Step 5: System Adjustment and Acoustic Tuning
The Sx600 MUST BE HI-PASSED at 90Hz using a minimum slope of 12dB/octave with a Q of 1.6. (Easily obtainable on the Electro-Voice Dx- 38 Digital Loudspeaker Controller) If analog filtering is used, a 70Hz high-pass filter of at least 12dB/octave slope and low frequency EQ of NO MORE THAN 3dB boost centered at 90 or 100Hz not to exceed one octave wide is acceptable. Do not use shelving EQ! Set the system limiters to prevent amplifier clipping even during extreme (aka: excited announcer) program peaks. EQ cuts are acceptable when necessary to account for resonances within the venue, but DO NOT BOOST EQ. The Sx600 has a full, natural sound, but has no usable output below 70 Hz.
Appendix A: Troubleshooting
Every Sx600 is thoroughly tested before it leaves the Electro-Voice factory. Listed below are some of the common problems that may be encountered along with suggestions for solving them.
Speaker plays but level is low:
1.) Make sure the amplifier is capable of delivering sufficient voltage and current to produce the wattage necessary for the total number of systems per line.
2.) Check amplifier input drive signal level and gain adjustment. Verify that amplifier is developing the required output voltage and that the voltage at the loudspeaker is the same.
3.) Excessive line loss. Verify that wire size is adequate for the length of run, especially on 4 ohm PI models. If wire gauge is too small, either rewire, change to the constant-voltage PIX version, or on PIX models, change to a higher voltage tap to reduce line loss, providing the amplifier is able to deliver that voltage without clipping and the wiring will still meet code requirements at the higher voltage.
4.) Incorrect voltage tap setting. (PIX models only) Setting the tap higher than the line voltage will reduce the wattage drawn from the line, resulting in 3dB less level (1/2 the wattage) for each tap above rated voltage. Verify and re-set taps as necessary. Setting the taps below the line voltage (PIX models) or attempting to drive too low an impedance (PI models) may cause the amplifier to go into over-current protection resulting in decreased output. Redistribute lines and/or add more/higher power amplifiers.
