Infinity INTERLUDE IL60 - Manual (Page 2)

Stereophile Guide to Home Theater • January 2002 89
The IL60’s minimum impedance is 3.9 Ω at
230Hz; a fair rating for the nominal impedance
would be 7
Ω . (Because the impedance of most
speakers varies wildly with frequency, the nomi-
nal impedance value is always an estimate.)
The phase of the speaker’s impedance becomes
quite capacitive at 123Hz, which often indicates
a difficult load for an amplifier, particularly in
the presence of a low impedance magnitude.
But the IL60’s impedance magnitude is a com-
fortably high 10
Ω at this frequency. This, com-
bined with the powered subwoofer, should
make the speaker suitable for use with most
competent amplifiers. The IL60’s sensitivity mea-
sured about 89dB/W/m.
The pseudo-anechoic response of the IL60 at
tweeter height, averaged over a 30° forward
angle and combined with the nearfield
responses of the woofer, is shown in Fig.1
(violet). This is one of the flattest speaker
response curves we have ever measured. The
off-axis curves are also very well controlled—
another sign of a well-engineered speaker.
While the vertical response curves in Fig.2
show a good response at or slightly above the
tweeter axis, below the tweeter (an unlikely lis-
tening location for serious listening) a suckout
centered at 4kHz begins to appear. The effec-
tive bass response (–10dB) extends down to
30Hz.
The IL36 center-channel’s minimum imped-
ance of 3.3 Ω falls at 320Hz, and its sealed
cabinet is tuned to 56Hz. A reasonable nomi-
nal impedance rating would be 5
Ω . The IL36
should not be a difficult load, though the
amplifier should be comfortable driving 4
Ω .
The IL36’s sensitivity measured about
88dB/W/m.
The pseudo-anechoic response of the IL36c
at tweeter height, averaged over a 30° for-
ward angle and combined with the nearfield
response of the woofers, is shown in Fig.3
(violet). While not as strikingly flat as the IL60’s
curve, it is nevertheless a very competent result.
Just as important, the off-axis curves show little
sign of the sort of serious response dips com-
mon in horizontal center-channel speakers—
thanks to the 3-way design and its vertically
configured midrange and tweeter. The vertical
response curves in Fig.4 also show a solid
result, despite a small dip that develops below
the tweeter axis and suggests that the IL36c
should be tilted down when mounted atop a
big-screen TV. The speaker’s effective low-fre-
quency limit (–10dB) is 45Hz.—Thomas J. Norton
sitions. Male and female voices were repro-
duced (in 2-channel mode) clearly and nat-
urally: Female voices didn’t sound thick in
the lower registers, and male voices weren’t
chesty.
There’s a new JVC XRCD edition of the
Takayuki Kato Trio’s Guitar Standards, a
recent Three Blind Mice release (TBM-XR-
5041). This Japanese jazz label is known for
its good sound, and Guitar Standards,
recorded in analog on a 2-track Studer
deck, does nothing to damage that reputa-
tion. Takayuki Kato plays a Gibson acoustic
on “Estate,” accompanied by Norikatsu
Koreyasu’s powerful, sometimes bowed
bass and Shota Koyama’s dramatic percus-
sion work. The IL60s dealt with all of this
impressively, producing a credibly sized
guitar image that possessed weight, tran-
sient speed, and clarity. The cymbals,
struck or brushed, sounded properly crisp
and metallic but not hashy or edgy, and the
prominent stand-up bass was deep, power-
ful, and free of bloat. Switching out
R.A.B.O.S. resulted in a rhythmic mess, the
bass swelling and receding unnaturally. With the EQ in, proper proportion
returned, accompanied by detail and a fine
sense of depth, the percussion sometimes
sounding so far back it could have been in
the next room.
I listen to a lot of rock, and found that the
IL60 was up to that task at very high SPLs,
without strain or dynamic compression.
While bright, processed recordings sound-
ed like just that, the speaker didn’t add its
own toxic edge to the mix, and helped to
keep sonic pain to a minimum.
But good as the IL60’s performance was,
I N F I N I T Y I N T E R L U D E I L 6 0
MEASUREMENTS
Fig.1: Infinity IL60, pseudo-anechoic horizontal
response at 45° (red) and 60° (blue) relative to tweeter
axis.
