes a signal-delay option. This function can be operated as conveniently as on any dedicated device. The delay setting is stored with a program, and by using the MAIN and AUX outputs you need only one DEQ2496 to set up a delay line: simply delay one of the output signals and send it to the remote speaker stacks. Outputs 1 to 8 Stereo output L + R AFL Output RTA Input Fig. 4.3: Several ULTRACURVE PROs in a monitor system Monitoring mixing console XENYX 2222FX Side ll L Side ll R Side ll Drums Keyboard Fill Wedge 1 Wedge 2 Wedge 3 Wedge 4 ULTRACURVE PRO DEQ2496 Aux output L + R (Delay Line) Main output L + R Fig. 4.4: Run-time correction in a sound reinforcement system using the ULTRACURVE PRO