User manual MARTIN AUDIO AM404 SCHEMATICS

[. . . ] Subject to change without notice. A combined WLX/W8LM grid (ASF20003 ­ not shown) has been designed to enable W8LM miniature line array elements to be flown beneath standard WLX subwoofers. Rear connector brackets (ASF20005) are also available for flying W8LC compact line arrays below WLX subwoofers. ASF20005 connector brackets enable WLX subwoofers to be angled downwards with respect to the W8LC compact line arrays to ensure optimum audience coverage. Connector Bracket Application example For detailed rigging information, please see the WLX Flying Manual. Specifications Freq response: Rated Power: Sensitivity: Maximum SPL: Impedance: Connectors: Dimensions: Weight: 35Hz - 150Hz +/- 3dB (half space) 1000W into 8 Ohms, 4000W peak 106dB (half space with band limited pink noise) 135dB continuous, 141dB peak (half space with band limited pink noise) 8 Ohms nominal 2 x Neutrik NL8 or PAcon to special order (W) 1002mm x (H) 490mm x (D) 800mm (950mm with wheelboard) (W) 39. 45ins x (H) 19. 3ins x (D) 31. 5ins (37. 4ins with wheelboard) 89 kg (196 lbs) All material © 2007. Subject to change without notice. Pin-outs and cabling WLX Input NL8 -1 +1 -2 +2 -3 +3 -4 +4 WLX Driver ­ (& link -1) Driver + (& link +1) Driver ­ (& link -2) Driver + (& link +2) link -3 link +3 link -4 link +4 All material © 2007. [. . . ] Martin Audio MA series power amplifiers have regulated rails so it is quite permissible to use slightly All material © 2007. Subject to change without notice. overpowered models - with suitably set controller limiters - without risking uncontrolled power bursts. The MA series power amplifiers' regulated power rails also ensure maximum performance under the real-world concert conditions of less-than-optimum mains supplies and low impedance loads. Amplifier load tolerance An efficient subwoofer system in live concert conditions can act as a surprisingly dynamic and complex load. Most modern touring power amplifiers claim 2 Ohm capabilities but make sure your amplifier is also capable of driving reactive (ie inductive or capacitive) loads without prematurely clipping or developing output stage crossover distortion. Mains safety! A fully qualified technican should check mains safety and phase voltage before the system is patched. Power reserve Most power amplifier specifications are based on bench measurements made using stable, high current mains supplies and well defined loads. Amplifiers sound best when they have plenty of current in reserve for percussive peaks and sustained bass notes. 1) Try to ensure that the mains supply stays within the amplifier manufacturer's specified range from no load to maximum load. An electrical technician should check the supply vs demand using an accurate voltage meter. 2) If unfamiliar generators are being used the electrical technician should check the mains waveform (using a portable 'scope-meter) to make sure that it is sinusoidal and not crawling with spikes or interference. Avoid driving too many WLXs in parallel. I would suggest no more than two (giving 4 ohms) so that the power amplifier's 2 Ohm spec is kept in reserve for musical peaks. Avoid using power amplifiers in bridged mode. Use short stacks for short, wide vertical shots. Use tall, electronically steered, stacks to project to high, distant seating ­ see later. Vertical Boundary effects As mentioned before, a solid floor will act as a reflector. This will cause a vertical stack to perform as if it were double the length, giving a useful low frequency boost and a narrower vertical polar response. All material © 2007. Subject to change without notice. For instance, an 8 high ground-based stack of WLX/AM404 subwoofers will act like the top half of a 16 high stack. It is possible to reach higher seating areas whilst retaining a tall vertical stack by electronically "tilting" the system - see later. Note that flexible floors may actually absorb sound at some frequencies so the situation isn't always so simple in practice. Horizontal - 6dB coverage The following table gives the approximate horizontal coverage angles of typical WLX/AM404 arrays ignoring boundary effects. WLX/AM404 Wide 43Hz 2 4 8 16 Wide Wide 75º 35º Horizontal coverage 86Hz 172Hz Wide 75º 35º 17º 75º 35º 17º 9º Use wide arrays for long shots. Useful for long, narrow venues Use narrow arrays for short, wide shots Horizontal Boundary effects A solid wall near an array will act as a reflector. This will cause a horizontal array to perform as if it were twice as wide, giving a useful low frequency boost accompanied by a narrower, more complex polar response. All material © 2007. Subject to change without notice. Again, a flexible side wall may absorb sound at certain low frequencies. [. . . ] Subject to change without notice. Addition & Subtraction The above shows how two pairs of sine waves (with identical amplitude and frequency characteristics) will sum. Pair (b) are out of phase and cancel. All material © 2007. Subject to change without notice. Polar variations with frequency Whether particular frequency components add or subtract in the far field will depend on the loudspeaker system spacing, the angular offset of the listener with respect to the centre line, and the wavelength. The following polar responses show what happens when subwoofers are placed 8. 6m apart and are driven in unison at various frequencies: 100Hz The polar plot shows the far field polar response of the two subwoofers when driven in phase with the same 100Hz signal. [. . . ]