The following essay uses parallel order structure throughout. Notice how paragraph "B1" considers the same attributes as "A1" in the same corresponding order. Both discuss the shape of the instruments, the sound holes, the number of strings, the quality of the sound produced, etc. in the same sequence. This makes it easy for the reader to absorb. Notice too that when the writer discusses the characteristics of "thing B" she contrasts them with "thing A" (ex. "Unlike the balanced sound of the teardrop dulcimer, the treble sound in the hourglass dulcimer is much more prominent than its bass sound"). The main purpose of the comparison essay, after all, is not just listing the separate characteristics of each thing, but contrasting them with each other.
A COMPARISON BETWEEN TWO APPALACHIAN DULCIMERS
Late in the 17th century, the early settlers in the Appalachian mountains created an instrument which combined the sounds of the bagpipes and the harpsichord: the Appalachian dulcimer. This beautiful instrument was brought down from the mountains during the folk music revival of the sixties and since then has been steadily increasing in popularity. Two varieties have become widely used by North American folk musicians: the tear drop dulcimer and the hourglass dulcimer. These two types of dulcimers differ in their physical characteristics, their sound, and in the way they are played.
The shape of the teardrop dulcimer allows it to produce a full, strong sound. As its name implies, it is shaped like a teardrop and it has either one large central sound hole or two smaller ones. It can have from three to six strings which can be tuned in any key. The sound box of the teardrop dulcimer is usually two to four inches in depth and the sound it produces is strong and loud. Because of the round shape of the instrument, its sound is a rich balance of the bass and treble modulations.
The way in which the teardrop dulcimer is held when being played allows the musician to play a variety of styles of music. It is held flat against the chest like a guitar, with the left hand pressing the strings down on the fretboard while the right hand strums or picks all of the strings to produce a droning sound. The music created using this method is simple and is usually used to accompany a voice or other instruments. In the modern method, the left hand plays all the strings in newly developed chord patterns while the right hand can strum or pick a melody. This method allows the musician to play complex music in styles ranging from classical to rock and roll. Using the modern method, the teardrop dulcimer can be played as accompaniment or as a solo instrument.
The hourglass dulcimer, because of its unique shape, produces a soft, gentle sound. It is shaped like an hourglass with the top half (which is nearest to the tuning pegs) being smaller than the bottom half. There are two small sound holes on each half of the instrument. Like the teardrop dulcimer, it can have from three to six strings. The sound box of the hourglass dulcimer is usually one to two inches deep; therefore, its sound is much softer than that of the teardrop dulcimer which has a deeper sound box. Because of the narrow channel between the two halves of the hourglass dulcimer, the bass and treble modulations are separated to produce a stereo effect. Unlike the balanced sound of the teardrop dulcimer, the treble sound in the hourglass dulcimer is much more prominent than its bass sound.
The position in which the hourglass dulcimer is played limits its versatility as an instrument. It is usually placed flat across the player's lap with the tuning pegs on the left. Although you can play it like a guitar this would be difficult since it does not have a narrow neck like the teardrop dulcimer and it would be strenuous for the player to extend his arm around the box to play it. Therefore, the "guitar position" is seldom used. The traditional method of playing dulcimers is used most often on the hourglass dulcimer using a small wooden dowel, held by the left hand, to play the melody string. The new method of playing is used by some musicians but chording is difficult when the instrument is lying flat across the knees. Because of its soft sound and its shape the hourglass dulcimer is less versatile than the teardrop dulcimer and is best suited to play traditional simple folk music accompanying a singer or soft sounding instruments like the guitar or mandolin.