T221M
Biampable, Compact,
Two-Way Floor Monitor
Speaker System
• Constant-directivity 80° x 55° horn
with 2-inch titanium driver
• High-output, 400-watt, 12-inch woofer
• Biamped or full-range operationsimple biamp instructions included
inside the enclosure
• Rock-solid enclosure made with
12-ply curved plywood shell
• PROTM circuit provides HF driver
protection
• Professional Neutrik Speakon
connectors for biamp or full-range
operation
®
Description
The Electro-V oice T221M is a 400-watt, twoway, high-efficiency floor monitor system. It
combines professional-quality components,
highlighted by the DH2T compression driver
and 400-watt, high-output 12-inch woofer.
The system may be biamplified or used full
range with the internal passive crossover.
Either way, the result is clear and articulate,
high-quality sound.
The enclosure is constructed of a void-free
3/4-in. 12-ply curved plywood shell which
is extremely rigid. The baffle and end pieces
are made from 13-ply birch plywood. This
high-strength enclosure is sprayed with a
resilient, textured black finish for a truly professional appearance. The end-mounted,
heavy-duty, recessed handle makes transportation easy and three rubber feet on the
opposite end help keep the finish looking
new.
The high-frequency section of the T221M
utilizes a compact 80° x 55° constant-directivity horn driven by a wide-bandwidth, twoinch-titanium-diaphragm driver. The voice
coil is coupled to the diaphragm with EV’s
exclusive Resonant Drive
increases and smooths the high-frequency
TM
technology. This
response and reduces the amount of internal
equalization required for flat frequency response.
EV’s self-resetting PRO
the crossover network to guard the compression driver from damage. If input power to
the driver exceeds the nominal rating, the
TM
PRO
circuit is activated, reducing the
power delivered to the driver by 6 dB. The
system will remain in this mode of operation until input power is reduced to a safe
level.
The optimally vented bass section of the
T221M is designed using Thiele-Small parameters for efficient performance to below
100 Hz. The high-output 12-inch woofer
delivers outstanding performance. It features
beryllium copper lead wires with a low-mass,
edge-wound voice coil and high-temperature
materials. The coil is driven by a massive,
15-lb magnetic structure.
Frequency Response
The combination of a 12-inch woofer, DH2T
wide-bandwidth high-frequency driver and an
equalized crossover results in the wide and
smooth overall response shown in Figure 2.
The T221M’s axial frequency response was
measured in Electro-Voice’s large anechoic
TM
circuit is built into
chamber at a distance of 10 feet with a swept
sine-wave input of 4 volts. Figure 2 has been
averaged and corrected for 1 watt/1 meter,
half-space operation.
Directivity
The polar response of the T221M speaker
system at selected one-third-octave bandwidths is shown in Figure 1. These polar
responses were measured in an anechoic
environment at 20 feet using one-third-octave pink-noise inputs. The frequencies
selected are fully representative of the polar
response of the system. Beamwidth of the
system utilizing the complete one-third-octave polar data is shown in Figure 1. R
directivity index (D
Biamping
The T221M may be easily converted for
biamp operation. To do this, first carefully
remove the crossover. Notice the instructions on the circuit board and the four-wire
“Molex” connector. The T221M comes from
the factory in passive (full-range) mode. T o
convert the T221M to biamp operation, unplug the “Molex” connector from the header
marked “PASSIVE MODE (FULL
RANGE”) and plug it into the header labeled
) are plotted in Figure 4.
i
and
θ
T221M Biampable, Compact, Two-Way Floor Monitor Speaker System
“BIAMP”. The crossover is now in biamp
mode. Carefully replace the crossover and
screws. When the crossover is in biamp
mode, there is an 18-microfarad capacitor
in series with the high-frequency driver for
protection against DC voltages or amplifier
failure. This is not a crossover. It is however, protection against some forms of amplifier failure. An active crossover with a
crossover frequency of 1,600 Hz (1.6 kHz)
with slopes of 12 dB per octave or greater is
required. Whenever possible, a crossover
with 24-dB-per-octave slopes should be
used.
Note: The PRO
TM
circuit is still protecting
the high-frequency driver when the system
is in biamp mode.
