User manual SAMSON S131MEUS

[. . . ] S Class Signal Processors 31 BAND EQUALIZER Safety Instructions Caution: To reduce the hazard of electrical shock, do not remove cover or back. Please refer all servicing to qualified personnel. WARNING: To reduce the risk of fire or electric shock, do not expose this unit to rain or moisture. The lightning flash with an arrowhead symbol within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. Important Safety Instructions 1. [. . . ] (See the owners manual for your specific power amplifier for the proper bridge mode operation. ) 8 S curve 131 System Configurations Using the S curve 131 in Insert Points You can use the S curve 131 in your mixer's insert points if you want to equalize a mono channel, individually in the mix. In this example the S curve 131's Channel 1 INPUT and OUTPUT are inserted on a bass guitar channel using a 1/4-inch TRS to 2 x 1/4-inch TS "Y" cable. For more information on cable wiring see the S Curve 131 Wiring Guide page 15 in this manual. Using the S curve 131 for Mains and Monitors In this example an individual S curve 131 is used for both the main PA speakers running a mono mix, and for the monitor mix, also in mono. For the main PA, the mixer's MONO output is connected to the S curve 131's input. Then, the S curve 131's output is connected to the input of the right main PA active (self-powered) loudspeaker. The left main PA speaker is connected by "daisy-chaining" from the right. For the monitor mix, the mixer's AUX1 output is connected to the second S curve 131's input. The S curve 131's output is connected to the input of the monitor power amplifier operating in bridge mode. Finally, the power amplifier's outputs are connected to the passive (non-powered) monitor loudspeakers. (See the owners manual for your specific power amplifier for the proper bridge mode operation. ) 9 S curve 131 System Configurations Using Two S curve 131's for Mains and Monitors 10 In this example two S curve 131's are used for the stereo main and for the 2-channel monitor mix. The mixer's left and right outputs are connected to the first pair of S curve 131's inputs for the main PA speakers. Then, the outputs are connected to the inputs of the active (self-powered) loudspeakers. For the monitor mix, the mixer's AUX1 output is connected to the third S curve 131 and AUX2 output is connected to the fourth S curve 131's input. Then, the outputs are connected to the inputs of the 2-channel power amp. Finally, the power amplifiers outputs are connected to the passive (non-powered) monitor loudspeakers. About Equalization The S curve 131 gives you fine control over shaping a sound, using a process called equalization. But there are few areas of sound engineering more misunderstood than equalization, and, just as good EQ can really help a sound, bad EQ can really hurt it, so read on. . . Every naturally occurring sound consists of a broad range of pitches, or frequencies, combined together in a unique way. The range of frequencies that can be heard by humans is sometimes called the audible range, and it includes frequencies from as low as 20 Hz (that is, 20 wavecycles per second) to those as high as 20 kHz (that is, 20, 000 wavecycles per second). The S curve 131 uses high-quality filters, dividing the audible range into 31, 1/3 octave frequency areas, centered at 20 Hz, 25 Hz, 31. 5 Hz, 40 Hz, 50 Hz, 63 Hz, 80 Hz, 100 Hz, 125 Hz, 160 Hz, 200 Hz, 250 Hz, 315 Hz, 400 Hz, 500 Hz, 630 Hz, 800 Hz, 1 kHz, 1. 25 kHz, 1. 6 kHz, 2 kHz, 2. 5 kHz, 3. 15 kHz, 4 kHz, 5 kHz, 6. 3 kHz, 8 kHz 10 kHz, 12. 5 kHz and 16 kHz, 20 kHz "Constant Q" circuitry ensures that the bandwidth of each of these frequency areas stays the same even when approaching maximum boost or attenuation resulting in greatly reduced phase shifting and intermodulation distortion. Each frequency area can be cut or boosted by as much as 12 dB, giving you finer control and allowing you to construct gentler frequency curves. In most instances, the best way to approach equalization is to think in terms of which frequency areas you need to attenuate, as opposed to which ones you need to boost (boosting a frequency area also has the effect of boosting the overall signal; too much EQ boost can actually cause overload). Be aware of the phenomenon of masking, where loud sounds in one frequency range obscure softer sounds in the same range; by cutting EQ "notches" in a loud signal, you can actually make room for a softer one to shine through. [. . . ] Be prepared to compromise--and if there's a discrepancy between what the RTA says and what your own ears tell you, always go with the latter. Bear in mind that an analyzer "listening" to pink noise is no substitute for the human ear listening to actual program material. A perfectly flat frequency response is not necessarily the best sounding frequency response, so, once you have used the RTA and the S curve 131 to tune a room "by the numbers, " be sure to audition the results by playing typical audio signal (music, speech, etc. ) through your system and continue to fine tune by ear. Be prepared to compromise--and if there's a discrepancy between what the RTA says and what your own ears tell you, always go with the latter. 13 Using the S curve 131 to Remove Feedback One of the most important applications for the S curve 131 is removing feedback from an onstage monitor system. This procedure is sometimes called "ringing out, " since feedback usually begins with a slight ringing sound at the resonant frequencies where the loop between microphone and speaker is loudest. [. . . ]