Telex 309 User Manual

General Product Description

The Electro-Voice® 309 series loudspeaker systems are two-way
loudspeakers with 8-inch low-frequency cones and high temperature
voice-coil assemblies coaxially mounted with wide-dispersion cone
tweeters. The dual magnet construction allows each speaker to be
structurally, magnetically, electrically and mechanically independent
of the other. The 309-8A/309-4T/309-8T utilize a single section
crossover network, centered at 3,000 Hz, which provides 6 dB of
attenuation for the tweeter outside its operating range. The 309-4T
is provided with a 25/70.7/ 100-V line transformer that offers <1 dB
insertion loss and a selection of 0.5-, 1-, 2- and 4-W taps.

The 309-8T is features a 70.7/100-V line transformer that offers <1
dB insertion loss and a selection of 1-, 2-, 4- and 8-W taps.

These components are designed to work together as a complete
system of in-ceiling loudspeakers and accessories. They provide
wide dispersion, high-efficiency, high- maximum output, ease of
installation and wide-range reproduction of music or voice.

WB versions come complete with a pre-mounted ceiling grille.

Architects’ and Engineers’ Specifications

The loudspeaker shall have an 8-inch low-frequency cone radiator
and a coaxially mounted, wide-dispersion cone tweeter. The
loudspeaker shall meet the following criteria: AES power rating shall
be 16 watts of band-limited pink noise (85 Hz to 18 kHz, 6 dB crest
factor). Frequency response will be uniform from 85 Hz to 18 kHz
on both the transformer and non-transformer versions. Pressure
sensitivity, 96 dB SPL at 1 meter (94 dB at 4 feet) on axis with one
watt of band-limited pink noise from 500 Hz to 3 kHz (ref. 20 mPa).
Minimum impedance, 6.0 ohms.

309 Series

8-inch Ceiling

Loudspeakers

COMMERCIAL

The loudspeaker shall be 206.5 mm (8.13 in.) in diameter and

82.5 mm (3.25 in.) deep. Weight shall be 1.3 kg (2.8 lb) [309-8A],

1.4 kg (3.1 lb) [309-4T] and 1.45 kg (3.2 lb) [309-8T]. The 309-4T
shall have a 70-V transformer with taps at 0.5, 1, 2 and 4 watts.
The 309-8T shall have a 70-V transformer with taps at 1, 2, 4 and
8 watts. The maximum insertion loss shall be < 1.0 dB. The
loudspeakers shall be the EV (Electro-Voice
and 3098T with transformer.

®

) 309SA; and 309-4T

Specifications:

Pressure Sensitivity: ............................................................ 96 dB SPL

(1 W, 500 Hz - 3 kHz) re: 20 µPa

Frequency Response: ................................ 85 Hz - 18 kHz (see Fig. 1)

Power-Handling Capacity: ...................................................... 16 watts

85 - 18 kHz, bandlimited pink noise, 6 dB crest factor

Impedance:

Nominal: ........................................................................... 8 ohms

Minimum: .......................................................... 6 ohms (11 kHz)

Maximum Long-Term Output: ........................................... 108 dB SPL

(16 W/1 m) re: 20 mPa)

Crossover Network: ................................................................. 3,000 Hz

with 6 dB-per-octave tweeter protection

Input Terminals: ................................................ .212-in. push terminals

309-8A - Theile-Small Parameters

Free Air Resonance, fs: .............................................................. 110 Hz

Equivalent Volume Compliance,VAS: ......................................... 0.92 ft

Total Q, QTS: ..................................................................................... 0.94

Electrical Q, QES: ............................................................................. 1.16

Mechanical Q, QMS: ........................................................................ 5.03

Volume Displacement VD: .................................................... 1.61 in.

Reference Efficiency: ............................................................. 2.87%

Speaker Frame: ........................................... 22-gauge stamped steel

Finish: ........................................................................................ Black

Dimensions:
309-8A / 309-4T

Loudspeaker Diameter: ............................. 206.5 mm (8.13 in.)

Height: ........................................................... 82.6 mm (3.25 in.)

Net Weight:

309-8A: ................................................................... 1.3 kg (2.8 lb)

309-4T: ................................................................... 1.9 kg (4.1 lb)

309-8TWB: ............................................................. 2.3 kg (5.0 lb)

Shipping Weight:

309-8A: ................................................................... 1.5 kg (3.3 lb)

3

309-4T: ................................................................... 2.1 kg (4.6 lb)

309-8TWB: ............................................................. 2.5 kg (5.5 lb)

Transformer Input:

309-4T ............................................. 25/70.7 (100 volt operation)

3

Recommended Connections

The 309 is a nominal 8-ohm impedance loudspeaker with a 10-watt
input capability. However, it is also available with transformer, the
309-4T, and with transformer and grille, the 309-4TWB.

The 309-4T utilizes a 4-watt, 25/70.7/100-volt universal line
matching transformer with power taps ranging from 0.5 to 4 watts
as indicated in the table for the 309-4T. The transformer is mounted
to the frame and the primary winding is accessible for the user to
select any of the power taps indicated in the table for the 309-4T.

All wattages marked for the various taps refer to the load on the
amplifier, with the insertion loss of the transformer being less than
2 dB.

Recommended Enclosures and Baffles

309-8A and 309-4T are designed to fit on standard 8-inch ceiling
speaker baffles. Additionally, the 209 series loudspeakers will
accommodate the use of any standard back enclosure with a
diameter of 8.6 inches or greater and a depth of at least 3.5 inches.

Larger back volumes will increase the lowfrequency output. The
frequency response of a 209 in a typical 0.25-cubic-foot and

1.8-cubic-foot back enclosure are shown in Figure 1.

Mounting

The 309 may be front- or rear-mounted against either surface of its
mounting flange and requires a 18.4 cm (7.25 in.) diameter cutout
and a 19.5 cm (7.68 in.) bolt circle. Normal fasteners up to 5 mm
(0.20 in.) will fit through the eight holes in the frame. The 309 is
designed for mounting on standard ceiling speaker baffles.

Figure 1, One-Third-Octave Polar Response Charts

Measurements were made in a 1.5 ft3 closed enclosure.