Electro-Voice TL880P User Information

Description and Applications
The Electro-Voice TL880P is a member of
the TL series of low-frequency enclosures.
The TL880P is a powered subwoofer de-
signed expressly for digital sound on film
and other applications which require very
high low-frequency pumping ability ex-
tending to 25 Hz and below. The TL880P
features an Electra-Voice P1250 power am-
plifier, set up in bridge mode driving two
(1
EVX-180A 457-mm 8-in.) speakers, with
a combined rating of 2,000 watts continu-
ous program, connected in parallel. The
P1250 can deliver 1.200 watts continuous
(20-20,000 Hz) to the resultant 4-ohm load.
The P1250 has on-board signal processing
which supplies:
1. Low-frequency equalization nec-
essary for "step-down" operation
of the loudspeaker system, pro-
viding an overall system response
whose 3-dB-down point (f,) is 23 Hz.
2 . I n f r a s o n i c p r o t e c t i o n o f t h e
EVX- 180A-s below the P1250' s
peak boost frequency of 26 Hz.
3. Output limiting that prevents ampli-
fier clipping under high-output con-
ditions.
The side-mounted input for the amplifier
facilitates behind-the-screen installation,
where limited space between the screen and
theatre wall often makes it difficult to con-
nect to the back of an enclosure.
In addition to motion-picture applications, the
TL880P is highly appropriate as the subwoofer
in large, multiway systems for contemporary
music playback and sound reinforcement. The
TL88OP has more output below 40 Hz than the
devices typically used in these applications, in
either the normal (25 Hz) or alternative
(30 Hz) box tuning (see Alternative Vent Tun-
ing and Equalization Options section). Thus.
the TL880P is not only appropriate for the
more typical 40-Hz-and-above subwoofer re-
quirements, but also for those applications,
e.g., very-low-frequency synthesized effects
and down-tuned bass guitars, that require high
output below 40 Hz. This extended low-fre-
quency performance also plumbs the depths
of the symphony orchestra and pipe organ.
Frequency Response
The TL88OP's axial frequency response was
measured in Electro-Voice's large anechoic cham-
ber at a distance of 3.05 meters (10 feet) with a
swept sine-wave input. Figure 1
aged and corrected for 1 watt/l meter into the
transducers.
TL880P
Very-Low-Frequency
Powered Speaker
System
Digital Capable(TM) designed expressly to meet
the dynamic and low-frequency potential of
digital sound on film
THX approved'
Side-mounted connection panel facilitates
hookup when depth behind the screen is
restricted
Two EVX-180A 18-inch woofers, rated at 2,000
watts of combined continuous program power,
provide very high low-irequency pumping ability
to
below 23 Hz
Unusually exlended
for very-low-frequency synthesized effects, down-
tuned bass guitars or pipe organ
Internal, P1250 power amp delivers 1,200 watts
continuous to the loudspeakers
On-board P1250 processing provides "step-down"
ED, limiting to prevent amp clipping under high-
output conditions, and infrasonic speaker
protection
' THX is a registered trademark of Lucasfilm Ltd.
Directivity
The directional characteristics of the TL88OP
were measured in Electro-Voice's large
anechoic chamber; the test signal was one-
third-octave filtered pink noise at the fre-
quencies indicated. A full spherical measure-
ment system was used. All directional informa-
tion was measured at 6.10 meters (20 feet).
Figure 2 illustrates the horizontal and verti-
cal polar responses. Figure 3 shows the hori-
zontal and vertical beamwidths. Beamwidth
is the angle at which the horizontal and ver-
tical polar responses have decreased in level
by 6 dB when compared to the axial fre-
quency response.
Figure 4 illustrates the total directivity of the
TL880P The directivity factor R,(Q) is the
ratio of the SPL of the TL880P at a given
point to the SPL of an ideal omnidirectional
source at that same point. The directivity
index, D,, is calculated by D, = 10 log,,, R,.
Power Handling
Electro-Voice components and systems are
manufactured to exacting standards, ensur-
ing they will hold up, not only through the
has been aver-
most rigorous of power tests, but also
LF response also appropriate