ClearOne RAV 600, RAV 900 Brochure & Specs

John McJunkin

Product Review

ClearOne Communications

RAV 600/900

Teleconferencing titan

Business requires sophisticated communication, and vir­tually every kind of communication technology has been
adapted and enhanced to accommodate the business
world. Teleconferencing has been practiced for decades,
and the technology that enables it has become quite so­phisticated. Until recently, however, a would-be purchaser
of teleconferencing equipment had only two options—inex­pensive lower-quality units or expensive high-end custom­installed systems. ClearOne Communications, Salt Lake
City, has fi lled the middle niche with its RAV 600/900
audioconferencing systems. These are sophisticated
systems that provide high-quality teleconferencing for a
reasonable price.

COMPONENTS

The center of the RAV (pronounced “rave”) system is the
rack-mountable audio mixer to which all other compo­nents—the mic pods, speakers, telephone lines, Ethernet,
and an RF antenna—connect. The antenna enables com­munication with a controller interface. The audio mixer also
features connections for recording, playback, external am­plifi cation, and voice tracking for the control of a motorized
PTZ video camera for videoconferencing. Two internal 15W
amplifi ers drive the speakers, and Bose 161 Articulated
Array speakers are included.

An included wireless RF controller for system operation
during teleconferences allows the call leader to control user
preferences and settings to various degrees and, most
important, to manage calls. ClearOne deliberately chose
to base this controller on a standard telephone keypad,

RAV 900 teleconferencing system

making it intuitive, regardless of a user’s technical aptitude.
Its operational range extends to 50ft. from the audio mixer,
more than enough for most applications.

The RAV system features mic pods (two with the RAV
600, three with the RAV 900). Each pod contains three
mic elements that work in concert to provide 360-degree
coverage. The pods are daisy-chained from the mixer with
Cat-5 cables terminated with RJ-45 connectors. The pods
feature a mute button and LED indicators that glow green
when the pod is active and red when muted.

The pair of Bose 161 speakers provides aural output
for the system, driven by the audio mixer’s internal 15W
amplifi ers. As with the Cat-5 for the mic pods, speaker
cabling is included.

The fi nal system component is the RAV-Ware software,
which works on Windows systems and provides advanced
system control. Although the system is intended to be
completely functional out of the box, this software enables
extended control over such things as speaker levels,
equalization, and the levels of input and output devices.
The user’s computer can interface with the audio mixer via
USB, RS-232, or remotely via LAN.

MORE THAN MEETS THE EYE

The RAV system initially appears to simply be a connected
mixer, controller, mics, and speakers. There is, however,
some pretty high science at work. First, the system uses
what ClearOne calls “adaptive modeling,” which actively
“listens” for changes in the boardroom environment. Ex­amples of such changes would be the cycling on and off of

the air conditioning system, the departure
or arrival of meeting participants, and
other signifi cant acoustical events. It also
monitors for the feedback that results
from mic-to-speaker coupling. An algorithm
based upon the ambient noise levels within
the room adjusts the processing threshold
of the adaptive modeling.

The second technology the RAV system
exhibits is acoustical echo cancellation
(AEC.) This prevents the speakers’ audio
from being picked up by the mic pods, thus
eliminating the slap-back echo that would
normally result. The three mic elements
in each pod enable the system to build
a precise model of the room’s acoustics,
enabling the system to cancel echoes.
Without getting exceedingly technical, three
distinct technologies are employed to ac­complish this—sub-band method (similar
to an FFT analysis), TX and RX correlation
(compensates for anything that acousti­cally interferes with the echo-cancellation
algorithm), and suppression techniques
(subdue residual echo resulting from
mismatches between the calculated room
model and the actual room’s acoustical
environment). There’s some pretty serious
number-crunching going on to produce a
clean, clear signal on the other end.

The third technology the RAV system
employs lies in noise cancellation. This is
essentially dynamic frequency-dependent
gating. The system analyzes the room
environment to establish what it consid­ers broadband noise and then attenuates
only the noise, allowing desired signals
to pass.

