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One might think that mandolins have double strings to provide additional notes. Others believe it is to make techniques like tremolo picking easier. But the real reason is rooted in the science of sound.
Mandolins have double strings to provide stronger vibrational energy from the strings. This produces tones that have a fuller sound and sustain a longer resonance of higher strength than a single string can produce. Instruments were given double strings to amplify their sound.
This can be explained with some basic knowledge in acoustics, which will be covered briefly here. But first, let’s start by understanding more about the double-string feature in stringed instruments to better understand why mandolins have double strings.
A Short Course in String Courses
If you have not played a string instrument before, you may not be familiar with the term course as part of music vocabulary. A course is a set of two or more strings that are spaced closely together and are meant to be played simultaneously. An instrument with string courses is considered a coursed instrument. Conversely, all instruments with strings that are all played individually, such as a classic six-string guitar or a ukulele, are known as uncoursed instruments.
When a single string is set among coursed strings, that lone string may also be described as a course, but only in this situation. An example of this would be a nine-string baroque guitar with five courses: four 2-string courses and one 1-string course. Other course instruments that you most likely heard of include the eight-string bass guitar, the twelve-string guitar, the lute, and the piano.
String Courses on Mandolins
In general, mandolins are made with 4 two-string courses. This means that there are 8 strings on the mandolin but they are in pairs making it play like a 4-string instrument.
Tuning a String Course
The strings that are set together in a course may be tuned in one of three ways:
- To the same pitch (in unison)
- To the same note in different octaves
- To different pitches
Each choice provides a different effect. Some sheet music and certain songs may be written with a specific tuning in mind, and may even recommend a certain tuning to create the sounds composers intended upon.
In general, mandolin courses are tuned to the same pitch and we will discuss the reason for this in a moment. But at the end of the day, it’s ultimately your decision as to how you tune your instrument and what sound you like most.
Tuning A Mandolin
Like any stringed instrument, the mandolin has a standard tuning that is used in most cases. Standard tuning for a mandolin is known as G-D-A-E tuning and is also the same tuning found on a violin. The exception is that rather than four strings to tune as you would have on the violin, you have to tune eight strings on the mandolin.
The following image shows the standard tuning on a mandolin and the note that each course should be tuned to.
How Double Strings Amplify the Mandolin
It is believed that multiple string courses were utilized to further amplify instruments before the existence of electric amps or electricity. The mandolin is certainly an instrument that qualifies for volume assistance. This correlates with the build of the instrument and its ability to project sound.
As mentioned previously, mandolins typically tune strings coursed together to the same pitch. Also, the strings of the same course are meant to be played simultaneously. Apply what was discussed, and we can surmise that by plucking two strings wherein each provides the same frequencies, the vibrational energy is concentrated, which provides an amplification of resonance so the mandolin can project with more volume.
I can attest to this phenomenon when trying it out on my own mandolin. Plucking both strings within a course has a fuller sound and has longer sustain than it does if I pluck only one string at a time.
Strictly speaking, how hard you pluck the mandolin strings will determine the amount of energy the sound wave has and how loud the sound is. Additionally, the design of the mandolin body plays a role in providing amplification. Specifically, the shape of the body and the sound holes are important factors.
Sound Holes
Sound holes are located on the face of the body either behind the strings or off to the side near the body’s edge. The soundholes located near the body’s edge are known as F-holes and are the most common in the majority of mandolins on the market.
These sound holes are not the only reason sound resonates from the instrument, but they are a significant factor in amplifying the sound. This is because vibrations also come from the string when it is plucked. Since the strings are attached to the body, the vibrations travel through it as well.
Since the body of the instrument is hollow, this creates a chamber in which the vibrating air will resonate. The soundhole provides a way for vibrations to escape out to the surrounding air. Without a soundhole, vibrations would otherwise be trapped inside of the instrument. If this were the case, we would still hear a sound. It would just be a much quieter tone coming from the string itself.
To be more specific, the sound is amplified because it is concentrated. That is, the vibrations are being forced to travel into a focused direction rather than scattered in all directions. The soundhole provides that point for a concentrated escape. Additionally, the size of the soundhole directly affects the volume as well. The larger the soundhole, the louder the volume, and the smaller the soundhole, the softer the volume.
Use Heavier Strings for Stronger Amplification
Strings are generally described as light, medium, or heavy, correlating to how much tension the strings put upon your mandolin. The more tension there is, the stronger the vibrations are, and the louder the sound is. Therefore heavier strings will produce stronger amplification. Here are a few suggestions to try:
- D’Addario EJ75 Phosphor Bronze Mandolin Strings provide a warm and bright tone
- DR Strings Mandolin: 12, 16, 28, 41 claims to last longer and provide superior sound
- Thomastik-Infeld 154ST Mandolin Strings are used by students and professionals alike but are very expensive.
It is possible to damage some types of mandolins by using heavy strings if it is designed to be compatible with light or medium strings. So be sure to do some research on your instrument, if necessary, to determine if using heavy strings is a practical option for you.
Pros Of Double Strings
- Sound amplification. With two strings instead of one for each note, there is a greater amplification of the sound of the instrument. This helps a small instrument like the mandolin to be able to project a louder sound.
- Tone. One of the advantages of having double strings is the unique sound that it provides. It’s one of the reasons for the unique choppy sound that comes from the mandolin.
- Broken string, no problem. If one of the strings breaks within a course on the mandolin, there is no need to panic.
Cons Of Double Strings
- More strings to mess with. You’ll have eight strings that could need to be replaced often depending on how much you play. It will also be more maintenance as there are more strings to break.
- More strings to tune. Keeping a mandolin in tune can be a challenge. You may find yourself constantly making fine-tune adjustments in order to keep each course in tune. You’ll have eight strings to worry with.
- More tension on your instrument. Eight steel strings can put a lot of tension on an instrument. Thankfully, the neck is short on a mandolin and shouldn’t bow as easily as a longer neck instrument might. Some mandolins don’t have a truss rod so you’ll need to be careful with the type of strings that you use.
- More difficult on your fingers. Pressing two strings down at one time is more difficult than pressing one string down. As a beginning mandolin player, I have noticed quite a difference in the difficulty in this. It’s important to have your action set properly if you want to minimize the difficulty involved.
Conclusion
Mandolins have double strings so that a stronger vibration can be created in order to amplify the sound and make it louder. The shape of your instrument and size and placement of the soundhole all play a part in amplification and resonance as well.
All of these factors together will contribute to how vibrational waves are formed and act inside the body of the instrument which ultimately determines the volume of sound produced.
