Alesis M-EQ 230 DUAL 1/3 OCTAVE PRECISION EQUALIZATION SYSTEM USERS MANUAL
A lesis M-EQ 230 DUAL 1/3 OCTAVE PRECISION EQUALIZATION SYSTEM INTRODUCTION The A lesis MEQ-230 is a two channel, 30 band/channel, 1/3rd octave graphic equalizer which features a relay based power-up delay switching circuit to eliminate turn-on transients in sound systems. Each channel features 30 bands of 1/3rd octave equalization with ANSI and ISO standard center frequencies.
SECTION 1 DESCRIPTION OF CONTROLS FRONT PANEL 1/3 OCTAVE BAND FADER Each 1/3rd octave band is controlled by a center detented fader which provides a boost or cut of 12dB. There are 30 bands per channel. MASTER CHANNEL GAIN FADER Each channel has a Master Gain Fader which controls the system's input gain by ±12dB. CHANNEL BYPASS SWITCH Each channel's EQ can be individually bypassed by means of the Channel Bypass Switch. The Master Gain Fader affects program input level only when the channel is not bypassed.
POWER JACK Accepts the +9VAC power from the M-EQ 230 Power Supply. This external supply keeps hum, noise, and ground loops to a minimum. SECTION 2 SET-UP INSTRUMENTS, MICROPHONES The A lesis M-EQ 230 has high impedance inputs that are ideally suited for use either with instruments or line level signals.
INDEPENDENT USE OF LEFT AND RIGHT CHANNELS The M-EQ 230 need not be used in a stereo mode since each channel is completely independent. In Figure 2 , the right channel is connected to the house sound system for room tuning while the left channel is connected to the on-stage monitor system for feedback control.
INTERFACING VIA INSERT SENDS AND RETURNS Another way of interfacing the M-EQ 230 is to connect the unit directly to the insert send and return patch points (if your console has them) of the channel that is to be effected.
SECTION 3 OPERATION POWER-UP When the power is first turned on, the automatic power-up delay circuit will mute the M-EQ 230 for 2 seconds. This is to prevent any possible turn-on transient signal from mixers, power amps, or outboard equipment from possibly damaging speakers. TO CONTROL FEEDBACK 1 ) Place all microphones in the positions where they will be used. Set mics to approximate levels. 2 ) Gradually bring up the sound system level until feedback just begins to occur.
B) For feedback control, the sliders of the M-EQ 230 should always be operated in the downward or cut position. FIGURE 4 CONTROLLING FEEDBACK A. Find the 2 major feedback frequencies (1 high, 1 low frequency) B. Slightly decrease adjacent bands. A. B. ROOM FEEDBACK FREQUENCIES ADJACENT BANDS SLIGHTLY DECREASED FOR INSTRUMENT TONAL CONTOURING 1 ) Find the desired frequency band by either referring to the Frequency Chart (see Figure 5) or by experimenting.
the same as simply raising the volume level. In this case, do the following: 1 ) With the instrument playing, start by boosting 3 sliders at a time until the offending frequency area is found. (If the Clip LED should light, turn down the Input control) 2 ) Now, decrease the sliders until you are cutting the level instead of boosting. 3 ) Experiment with the amount of decrease of the adjacent sliders as in feedback control (see Figure 4B).
Voice Fullness at 120Hz; Boominess at 200 to 240Hz; Presence at 5KHz; Sibilance at 7.5KHz; Air at 12 to 15KHz Harmonica Fat at 240Hz, bite at 3-5kHz Conga Resonant ring at 200 to 240Hz; Presence and slap at 5KHz Whether used to alter the timbre of an instrument, control feedback, or improve speech intelligibility, it's important to know what effect each portion of the frequency spectrum has on the sound. In summary, the frequency spectrum can be divided up into six important sections.
SECTION 4 SPECIFICATIONS ELECTRICAL CHARACTERISTICS FREQUENCY RESPONSE 25Hz to 20kHz in 1/3 octave increments HARMONIC DISTORTION .004% @ 1KHz @ 0dBV NUMBER OF CHANNELS NOMINAL LEVEL MAXIMUM LEVEL IMPEDANCE 2 0dBV +18dBV 1MΩ OUTPUT NUMBER OF CHANNELS MAXIMUM LEVEL IMPEDANCE 2 +18dBV 240Ω INPUT FRONT PANEL CONTROLS INDICATORS SWITCHES REAR PANEL JACKS POWER 30 Band, 1/3rd octave , ±12dB, center frequencies set to ANSI and ISO standards.
