Operating Manual -
when this filter type is combined with a potentiometer to adjust the equalization, the resistance of this pot affects the “Q” of the filter so that a little equalization produces a much broader curve than a lot of equalization.
The other filter approach is a true bandpass fil- ter. This can be made with no inductors and more practi- cal sized capacitors; the “Q” is easily set and remains constant, and the parts count is reasonable. there are sev- eral types of bandpass filters suitable for this job. Ashly uses a “Q” enhanced
In designing a graphic equalizer, a selection of filter sharpness must be made. More sharpness (higher
Q)produces less filter overlap and tighter control over an individual band, but also causes ripple in the frequency response when many filters are boost or cut together to produce a flat response. We feel that the graphic equalizer’s primary use is for “voicing” and tone control, and have set our filter sharpness to produce a maximum of 1dB ripple.
The summing system in a graphic equalizer is also important. Since there are a number of filters which combine to produce the overall response, it is important that the filters not interact (they WILL overlap, but the response of one filter should not modify the response of another). Ashly uses an “interleaved” summing system where every other filter uses the same summing ampli- fier so that adjacent filters never share the same drive and feedback signals. This allows the filters to maintain their natural response.
9.TROUBLESHOOTING TIPS
9.1No Audio Output
Check AC power - is the pilot light on? Check in/out connections - are they reversed? Are you sure you have an input signal?
9.2 EQ Controls Do Nothing
Is the master EQ switch in?
The lowest and highest frequency sliders may be beyond the range of the program material or speakers and may produce little or no audible effect.
9.3 Peak Light Flashes or Stays On All the Time
If the peak light flashes, the signal level to the equalizer is too high. Turn down the gain. If it is on all the time, disconnect the input and output cables. If it is still on, the unit must be returned for service.
9.4 Distorted Sound
This will only be caused by too much signal which will show on the Clip LED. If the LED is not flashing, there is an overload somewhere else in the sig- nal path. Adjust the relative gain of each component in your chain to keep everything at a comfortable level.
9.5 Excessive Hum or Noise
Hum will usually be caused by a ground loop be- tween components. Try using the suggested balanced in- put and output
Noise (excessive hiss) can be caused by insuffi- cient drive signal. Make sure you are sending a nominal 0 dBu line level signal to the equalizer. Most noise prob- lems occur because gain is applied to audio signals too late in the chain. For best performance, apply gain to individual source signals as early as possible, like at the mixer input section. As gain increases, it also boosts the noise content of that signal. Any cumulative noise built up in a mixed signal will only be increased by using an equalizer as a gain device, so make every attempt to op- erate the equalizer with as little gain as possible.
Note: Unshielded cables, improperly wired con- nections, and cable with broken strands (shorts, etc.) are the most common problems. Make sure you use good quality cable with connectors soldered firmly on the cor- rect pin. When in doubt, get in touch with your Ashly dealer, or call the Ashly service department at
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