Rane ECS v2 RaneWare (RaneWare 2.1) - Manual (Page 20)

RW Manual-20
SITE SURVEY
For ECS to operate properly the following must be closely
observed:
Ambient Noise Level - Air conditioning equipment (listen
for rushing air from registers and rattling air ducts), fan
noise from computer equipment, outside traffic noise, etc.
Ideal is NC 25 - NC 30 (35 to 40 dBA).
Room Absorption and reverberation time - For any
conference system to operate properly the sound reflections
must be held to a minimum. Sound reflections can be held
down by using sound absorption materials and non-parallel
walls or geometrical diffusers. Ceilings should have an
NRC (Noise Reduction Coefficient) rating of .75 to .80 and
walls should have an NRC rating of .80 to .90.
Microphone and Loudspeaker placement - It is best to use
same boundary type microphones with each microphone 4
to 6 feet apart. These microphones can reject about 12 dB
of audio from the rear. Never aim microphones directly at
any loudspeaker. It is best to place loudspeakers at the
front center of the room. Ceiling speakers can be used if
they are placed 1 foot or greater to the rear of the micro-
phone or 4 feet or greater in front of the microphone.
Angled ceiling speakers work best.
Make certain that there is adequate rack space, ventilation
and power outlets for the ECS equipment. Keep all ECS
equipment in the same rack.
Loudspeaker Audio Processing - If any processing is done,
limiters, delays, etc., between the ECB 62 Base and the
loudspeaker power amp, the ECM 82’s Echo Canceller
Reference Input must be wired to the input of the power
amp and not the Mono Output of the ECB 62 Base.
Ceiling Microphones - These microphones are typically not
recommended. If you must, the ceiling must be less than 10
feet in height and the room must have very low noise with
a high NRC rating. Never place a microphone within 4 feet
of an air conditioning register. Using techniques such as
out of phase microphones or speakers may work in some
rooms, but at best you will only gain about 6 dB of speaker
to microphone cancellation.
MultiZone Echo Cancelling (MZEC™) - By dividing the
room into zones with each zone consisting of 1 ECM 82A
mixer, improved echo canceller performance can be
achieved. Full duplex operation can be improved by
reducing the number of microphones on each mixer to 4.
Telephone Line - The telephone line should be a direct line
to the telephone company’s central office. This line should
not be shared by others, this may cause ground loops.
SYSTEM CHECKLIST
1. Know the microphone type, placement and number of
microphones.
2. Determine the operation ( Last On or Gated) of each Mic
in RaneWare. Use Last On Mics for the main participants.
Use Gated Mics for gallery areas.
3. How good are the room acoustics? Poor room acoustics
may require turning on Port 1 Suppression and/or the
Noise Gate. The Near Signal Offset and Mic Signal
Offset may need increasing.
4. Are Echo Cancellers required and how many?
5. Is telephone add-on required?
6. Is stereo audio required, and if so, which devices need
mono audio?
7. How many audio sources are there (Codecs, VCR, etc.),
and what are their audio output and input levels?
8. Is remote diagnostics required? (See the Rane RPD 1).
9. Is the system used for Multipoint? During a multipoint
conference, enable the Noise Gate with at least 6 dB of
depth.
10. Are there any non-linear devices (limiter, compressors,
etc.) between the ECB 62 Output and the amplifiers? If so,
use the output of these devices for the Echo Canceller
Reference to the ECM 82s.