Specifications

mented controls—including full bass man-
agement. The latter is exceptionally flexible,
as long as the source is Digital or Analog-
DSP. (With Analog-Direct, only volume,
individual speaker level, balance, and mute
still function.) While you can’t change the
crossover slopes (24dB for lowpass, 12dB for
highpass), the crossover frequency—both
highpass and lowpass—can be varied from
40Hz to160Hz, and the maximum bass level
can be set using the Bass Peak Level Manag-
er, which “looks ahead” at the bass signal in
the LFE channel, reducing the bass signal if
it’s about to exceed the predetermined max-
imum level. Engaging the AVM 20’s Super
subwoofer mode copies the bass to the sub-
woofer(s) even if the other speakers are des-
ignated Large. This can come in handy
when listening to stereo source material
with a lot of bass content.
Analog-DSP also features a very quiet
(100dB) digital recording output (selectable
16-bit/44.1kHz or 24/88.2) that can be used
with a computer CD burner, thus bypassing
the noisy (typically about 70dB) A/D con-
verter used by most soundcards. This pro-
vides for higher-quality CD-R recordings
with external phono stages, tape decks, or
the AVM 20’s tuner.
A feature I haven’t encountered in any
other surround pre-pro is Center EQ, which
modifies the frequency response of the
center speaker to compensate for the effect
of the speaker being placed on top of a TV
set or installed in a wall unit. According to
testing by Sonic Frontiers, placing a speak-
er atop a TV typically produces a bump at
1kHz and a suckout at 300Hz. Center EQ
introduces reverse EQ (varied to take into
account the size of the TV), producing a
flattening of the frequency response. The
effect should be greater clarity of center-
channel dialogue. However, in true audio-
phile fashion, Sonic Frontiers advises that,
“in some situations, leaving the Center EQ
off completely may sound better. Let your
ears be the final judge!” I don’t have my
center-channel speaker on top of a TV, so I
had no need of Center EQ, but it could pro-
vide the ideal tweak in some systems.
Yet another potentially useful feature is
Audio Group Delay. Not to be confused with
the delay settings for center and surround
speakers, this feature delays all audio in
relation to video. Many video processors—
doublers, quadruplers, scalers—cause
video to be delayed, and unless the sound is
delayed correspondingly you’ll end up with
it not being synchronized with video. This is
particularly annoying for dialogue or
singing, with the sound of the person’s voice
arriving before you see their lips move. The
AVM 20 allows Audio Group Delay of up to
85ms, the delay being source-specific, the
exact amount determined by checking the
manual for the video processor—and, of
course, by watching and listening.
The AVM 20’s surround modes include
the usual Dolby Pro Logic, Dolby Digital,
and DTS, with optional THX Cinema and, if
the system has 7.1 channels, THX Surround
EX. (THX Surround EX adds decorrelated
rear-channel information to the Re-Equal-
ization, Timbre Matching, and Adaptive
Surround Decorrelation that are part of THX
Cinema.) The AVM 20 also has a proprietary
surround mode called Cinema Logic,
intended for 2-channel material, and a few
DSP modes for simulated acoustical venues
(Theater, Stadium, Club, Church, Hall). All
Channel Stereo and All Channel Mono are
intended mainly for party purposes.
The design of the AVM 20’s surround pro-
cessing and digital control functions is built
around the Motorola Digital DNA 56366
chip, in Sonic Frontiers’ own two-pcb DSP
implementation. The D/A converters are
24/192 AKM AK4382s; A/D converters are
24/96 AKM AK5383s. The volume control is
a Crystal CS3310, used in a number of high-
end preamplifiers. There are 10 regulated
power-supply stages.
Until fairly recently, the possible degrada-
tion of video quality by video switchers and
onscreen display (OSD) circuits has been
given little attention by the makers of sur-
round pre-pros. As video displays improve
in resolution and the DVD format (often
using component-video connections) and
SONIC FRONTIERS ANTHEM AVM 20 & ANTHEM PVA 7
Stereophile Guide to Home Theater