Power-Handling Capacity
To our knowledge, Electro-Voice was the
first U.S. manufacturer to develop and publish a power test closely related to real-life
conditions. First, we use a random-noise input signal because it contains many frequencies simultaneously, just like real voice or
instrument program. Second, our signal contains more energy at extremely high and low
frequencies than typical actual program, adding an extra measure of reliability. Third, the
test signal includes not only the overall
“long-term average” or “continuous” level—
which our ears interpret as loudness—but
also short-duration peaks which are many
times higher than the average, just like actual program. The long-term average level
Connections
The T221M is equipped with Neutrik
Speakon
®
NL4MPR connectors. Two connectors are installed in parallel, one mounted
on each end of the enclosure allowing
multiple T221M’s to be used and “daisychained” together. These NL4FC connectors
are used because they are locking, self-polarizing and capable of 30 amps rms continuously.
Full-range pin arrangements are:
1– = IN, FULL RANGE(–)
T221M Biampable, Compact, Two-Way Floor Monitor Speaker System
1+ = IN, FULL RANGE(+)
2– = Not used
2+ = Not used
Biamp pin arrangements are:
1– = IN, LOW FREQUENCY (–)
1+ = IN, LOW FREQUENCY (+)
2– = IN, HIGH FREQUENCY (–)
2+ = IN, HIGH FREQUENCY (+)
If you experience any difficulty in obtaining cables, connectors or wiring accessories,
the following companies can be contacted:
Neutrik USA, Inc.
1600 Malone Street
Millville, NJ 08332
Pro Co Sound, Inc.
135 E. Kalamazoo Avenue
Kalamazoo, MI 49007
Whirlwind Music Distributors, Inc.
P.O. Box 1075
Rochester, NY 14603
stresses the speaker thermally (heat). The
instantaneous peaks test mechanical reliability (cone and diaphragm excursion). Note
that the sine-wave test signals sometimes
used have a much less demanding peak value
relative to their average level. In actual use,
long-term average levels exist from several
seconds on up, but we apply the long-term
average for several hours, adding another
extra measure of reliability.
Specifically, the T221M is designed to withstand the power test described in EIA Standard RS-426A. The EIA test spectrum is
applied for eight hours. To obtain the spectrum, the output of a white-noise generator
(white noise is a particular type of random
noise with equal energy per bandwidth in Hz)
is fed to a shaping filter with 6-dB-per-octave slopes below 40 Hz and above 318 Hz.
When measured with an analyzer having the
usual constant-percentage bandwidth (onethird octave), this shaping filter produces
a spectrum whose 3-dB-down points are
at 100 Hz and 1,200 Hz with a 3-dB-peroctave slope above 1,200 Hz. This shaped
signal is sent to the power amplifier with the
continuous power set at 400 watts into the
5.98-ohm EIA equivalent impedance
(48.9 volts true rms). Amplifier clipping
sets instantaneous peaks at 6 dB above the
continuous power, or 1,600-watts peak
(97.8 volts peak). This procedure provides a
rigorous test of both thermal and mechanical failure modes.
Architects' and Engineers'
Specifications
The loudspeaker system shall be a two-way,
full-range design consisting of a 305-mm
(12-inch) woofer in a vented enclosure, a
high-frequency compression driver mounted
on a 80° x 55° constant-directivity horn, and
a passive crossover/equalizer network, which
may be bypassed for use with an external
low-level active dividing network with a
corner frequency of 1,600 Hz. The loudspeaker shall meet the following performance criteria: frequency response of
100-16,000 Hz, –3 dB; full-range power
handling of 400 watts long term and 1,600watts short term with a shaped random-noise
input per EIA Standard RS-426A; low-frequency power handling below 1,600 Hz in
the biamp mode of 400-watts long term and
1,600-watts short term with a shaped random-noise input per EIA Standard RS-426A;
high-frequency power handling above
1,600 Hz in the biamp mode of 60-watts
long term and 240-watts short term with a
shaped random-noise input per EIA Standard
RS-426A; sensitivity of 101 dB SPL at 1 meter
with a 1-watt, 300- to 3,000-Hz pink-noise
input; 6-dB-down horizontal coverage angle
of 55° ±5° in the 5,000- to 16,000-Hz range;
6-dB-down vertical coverage angle of 80°
±5° in the 5,000- to 16,000-Hz range; crossover frequency of 2,600 Hz (electrical);
nominal impedance of 8 ohms; and minimum impedance of 6.7 ohms. Input connections shall be two paralleled Neutrik
Speakon
®
NL4MPR connectors for fullrange and biamp operation. The enclosure
shall be constructed of curved plywood,
covered with black textured paint and fitted with a 16-gauge black steel grille, rubber feet and a recessed carrying handle. Dimensions shall be 371 mm (14.62 in.) high x
594 mm (23.4 in.) wide x 406 mm (16.0 in.)
deep. Net weight shall be 22.3 kg (49 lb).
The loudspeaker system shall be the ElectroVoice T221M.