ST-EQ3 Line-Level Audio Equalizer The audio equalizer unit shall be an RDL ST-EQ3. The unit shall provide one balanced line-level audio input and one balanced line-level audio output. The unit shall be equipped with three bands of equalization with a single-turn trimmer provided to adjust each band. The trimmer shall provide a minimum of ± 12 dB equalization at the center frequency of each band. The unit shall include LED indication when either the input or output stage audio peaks clip. An input gain trimmer shall be provided to increase headroom to compensate for equalization boost settings that reduce headroom. The input shall be electronic balanced bridging with an input impedance no less than 100 kOhms and shall be fully compatible with either an unbalanced or balanced audio source. Normal rated input and output levels from the unit shall be +4 dBu. A continuously adjustable multi-turn trimming control shall be provided to reduce the level in the audio input stage. The control shall provide adjustment from “off” to unity gain. Three equalization bands shall be provided. These bands shall be identified on the product as LOW, MID and HIGH frequency bands. The nominal center frequency of the low band shall be 80 Hz. When this band is adjusted for 3 dB of equalization, its nominal bandwidth shall be from 20 Hz to 300 Hz. The nominal center frequency of the mid band shall be 1 kHz. When this band is adjusted for 3 dB of equalization, its nominal bandwidth shall be from 200 Hz to 7 kHz. The nominal center frequency of the high band shall be 30 kHz. When this band is adjusted for 3 dB of equalization, its nominal bandwidth shall be from 3 kHz to 30 kHz. The unit shall provide an un-equalized audio frequency response of 10 Hz to 22 kHz (± 0.5 dB) into a high-impedance load with total harmonic distortion and noise <0.03% and a noise floor exceeding 80 dB below an output level of +4 dBu. The input shall provide common mode rejection greater than 60 dB from 50 Hz to 120 Hz. A clipping indicator shall be provided to indicate audio peaks of an amplitude sufficient to clip. The indicator shall be activated by either of two separate detection circuits, one on the input stage and the other at the output stage. The indicator shall flash when either an input or output signal approaches clipping. The unit shall provide one line-level balanced audio output at a nominal rated output level of +4 dBu with an output impedance of 150 O. The output circuit shall be configured to produce an unbalanced output of proper phase between the positive output leg and ground. The unit shall be constructed in an electrically non-conductive, thermally conductive enclosure. Internal circuitry shall be protected from moisture and vibration using a thermally conductive compound that permanently secures the circuitry within the enclosure. The face of the unit shall provide graphical labels identifying wiring connections and operating controls. The indicator and the gain control shall be oriented toward the front edge of the unit. Equalization trimmers shall be oriented toward the face of the unit. Connection to external wiring shall be provided using a fixed terminal block on the edge of the unit. The terminal block shall accept wiring gauges from 14 to 22 and shall include a positive electrically conductive mechanism to prevent wire abrasion by the terminal screws. The unit shall measure 3” (7.6 cm) x 1.6” (4 cm) x 0.7” (1.7 cm) and be compatible with all RDL STICK-ON mounting accessories. The unit shall be supplied with a two part re-closable polypropylene fastener system equipped with a rubber adhesive that bonds to low surface energy materials. Power requirements shall be 24 Vdc ground-referenced with a maximum current not exceeding 25 mA. The unit shall utilize an external power supply. The unit shall be engineered, assembled and tested in the U.S.A. and be specified for continuous duty in professional installed systems. The unit shall be specified for operation in an ambient temperature between 0 and 55 degrees C. The unit shall comply with relevant EMC requirements and shall bear the CE marking. The unit shall be an RDL ST-EQ3.