Infinity IL60 User Manual
EQUIPMENT REPORT
SURROUND SPEAKER SYSTEM
Infinity
Interlude IL60
INFINITY INTERLUDE IL60
Michael Fremer
Big is beautiful. The Infinity
Interlude IL60 is big but not superficially
beautiful. What’s beautiful is that a big
company like Harman International can
spend millions on driver-technology R&D,
build a state-of-the-art speaker like the
$10,000 Infinity Prelude MTS—a bargain
itself—and then shower the considerable
R&D benefits on a modestly priced speaker
like the IL60. At $2000/pair, it can hardly be
described as a “poor man’s” Infinity Prelude, but considering what you get for your
money, the IL60 is one of the best loudspeaker values around.
SPECIFICATIONS
Interlude IL60 4-way floorstanding tower
speaker with powered subwoofer
Drivers: 1" dome tweeter, 4" midrange cone,
1
⁄
2
" midbass cone, 12" powered subwoofer
6
cone
Subwoofer amplifier: 500W into 8Ω
Frequency response: 28Hz–22kHz, ±3dB
(subwoofer: 20–100Hz, <0.1% THD)
Nominal impedance: 8Ω
Sensitivity: 89dB (2.83V @ 1m)
Recommended amplification: 15–175W
Dimensions: 48" × 9
Weight: 75 lbs
Price: $2000/pair
Interlude IL36c 3-way center speaker
1
⁄4" × 171⁄4" (H×W×D)
The floorstanding 4-way tower includes a
1-inch dome tweeter, a 4-inch midrange, a
1
6
⁄2
-inch midbass driver, and a side-mounted 12-inch woofer powered by a built-in
500W amplifier. The drivers, as in every
Interlude speaker, are all Ceramic Metal
Matrix Diaphragms—aluminum coated on
both sides with a ceramic material—
designed under the watchful eye of Dr.
Floyd E. Toole, Harman’s vice president of
engineering, who spent years researching
loudspeakers at Canada’s National
Research Council in Ottawa. These stiff,
lightweight, low-resonance drivers are
Drivers: 1" dome tweeter, 4" midrange cone,
1
⁄
2
" cone woofers
two 6
Frequency response: 55Hz–22kHz, ±3dB
Nominal impedance: 8Ω
Sensitivity: 91dB (2.83V @ 1m)
Recommended amplification: 15–175W
Dimensions: 23" × 9" × 12
Weight:32 lbs
Price: $500
Interlude IL10 2-way surround speaker
Drivers: 1" dome tweeter, 6
Frequency response: 56Hz–22kHz, ±3dB
Nominal impedance: 8Ω
Sensitivity: 88dB (2.83V @ 1m)
Recommended amplification: 15–150W
1
⁄
2
" (W×H×D)
1
⁄2" cone woofer
designed to have uniform dispersive characteristics so that direct and reflected
sounds maintain similar, smooth timbral
balances. Toole’s research has shown that
the ear is particularly sensitive to resonant
peaks, whether they’re heard from on- or
off-axis. Generally, the higher the Q of the
resonance (that is, the narrow er in fr equency width), the greater its amplitude must be
for us to hear it. Toole’s research demonstrates that we can perceive low-Q resonances (ones that cover a wider frequency
range) that deviate as little as 1.5dB from
flat-on orchestral material and 0.3dB on
5
1
⁄
2
" × 11
1
⁄
2
" (H×W×D)
⁄
Dimensions: 15
Weight:18 lbs
Price: $400/pair
System
Drivers: all C.M.M.D. (Ceramic Metal Matrix
Diaphragm)
Price: $2900
Manufacturer
Infinity Systems
250 Crossways Park Drive
Woodbury, NY 11797
tel. (800) 553-3332
fax (516) 682-3523
www.infinitysystems.com
8
" × 8
pink noise.
The IL60 also includes the ingenious
R.A.B.O.S. (Room Adaptive Bass Optimization System), a user-friendly, single-band
parametric bass-equalization scheme to
deal with the low-frequency “bumps” that
afflict most rooms. With only two speakers,
it’s possible to minimize the problem with
speaker placement. But home-theater
speaker placement is often dictated by
where you put your monitor, making
R.A.B.O.S. an even more important feature
for a 5.1-channel setup.
Where did Infinity cut costs to bring the
IL60’s price down to $2000/pair? Rap the
side of the cabinet and you’ll know. Or look
at it closely: The overall construction quality—fit, finish, and bracing—is competent,
but not in the same league as far more
expensive speakers. Nonetheless, the IL60
PHOTOS © 2002 CORDERO STUDIOS
is an amazing value that few small companies could afford to offer. And with a choice
of three grillecloth colors (Warm Platinum
is standard), it can be dressed up to look a
bit less monolithic. (A smaller, less expensive 3-way system, the IL50, $1298/pair, is
also available.)
