Tapco T-231 user service Bypass switch allows quick A/B comparisons

However, often times a perfectly flat frequency response is not what you want in a live sound application. For example, if the low-frequency response of the loudspeakers only extends to 50 Hz, there is no need to amplify the frequencies in the lowest octave of the audio frequency range, 20 Hz to 40 Hz. You can use the T•231 to roll off these frequencies, which reduces the drain on the amplifier and provides more power to amplify the higher, more useful frequencies.

You might want to boost the higher frequencies a bit to add brightness and sizzle to the sound. If the sound system is for the speaking voice, boosting the mid frequencies around 2-4 kHz can improve the intelligibility of the voice. Boosting 125 Hz, 250 Hz, and 16 kHz can improve a vocal. Try as you might to eliminate it, there may still be a residual 60-cycle hum in the speakers. You can use the 63 Hz slider to notch down the hum (the 125 Hz slider can help eliminate residual buzz).

A graphic equalizer can be used to reduce feedback. If you don’t have a real-time analyzer to identify the peaks that cause the feedback, you can do a fairly good job by ear using the following procedure.

1.Set all the sliders on the T•231 to the center position (zero).

2.Slowly turn up the master volume on the mixer until feedback just begins to occur. You can usually hear a soft ringing sound that gradually increases in volume. BUT BE CAREFUL! Feedback can occur quickly and become very LOUD, very fast.

3.Cut the appropriate slider, corresponding to the feedback frequency, until feedback stops. It may take some practice to identify the frequency where the feedback is occurring, but your accuracy will improve the more familiar you become with it.

4.Repeat until you can’t isolate a specific frequency in the feedback.

This procedure helps to minimize the resonant peaks in the room. It’s a little more difficult to identify and adjust for dips in the room response. This is best done from experience listening for gaps in the sound of particular instruments or voices. Once you’ve identified them, boost the slider for that particular frequency range by 3 to 6 dB to help smooth the frequency response.

Another application for a graphic equalizer is patching it into a channel insert to enhance the sound or change the tonal characteristics of a vocal or instrument (see hookup diagram). The Sound Frequency chart on page 18 is a good reference to locate the frequency ranges of particular voices and instrument.

The Tweeq Series™ of processors are powerful and tough. They are designed to withstand the punishing rigors of the road and continue to perform day after day, year after year.

Here’s a quick glance at the features packed into the T•231:

•2-channel 31-band graphic equalizer with constant Q circuitry and great sound quality

•Switchable 6 and 12 dB control range for wide or fine tweaking

•High-pass filter @ 40 Hz to remove unwanted low frequencies

•Low-pass filter @ 16 kHz to remove unwanted high frequencies

•Bypass switch allows quick A/B comparisons

•Independent signal clip indicators on each channel

•Input gain control for EQ signal compensation

•Balanced 1/4" TRS and XLR, and unbalanced RCA input and output jacks

•Selectable line voltage

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