Community VERIS Series - Operation and Installation Manual - Page 26
Instead of putting the two systems out-of-phase to get the sound you want, if you
attenuate the peak at crossover with any of the methods described above
2
, you are
reducing
the power that’s required to obtain a given sound pressure level. This will result
in more available power, more headroom and less demand on the drivers, all of which
lowers the potential for distortion and damage under high power conditions.
Now that you’ve chosen the final physical locations for your full-range loudspeakers and
subwoofers, established their optimum phase relationship, and brilliantly EQ’d any
crossover peaks, you’re almost ready to permanently wire the system. But first read the
section below on “Choosing the Right Loudspeakers and Electronics.”
CHOOSING THE RIGHT LOUDSPEAKERS AND
ELECTRONICS
Choose VERIS models with high enough maximum SPL to provide the needed SPL at the
farthest listener with an appropriate headroom. Typical headroom factors are at least 6 dB
for voice paging, at least 10 dB for voice reinforcement and at least 20 dB for music
reinforcement.
Choose VERIS models with the right frequency response for the application. Subwoofers
will improve the sound quality of a music reinforcement system but may reduce
intelligibility in a voice-only system in a reverberant space.
Choose VERIS models with the right coverage patterns to cover the audience evenly. Point
the loudspeakers at the listeners and away from walls and ceilings or other obstructions.
Ideally, put all loudspeakers in a central location (central cluster design) or use a
distributed system design. Minimize overlap when loudspeakers are separated by more
than approximately 40 feet.
Choose power amplifiers large enough to achieve the needed SPL in the venue with enough
headroom to avoid clipping. Use a limiter and high-pass filter to protect the loudspeakers.
Follow proper wiring design and adjust gains and levels to achieve the best signal to noise
ratio.
COMMISSIONING THE SYSTEM
Commissioning is the process of optimizing the performance of the system after it has been
installed. There are several steps in commissioning including verifying the proper operation
of each system component and adjusting system gains and levels.
The last step in system commissioning is known as system equalization or “voicing.”
Equalization is the process of adjusting the frequency response of the system to optimize
voice intelligibility or musical sound quality (or both). Note that VERIS loudspeakers are
factory voiced to optimize their speech intelligibility and musical sound quality. For this
reason, many designers find they can minimize overall system equalization and still achieve
excellent voice intelligibility and musical sound quality.
When equalizing a VERIS loudspeaker system the following points should be kept in mind to
achieve the best results and to avoid damaging the drivers.
1. Use only small amounts of equalization. In particular, do not boost frequencies by more
than about 3 dB. When cutting frequencies more than 3 dB of attenuation is acceptable.
Bear in mind that extreme frequency cuts will usually result in less than optimum
performance.
2. Do not attempt to boost any frequencies below 100 Hz with a graphic equalizer. Note
that with the recommended high-pass filter, moderate amounts of boost from a simple bass
control are acceptable.
2
The three corrective methods referred to in the text, equalizing, high-passing, and increasing the slope of the crossover, are all
various implementations of equalization.