At 32 lbs, the four-driver, 3-way Interlude
IL36c is one of the heftier center-channel
speakers around. It costs $500 and has a 1inch dome tweeter and a 4-inch midrange,
these flanked by a pair of 6
vers. It’s 23 inches wide and 12
deep, so before you buy, make sure your
monitor can accommodate it. (The smaller,
lighter, three-driver IL25c is also available,
for $299.)
Infinity also sent along a pair of Interlude
IL10s ($400/pair), one of the smaller models
in the Interlude line, for use as surrounds.
1
⁄
2-inch bass dri-
1
⁄
2 inches
The IL10 is a stand-mounted 2-way featuring a 1-inch tweeter and a 6
As reviewed, the complete system cost
was $3950—a solid value. But just before
press time, Infinity reduced the cost of the
IL60 to $2000/pair (from $3000) and the
IL10 to $400/pair (from $450). That drops
the cost of the entire system to $2900—a
steal, particularly when you realize that that
includes a center-channel speaker that’s
not the usual top-of-the-TV afterthought,
and 1000W of dual 12-inch bass power;
unless you really feel the need to go below
28Hz (and I do mean feel), you won’t need a
subwoofer .
Setup
The IL60’s rear panel includes subwoofer
line-level in and out, a set of speaker-level
5-way binding posts, and switches for sub-
1
⁄
2-inch woofer.
86 Stereophile Guide to Home Theater • January 2002
Stereophile Guide to Home Theater • January 2002
87
INFINITY INTERLUDE IL60
INFINITY INTERLUDE IL60
On the
does.
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 frontmounted level control for the subwoofer
glows green when a signal is present.
Five connection possibilities are outlined
in the instructions, depending on associated equipment. For home-theater use with
an A/V receiver, the LFE output is routed to
both speakers’ subwoofer line-level inputs
using a Yconnector , 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 , soundlevel 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
other hand
Rock.
, if you’re
Interlude IL36c 3-way center speaker
musical tastes
room bump. Then, using the three potentiometers, 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. However, the more y ou listen, especially to wellrecorded music, the more you’ll come to
appreciate the IL60’s subtly impressive abilities—especially if you’ve tamed a troublesome 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 exception of the lowest organ pipes, the IL60’s
low-frequency response of down to 28Hz
will deliver all the musical bass information
lean toward rock, this
stored on your favorite recordings—and, with R.A.B.O.S., do
so without obscuring the midbass and midrange.
But unlike a top-shelf subwoofer, 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 venuesize-defining low-frequency
“room sound.” But considering 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-
system
REVIEW SYSTEM
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
sitions. Male and female voices were reproduced (in 2-channel mode) clearly and naturally: 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 reputation. Takayuki Kato plays a Gibson acoustic
MEASUREMENTS
The IL60’s minimum impedance is 3.9Ω at
230Hz; a fair rating for the nominal impedance
would be 7Ω. (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 10Ω 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 ver y 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 listening location for serious listening) a suckout
centered at 4kHz begins to appear. The ef fective bass response (–10dB) extends down to
30Hz.
The IL36 center-channel’s minimum impedance of 3.3Ω falls at 320Hz, and its sealed
cabinet is tuned to 56Hz. A reasonable nominal impedance rating would be 5Ω. The IL36
should not be a difficult load, though the
amplifier should be comfortable driving 4Ω.
The IL36’s sensitivity measured about
88dB/W/m.
The pseudo-anechoic response of the IL36c
on “Estate,” accompanied by Norikatsu
Koreyasu’s powerful, sometimes bowed
bass and Shota Koyama’s dramatic percussion work. The IL60s dealt with all of this
impressively, producing a credibly sized
guitar image that possessed weight, transient 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, pow erful, and free of bloat. Switching out
R.A.B.O.S. resulted in a rhythmic mess, the
bass swelling and receding unnaturally.
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.
at tweeter height, averaged over a 30° forward 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 ver y competent result.
Just as important, the off-axis curves show little
sign of the sort of serious response dips common in horizontal center-channel speakers—
thanks to the 3-way design and its vertically
configured midrange and tweeter. The ver tical
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 sounded 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,
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.
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-frequency limit (–10dB) is 45Hz.—Thomas J. Norton
88 Stereophile Guide to Home Theater • January 2002
Stereophile Guide to Home Theater • January 2002 89
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