How to Alter a Harp’s Sound with Effects
When you play through amplification, whether you cup the mic or not, you can use several effects that enhance your amplified harmonica. Some effects enhance the natural sound of the harmonica, while others are designed to actually alter the instrument’s sound. Here are the most useful effects for harmonica:
Equalization (EQ): With EQ you can boost some parts of the sound spectrum and de-emphasize others to make your overall tone darker, brighter, or warmer. EQ can also counter some of the thin sound associated with the harmonica.
For instance, emphasizing frequencies around 250 Hz can make the harmonica tone sound thicker. (Hz is the abbreviation for Hertz, which measures vibrations per second.) Rolling off, or strongly reducing, the highest and lowest frequencies (below about 150 Hz and above approximately 6,000 Hz) can help you avoid feedback.
Compression: Also called limiting, compression reduces the extremes of loud and soft in your playing so that loud sounds aren’t too loud and soft sounds aren’t inaudible. Compression delivers a louder-sounding signal without turning up the volume. It also helps avoid feedback and gives you a richer sound.
Delay: This effect sends some of the signal from your mic directly on to the next point while delaying another part for as little as a few thousandths of a second. At this point, the signal is delivered as one or more distinct repetitions. Delay helps the harmonica sound fuller and richer.
Reverberation (reverb): This creates the impression of ambient sound reflecting off the walls of rooms of various sizes. Reverb can create the impression of sound occurring in a large space. However, remember that reverb is easy to overdo.
Distortion units: A distortion unit contains two preamps, or small amplifiers that boost the mic signal at an early stage in the amplification process. One preamp overdrives the other to create distortion. An effect unit is only one of many ways to create distortion.
Feedback suppressors: As the name implies, these units are designed to prevent feedback. Feedback suppression is especially useful when playing through an amplifier at high volume levels.
Most sound systems have EQ, compression, delay, and reverb built into the mixing board. So when you’re playing through the house sound system and have time to dial in effects before the performance, you can ask the sound tech to adjust these effects to give you a fuller harmonica sound.
Musicians often use stomp boxes, small metal boxes that contain a single effect. You adjust the box to the desired setting, place it on the floor, and then turn it on or off with a foot switch. Stomp boxes are usually made for electric guitar, but they can be adapted for harmonica as well.
If you look at a harmonica player’s onstage rig, or amplification equipment, you may see a whole series of stomp boxes all plugged into one another in a chain, ready to be activated in various combinations at the tap of a toe. If you have your mic connected to one or more effects units onstage, you can send the signal to the sound system or to an instrument amplifier.