Most of us will need to amplify our upright bass at some point. Besides… you know you want to! When amplifying your bass, there are a number of components involved in creating the sound that comes out of the speakers. Today, let’s consider a few of them.
Of all the things involved in amplifying the upright bass (pickups, amps, speakers, EQ, etc.) the acoustic sound of your instrument matters the most. Get yourself the best sounding bass you can and set it up well. Use strings that compliment the instrument and fit your playing style. You can make a cheap, plywood bass sound better with EQ’s, amps and speakers, but the better your acoustic sound, the better your amplified sound potential.
When it comes to turning your acoustic sound into an audio signal, you have a plethora of choices. Basically, however, you are looking at four options:
This might be a microphone especially designed for the upright bass, or it might not be. It may be attached to your instrument, or it could be on a mic stand in your general vicinity. Whatever the case is, microphones all operate the same way. They pickup up the vibrations in the air and turn it into an audio signal.
There are several types of microphones (condenser, ribbon, etc.), and several polar patterns (i.e. the microphones directionality) to consider. For live amplification of the upright bass I would suggest a condenser microphone with a cardiod, hypercardiod or shotgun pattern. I advise against omni-directional or figure 8 patterns. Condenser microphones require power of some sort. Some will come with small battery powered preamps, others will not.
Of your options, microphones generally give the most accurate representation of the acoustic sound of your instrument. This is good… if you have a decent sounding bass. This is bad if you have an instrument with a less than evocative sound.
When using a microphone, the feedback potential can be great, even at moderate volume levels. Mics can be used at high volumes provided there are certain factors in place, such as a considerable distance between you and the speaker. For those of us who play in cramped clubs at high volumes with our amps right behind us, using a microphone is generally not our best option.
There is also the question of “bleed” to consider. Use a mic and sit close to the drums for a gig and see what I mean.
2. Transducers or Piezo pickups.
These types of pickups are primarily designed to detect the vibration of the instrument, i.e. the wood. They are attached directly to the instrument: Underneath the bridge, on the bridge, in the bridge, on the belly, on the fingerboard, etc.
Transducers are more feedback resistant than microphones, but not as accurate in replicating the acoustic sound of the instrument. Transducers are the most common way turning an upright bass sound into an audio signal.
3. Magnetic pickups:
This is the type of pickup found on most electric bass guitars. To create a signal they use…magnets. They are designed to detect the vibrating string and use this information to create an audio signal. They only work if you are using strings with a steel content, otherwise…uncomfortable silence. They produce a sound almost entirely unlike the acoustic sound of your instrument, but they provide a high level of feedback resistance.
4. Combinations of the above:
It is not at all uncommon for bassists to use microphones, transducers and magnetic pickups in combination. Neither is it uncommon to have a variety of approaches for assorted musical settings.
For example: I use two transducers (one under the bridge and one under the fingerboard) for traditional Rockabilly. I use both a magnetic pickup and a fingerboard transducer for Psychobilly. I use a bridge transducer and a magnetic pickup when I play jazz combo or with a big band, and since 1995 I have used a magnetic for all my looped/amplified solo projects, or anything incorporating heavy use of EFX. Your specific situation will determine what combination works best for you and your specific musical situation.
One thing to remember is that neither microphones nor pickups operate exactly like your ears. Nothing involving a speaker will ever quite sound like your bass does acoustically. The upside is that if you have a cheap bass, you can hide some of the imperfections with the magic of pickups, amps, speakers and EQ.