User manual DLS MRA41

[. . . ] Contents How to install and operate the DLS Marine Audio amplifiers MRA22 MRA31 MRA41 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amplifier installation kit. . . . . . . . . . . . . . . . Wiring Power and Remote. . . . . . . . . . . . . . . . . . . . . Input and controls Input wiring Hi & Low level. . . . . . . . . . . [. . . ] This function is used to compensate for the bass box function and to adjust for your own taste of bass. Set level control at 0 dB if you want it to be inoperative. The HPF (high pass filter) blocks very low frequencies from reaching the speakers. It is mostly used at say 60 Hz to protect small speakers (like 6 inch and smaller) from deep bass. It can also be used as subsonic filter to take away the very deepest frequencies from a bass box. The typical setting is then around 25 ­ 40 Hz. The filter can be switched off if you want to run the amplifier in full range mode. On MRA41 the filter can also be used for active crossover in a 2-way speaker component kit, a typical crocssover point is then 3, 5 - 4 kHz. 5 MRA41 The MRA22 is a two channel stereo amplifier. It has a variable high pass filter, (HPF) 15-500 Hz. It has also a variable low pass filter, (LPF) 50-500 Hz for subwoofer use. HPF 50Hz 220Hz LPF 80Hz 200Hz 15Hz 500Hz 50Hz 500Hz Off On Off On The MRA41 is a four channel amplifier. It is mostly used with a front system connected to channels C/ D and a subwoofer connected to channel A/B. You will find speaker wiring and filter setting example on page 9. Please observe the proper settings of the channel A/B LPF multiplier switch and of the channel C/D HPF multiplier switch. The MRA41 can also be used to feed a 2­way front system with active crossovers between midbasses and tweeters. This is described in a speaker wiring and filter setting example on page 10. LPF Multiply 80/800Hz 200/2(k)Hz Off On50/500Hz 500/5(k)Hz x1 x10 HPF Multiply 50/500Hz 220/2(k)Hz The MRA31 is a three channel amplifier. It has a variable high pass filter, 50-150 Hz, for channel A/ B. The C channel is for subwoofers and has a subsonic filter, a variable low pass filter, 50-120 Hz, and a phase control variable from 0 - 180 degrees. The subsonic filter can be switched IN-OUT and has a fixed frequency of 25 Hz. Off On 15/150Hz 500/5(k)Hz x1 x10 Channel A/B is equipped very much like the MRA22, however the LPF has a multiplier. Thus the frequency range of the LPF can be varied from 50 Hz ­ 500 Hz in the x1 position or 500 Hz ­ 5 kHz in the x10 position. This way we can use this amplifier to feed a 2way system, where the midbasses are fed from 80 Hz ­ 4 kHz. The tweeters connected to channel C/D , operate from 4 kHz upwards using the HPF in multiplier position x 10 150 Hz ­ 5 kHz. 6 MRA22 Speaker wiring MRA 22 Two fullrange speakers to MRA22 One subwoofer connected in bridge mode to MRA22 NOTE!4 ohm minimum load when using bridge mode connection. [. . . ] Out of phase speakers will cause a lack of bass, and a poor stereo soundstage. Checking polarity: Hold the - connection of the speaker wire to the terminal of a 1, 5 Volt flashlight battery. Tap the + wire on to the + terminal of the battery, and observe the movement of the cone. The cone should move outwards when the wire touches the battery, and inwards when the battery is removed. [. . . ]