Tapco T-231 - Manual (Page 7)

7
However, often times a perfectly fl at 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 amplifi er 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 specifi c frequency in the feedback.
This procedure helps to minimize the resonant peaks in the room. It’s a little more diffi cult
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 identifi ed
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 fi ne tweaking
• High-pass fi lter @ 40 Hz to remove unwanted low frequencies
• Low-pass fi lter @ 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