The piano, and most other instruments, are designed to be heard at a distance. But, a microphone can't always be placed at a distance because it could create feedback problems. Placing a microphone farther away from the instrument can also contribute to a phenomenon called "bleed" or "stage crosstalk." "Bleed" occurs when the microphone picks up unwanted sound from a different instrument.
Knowing about an instrument's directional response helps you position the microphone to achieve the desired effect. Experiment with the microphone placement before adjusting the tone controls.
Bandwidth is the range of frequencies that an instrument produces. It is important to know what frequencies are vital to the sound of an instrument so the proper tone control is adjusted.
You can refine your tone-control-adjusting skills by playing a variety of instrument recordings over the sound system. As you adjust the tone controls, listen through headphones. Then remove the headphones and listen to the sound system. Listen critically to how the sound changes. You will soon understand how adjusting the tone controls affects the sound.
Understanding what frequencies the tone control affects will improve your mix.
Here's an example of how to use knowledge of the instrument's bandwidth to your advantage. Bell choirs can present quite a challenge to sound reinforcement. A typical handbell choir may have bells from G below middle C and up two octaves. The fundamental frequency bandwidth starts at 196 Hz and goes up to 753 Hz. The harmonics extend up many more octaves. Close microphone placement accents individual bells while placing the microphone at a distance picks up more of the full sound. However, placing the microphone at a distance can result in feedback problems and "bleed" from other instruments. Gradually cutting back on the bass tone control can reduce these effects and allow for more freedom of microphone placement. Since the bass control affects frequencies around and below 100 Hz, it will have a minimal affect on the bells. Decreasing the high frequency may also help reduce "bleed" from other instruments. Be careful though! Cutting back the high frequencies may adversely affect the upper harmonics of the bells and make them sound dull and lifeless.
Always listen critically to the results of your adjustment. Don't destroy the overall sound for the sake of a little more volume. And remember, you can't make a poor sounding instrument sound great. If the instrument is not producing those critical frequencies which distinguish a great instrument from a bad one, no amount of knob twiddling will produce a perfect sound.
by Travis Ludwig © 1996 Internet Sound Institute (www.soundinstitute.com). This articles is for personal use only. Any commercial reproduction is not permitted without permission. To obtain permission, contact ISI at hopi@soundinstitute.com
