Description
The Altec-Lansing 407 series are high-qual-
ity 6.5-inch duplex loudspeaker for distrib-
uted sound systems available in three ver-
sions: standard 8-ohm (407-8A), 8-ohm
with 8 W transformer (407-8T) and 8-ohm
with 16 W transformer (407-16T).
The loudspeakers feature 6.5-inch low-fre-
quency cones and high-temperature voice-
coil assemblies coaxially mounted with
wide-dispersion neodymium tweeters. The
dual-magnet construction allows each
speaker to be electrically and mechanically
independent of the other. The 407-8A loud-
speaker utilizes a crossover network, cen-
tered at 3,000 Hz, that provides tweeter pro-
tection outside of its operating range.
The 407-8A is suitable for use in applica-
tions requiring highly intelligible speech or
smooth musical reproduction.
To ensure long-term reliability in instal-
lations, the 407-8A is designed to handle
16 watts continuous power (64 watts peak)
of shaped white noise for eight hours per
ANSI/EIA RS-426-A 1980.
The 407-8T utilizes a transformer that of-
fers a selection of 1-, 2-, 4- and 8-watt taps
delivered to the loudspeaker system using
either 70-V or 100-V lines.
The 407-16T utilizes a transformer that of-
fers a selection of 2-, 4-, 8- and 16-watt taps
delivered to the loudspeaker system using
either 70-V or 100-V lines.
Directional Performance
The directional characteristics of the 407-8A
in a 1.8 cubic-foot vented enclosure were
measured by running a set of polar responses
in Altec Lansing's large anechoic chamber.
The test signal was one-third-octave-band-
limited pseudo-random pink noise centered
at the ISO standard frequencies indicated in
Figure 1.
Additional typical data is provided in
Figures 4 and 5, which indicate 6-dB-down
beamwidth versus frequency and directivity
factor, respectively, for a 407-8A in the test
enclosure.
Power-Handling Test
The 407-8A is designed to withstand the
power test described in ANSI/EIA RS-426-A
1980. The EIA test spectrum is applied for
eight hours. To obtain the spectrum, the out-
put 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 mea-
sured with a usual constant-percentage-band-
width analyzer (one-third-octave), this
shaping filter produces a spectrum whose
3-dB-down points are at 100 Hz and 1,200 Hz,
with a 3-dB-per-octave slope above 1,200 Hz.
This shaped signal is sent to the power ampli-
fier with the continuous power set at 16 watts
into the EIA equivalent impedance (11.3 volts
true RMS). Amplifier clipping sets instan-
taneous peaks at 6 dB above the continuous
power, or 64-watts peak (22.6 volts peak).
This procedure provides a rigorous test of
both thermal and mechanical failure modes.
Recommended Connections
The 407-8A is a nominal 8-ohm impedance
loudspeaker with a 16-watt input capabil-
ity. The 407-8T utilizes an 8-watt, 70.7-,
100-volt universal line-matching trans-
former with power taps ranging from 1 to
8 watts. The 407-16T utilizes a 16-watt,
70.0-, 100-volt universal line-matching
transformer with power taps ranging from
2 to 16 watts.
Recommended Enclosures and Baffles
The 407-8A, 407-8T, 407-16T are designed
to fit on standard 6.5-inch ceiling speaker
baffles. Additionally, these loudspeakers will
407 SERIES
6.5-Inch Duplex Full-
Range High Performance
Ceiling Loudspeakers
•
407-8A
407-8A
407-8A
407-8A
407-8A
, 8 ohm,16 watts
(EIA RS-426-A)
•
407-8T
407-8T
407-8T
407-8T
407-8T
, with 8 watt multi-tap
transformer
•
407-16T
407-16T
407-16T
407-16T
407-16T
,with 16 watt multi-
tap transformer
•
High efficiency: 93 dB for 1W @ 1M
•
Maximum SPL: 105 dB for
16W @ 1M
•
Frequency response: 95 Hz - 18 kHz
•
Wide dispersion
•
Duplex construction
