In a prior article, I mentioned the ways of getting a good acoustic guitar sound through the different types of sound amplification (built-in guitar amp, sound hole pickup, and instrument microphone. In this article, I'll be turning to equalization.
Please note that some of this information is targetted to first-time sound operators, such as the HPF usage. My point is to show how simple it can be to EQ a basic guitar sound.
First things, first…on each channel on the mixer you should find a button, typically near the top, that cuts all low-end frequencies below 80 Hz. This high-pass filter (HPF) might appear as a button with a label of "/80." Press this button (turn on the HPF) so that all frequencies below 80 Hz are cut. Some HPF's run at /100 Hz. These frequencies can muddy the sound of the guitar – give it a rumble quality that is not good.
The HPF option might be used for sounds that aren't focused in the bass range. Those using that range include true bass vocalists, bass guitar, kick drum, electronic keyboard due to range of sounds, and the drum's floor tom. Given time, you'll find sometimes HPF is needed and sometimes it's not. If this is all new to you, start with using the HPF option on.
Now with the lowest of low's out of the way (no tax-collector jokes, please), let's look at the guitar channel's EQ. Slowly cut the low frequency knob until you get a clear sound. While the guitar does have a large octave range, it's just not a bass-heavy instrument. However, because of the 6th and 5th strings being "bass-ier," you can boost the EQ in the 150 Hz range by a few dB's. Test this yourself to find the sound you like.
The following breaks the EQ'ing down into several frequency ranges. Digital work stations can work within the different frequencies. However, the basic channel EQ'ing with only 3-4 knobs will not give the same level of control. Therefore, apply these as they fit best to your situation.
The 150-300 Hz range can be used to beef-up the tone of the guitar but as mentioned, it's easy to get muddy again so only boost frequencies in this area if it clearly improves the sound.
The 300-600 Hz range can be boosted if you have a thin sounding guitar.
The 600-800 Hz range is your meaty mid-range sound. Cut this if necessary to give better tone and better distinguish from other instruments.
Jumping to the 1-3.5 kHz range, these frequencies can push the guitar to the front of the sound mix and effect note definition. Boost these frequencies when looking at fingerpicking-style guitar and guitar riffs.
The 3.5 kHz to 12 kHz range is all about the sparkle. This range adds brilliance and can make the guitar jump out. This range can be further broken down into 3.5-5, 5-8, and 8-12 kHz. Start at the 3.5 to 5 kHz range for adding that sparkle to the acoustic guitar. If you want more, jump to the next range and boost a little there.
Remember that you might be mixing against other instruments that might have their foundational sounds in one of the above ranges. In those cases, you can either boost or cut one instrument's range over the others so the two instruments sound distinctly different instead of stepping on each other.
The guitar is an instrument that produces a wide range of frequencies and depending on properties such as brand of strings, brand of guitar, and type of wood used in the guitar, the overall sound can vary greatly. By default, a great sounding guitar sounds great without the equalization…alone. But when you place that same instrument in a realm with other instruments such as the piano, bass, and violin, equalization is very important not just in bringing out the best in the instrument so everyone can hear, but with blending and setting in its proper place with the other instruments.
For a quick re-cap of those frequencies….
1. Turn on the HPF to drop those low frequencies.
2. 150-300 Hz can be boosted for warmth.
3. 500-800 Hz can be boosted or cut for tone.
4. 1-3.5 kHz can be boosted for single-note playing (fingerpicking and lead lines).
5. 3.5+ Can be boosted for sparkle and brilliance – yes, kind of like a diamond.
Once your comfortable with the guitar EQ process, experiment with the HPF on and off and experiment with other EQ settings.