Finally, the RAV system utilizes look­ahead gating. The system determines
which of the mic elements (six in the RAV

PRODUCT SUMMARY

Company: ClearOne Communications;
www.clearone.com

Product: RAV 600/900
Pros: Ready to use right out of the box; so-

phisticated teleconferencing and noise-reduc­tion technology.
Cons: Location of RJ-45 jacks on mic pods a
little awkward.
Applications: Out-of-the-box teleconferenc­ing for users with varying levels of technical
sophistication.
Prices: $2,599 (RAV 600);
$3,099 (RAV 900)

600, nine in the RAV 900) best represents
a particular speaker’s voice. It increases
the level of that element and attenuates
the others, thus maximizing the level of
that speaker while eliminating the comb
fi ltering “swish” that normally accompa­nies multiple mics in proximity. The audio
is imperceptibly delayed, allowing the
algorithm enough time to compensate for
and eliminate the artifacts associated with
rapid gain change.

SYSTEM SETUP AND OPERATION

I found the RAV system easy to use right
out of the box. I tested a RAV 600 system,
and I was able to set it up and get it running
in about 25 minutes, including installation
of the RAV-Ware. A more professional and
permanent installation (with tidier wiring)
would take maybe another hour. My one
paltry complaint concerns the location of
the RJ-45 jacks on the mic pods, which
makes connection a bit dodgy. Otherwise,
operation is very simple using the wireless
RF controller, which can be placed near any­one seated at the conference table. The RF
controller enables only basic operations,
such as establishing and disconnecting
a call and storage of frequently called
numbers in a phonebook. The RAV-Ware
software enables much more sophisticated
control over mic pod and speaker levels,
equalization, and signal routing, along with
all the TF controller’s functions. It is even
possible to equalize the line-out signal to
optimize a recording of the conference or to
equalize the input from an external source
for inclusion in the conference.

CONCLUSION

The RAV 600/900 system is an excellent
solution for any organization that requires
high-quality teleconferencing. The quality of
the audio on both ends is very clear and
virtually noise-free, which is the fi rst reason
to consider it. The other reason I would
recommend it is the deep control availed
by the RAV-Ware software, which makes
operation simple and straightforward. The
RAV system truly does fi ll a middle-ground
niche between inexpensive speakerphones
and high-end custom systems.

John McJunkin is the principal of Avalon Audio
Services in Phoenix, which provides recording,
sound reinforcement, and forensic audio services.
He is a consultant to engineers and artists alike,
and he is employed by the Conservatory of Record­ing Arts & Sciences.

SPECIFICATIONS

Mic Pod

Frequency Response: 60Hz-14kHz (±1dB)
THD+N: <0.08% (-45dBu input at 1kHz)
Sensitivity: -45dBu
Input Level: +6dBu for 1kHz at 94dB SPL
Dynamic Range: >65dB

Line I/O

Connection: Unbalanced RCA
Gain: -10dBu nominal, adjustable from -14dB

to +18dB

Nominal Input Level: -10dBu
Nominal Output Level: -10dBu, adjustable

from -14dB to +18dB

Maximum Level: +9dBu
Impedance: >10k⍀
Output Frequency Response: 40Hz to 15kHz

(±1dB)

Output Dynamic Range: >80dB
Output THD+N: <0.02% (+6dBu input at 1kHz)

Playback/Record I/O

Connection: Unbalanced RCA
Gain: -10dBu nominal, adjustable from -14dB

to +18dB

Nominal Level: -10dBu
Maximum Level: +9dBu
Input Impedance: >10k⍀
Output Frequency Response: 40Hz to 15kHz

(±1dB)
Output THD+N: <0.02% (+6dBu input at 1kHz)

Loudspeaker

Connection: Push terminals—left/right
Power: 10W
Impedance: 8⍀
Frequency Response: 60Hz to 15kHz (±1dB)
Dynamic Range: >80dB
THD+N: <0.5% (+5dBu line input at 1kHz)
Output Level: 90dB SPL output at 1m

Mixer

AEC Tail Time: 128ms
Adaptive Noise Cancellation: (6dB to 18dB)
Gating: Adaptive ambient, fi rst mic priority,

look-ahead gating, NOM attenuation

Telephone Interface

Connection: RJ-11 (set and line jacks)
Tail Time: 30ms
Frequency Response: 250Hz to 3.3kHz (±1dB)
THD+N: <0.2% (+7dBu line input at 1kHz)
Dynamic Range: >60dB

Reprinted with permission from the February 2005 issue of

Copyright 2005, PRIMEDIA Business Magazines & Media Inc. All rights reserved.

[phone] • www.clearone.com • [e-mail]

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