[. . . ] The loudspeaker(s) shall be capable of handling a 30-watt, 500- to 5, 000-Hz pink-noise signal with a 6-dB crest factor for a period of eight hours. The loudspeaker(s) shall have a diameter of 10. 6 cm (4. 2 in. ) and a depth of 13. 2 cm (5. 2 in. ). They shall have a 2. 41 cm (0. 95 in. ) throat opening with a 1 3/8-18 thread for mounting. [. . . ] The loudspeaker shall be the ID30CT, which includes a 70-V/ 25-V line-matching transformer (see Table II) and weighs no more than 2. 1 kg (4. 5 Ib), and the ID30C8, which has a nominal impedance of 8 ohms (or ID30C-16 with 16-ohm impedance) and weighs no more than 1. 6 kg (3. 5 lb). Medium-Power Compression Drivers COMMERCIAL Architects' and Engineers' Specifications The loudspeaker(s) shall be of the compression-driver type utilizing a rugged phenolic diaphragm and a high-temperature rated, 1. 5-in. The loudspeaker(s) shall exhibit essentially flat power response from 300 to 4, 000 Hz with a smoothly rolled-off response beyond. Their sensitivity, when mounted on a PH horn, will be 107 dB (1 W/1 m) with a 500- to 5, 000-Hz pink-noise signal applied. Specifications: Frequency Response: 300-4, 000 Hz, ±5 dB (see Figure 2) Power Handling, 8 hours, 6-dB crest factor: 30 watts (500- to 5, 000-Hz pink noise) Impedance, Nominal: ID30C-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ohms ID30C-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ohms Minimum, on Cobreflex Horns, Above 500 Hz: ID30C-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. 5 ohms (850 Hz), ID30C-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 ohms (850 Hz), Sound Pressure Level at 1 Meter, 1 Watt Input Average, Pink Noise Band-Limited from 500 to 5, 000 Hz: see Table I Voice-Coil Diameter: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 81 cm (1. 5 in. ) Magnet Weight: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tighten the gland nut securely and reassemble the rear housing by replacing the screws and tightening securely. Transformer Model (1829T) A transformer and power-selector switch are installed in the base of the housing. Transformer wiring with respect to Table II is illustrated by Figure 5. Low-Frequency Driver Protection When frequencies below the low-frequency cutoff for the horn assembly are fed to the driver, excessive current may be drawn by the driver. For protection of driver, amplifier, and transformer (if driver with built-in transformer is used), capacitor(s) in series with driver, or transformer primary are recommended. Values for other frequencies can be determined by using the formula: C200 Values shown in the following table C x 200 f f = New Frequency For drivers without transformers: 8-ohm driver, 25 V - 100 mf Horn Cobreflex IIB Cobreflex III SPL for 1 W @ 1 M 106 dB 106 dB C= [ 200 ] Table I. Sound Pressure Level for 1829 with Various Horns 70-Volt Lines 25-Volt Lines Impedance Capacitance Impedance Capacitance 21 ohms 40 mf 167 ohms 5 mf 335 ohms 2 mf 42 ohms 20 mf 500 ohms 1. 3 mf 63 ohms 13 mf 1, 000 ohms 0. 7 mf 125 ohms 7 mf 2, 000 ohms 0. 4 mf 250 ohms 4 mf 4, 000 ohms 0. 2 mf 500 ohms 2 mf Power 30 W 15 W 10 W 5W 2. 5 W 1. 25 W Table II. Disortion Response - Plane Wave Tube (1 inch) (6 watt input) Figure 2. [. . . ] Disortion Response - Plane Wave Tube (1 inch) (6 watt input) Figure 2. Impedance Response - Plane Wave Tube (1 inch) USA Canada Switzerland Germany France Australia Hong Kong Japan Singapore Mexico UK Africa, Mid-East Latin America 12000 Portland Ave South, Burnsville, MN 55337, Phone: 952-884-4051, FAX: 952-884-0043 705 Progress Avenue, Unit 46, Scarborough, Ontario, Canada, M1H2X1, Phone: 416-431-4975, 800-881-1685, FAX: 416-431-4588 Keltenstrasse 11, CH-2563 IPSACH, Switzerland, Phone: 41/32-331-6833. FAX: 41/32-331-1221 Hirschberger Ring 45, D94315, Straubing, Germany, Phone: 49 9421-706 392, FAX: 49 9421-706 287 Parc de Courcerin, Alle Lech Walesa, Lognes, 77185 Marne La Vallee, France, Phone: 33/1-6480-0090, FAX: 33/1-6480-4538 Unit 23, Block C, Slough Business Park, Slough Avenue, Silverwater, N. S. W. [. . . ]