Fig.2: Infinity IL60, pseudo-anechoic response at +15°
(red) and –15° (blue) relative to tweeter axis.
Fig.3: Infinity IL36c, pseudo-anechoic horizontal
response at 45° (red) and 60° (blue) relative to tweeter
axis.
Fig.4: Infinity IL36c, pseudo-anechoic response at +15°
(red) and –15° (blue) relative to tweeter axis.
All figures: Violet: pseudo-anechoic response on
tweeter axis, averaged across a 30° horizontal window,
combined with the nearfield woofer response.
woofer/line-level input, Lowpass Filter On,
R.A.B.O.S. On, and the three associated
adjustment pots. There’s also a power
switch and an IEC power jack. A front-
mounted level control for the subwoofer
glows green when a signal is present.
Five connection possibilities are outlined
in the instructions, depending on associat-
ed equipment. For home-theater use with
an A/V receiver, the LFE output is routed to
both speakers’ subwoofer line-level inputs
using a
Y connector, and the sub input is set
to Line Level.
The well-written instructions (how many
times do I get to say that?) advise you to
turn the subwoofer levels to halfway and
then listen to music. If the bass sounds
thumpy, lumpy, or boomy, R.A.B.O.S.
should be used. Otherwise, it can be
switched out. As it turned out, there was a
serious bump in my room at around 80Hz.
Using the optional Infinity-supplied
R.A.B.O.S. kit that includes a test CD, sound-
level meter, and the Q-Finder device—
which lets you correlate the Q, or width of
the resonance, to a numerical value used to
set the equalizer—I was able to identify the
frequency, width, and amplitude of the
room bump. Then, using the three poten-
tiometers, I was easily able to flatten the
bump. Infinity recommends that you then
use music to set the woofer level as you
please. The whole process took about 15
minutes. Though the IL60 is a large speaker,
I ran my pair as Small, sending everything
below 80Hz to the powered sub section
through my receiver’s Subwoofer Out jack.
Listening
Listeners accustomed to the peaky outputs
of lesser speakers might at first confuse the
IL60’s smooth, relatively flat response with
a lack of transparency, air, and detail. How-
ever, the more you listen, especially to well-
recorded music, the more you’ll come to
appreciate the IL60’s subtly impressive abil-
ities—especially if you’ve tamed a trouble-
some room bump for the first time. While
you might hear less bass than you’re used
to, there will be better, more articulate,
more tuneful bass from kick drums, and
greater timbral and textural accuracy from
acoustic and electric bass. With the excep-
tion of the lowest organ pipes, the IL60’s
low-frequency response of down to 28Hz
will deliver all the musical bass information
stored on your favorite record-
ings—and, with R.A.B.O.S., do
so without obscuring the mid-
bass and midrange.
But unlike a top-shelf sub-
woofer, the IL60 couldn’t get
down to 20Hz and below. It fell
slightly short of the best bass
with explosive sound effects
that are meant to be felt in the
stomach as well as heard, and
in its ability to convey a venue-
size-defining low-frequency
“room sound.” But consider-
ing the price, it’s almost as if
the mids and highs are thrown
in for free.
The midrange’s absence of
honky or hooty colorations
indicated effective driver tran-
I N F I N I T Y I N T E R L U D E I L 6 0
Sources
Pioneer CLD-D606 LD player
Camelot Technologies Round Table
DVD player
RCA DTC-100 HD digital tuner
Display
Philips 55PP9701 55" HD-ready RPTV
A/V Receiver
B&K AVR307
Cables
TosLink: Kimber
Speaker: Sumiko OCOS (L/C/R,
surrounds)
Video: AudioQuest S-video, component
Digital: Wireworld, Wireworld Eclipse
Gold, XLO Reference
Misc.
Audio Power Industries Power Wedge
116 line conditioner
Terk Pi indoor powered FM antenna
Terk AM Advantage AM-1000 indoor
AM antenna
REVIEW SYSTEM
88 Stereophile Guide to Home Theater • January 2002
Interlude IL36c 3-way center speaker
On the
other hand
, if you’re
musical tastes
lean toward rock, this
system
does.
Rock.
108-0201-Infin-p086-91 5/23/02 2:34 PM Page 88