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ULTRACURVE PRO DEQ2496
4. APPLICATIONS
Positions 5 and 6 are on-axis again, this time, however about
1 meter before the rear wall of the room. These measurements
will reveal any problems with reflections or stationary waves.
Please store and subsequently compare the resulting equalizer
curves. Major differences between the stored settings are most
liably caused by phase errors in the system or problems with the
room acoustics. If you cannot eliminate these problems, you
have no other choice but to find the best compromise possible. A
comparison with the stored equalizer curves will be very helpful.
Once the system has been set up as precisely as possible to
reproduce the desired transmission curve, you should walk
around in the listening area to get an impression of how the
system sounds at the various positions. Remember to make a
break between your listening tests and to use different music or
speech programs to get a feel for the systems sound and the
room acoustics.
Good equalizer settings need both time and patience! If extreme
settings are required to achieve a usable frequency response,
this should warn you of some serious problems either in the
system or the room acoustics.
Equalizers cannot solve the problems caused by poor audio
systems, but can be very useful and efficient tools for musical
fine-tuning. This, in turn, allows for often surprising improvements
in terms of acoustic transparency and the overall sound quality
of sound reinforcement systems.
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. its 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.
Fig. 4.3: Several ULTRACURVE PROs in a monitor system
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.