Once we have some basic information about a chord, such as whether it has scale degree 1/do or scale degree 7/ti in it, its bass note, and/or its quality, it can be helpful to arpeggiate the notes of the chord to figure out other details about it. Doing so can help us confirm via trial-and-error whether or not certain notes are indeed in the chord. It also helps us practice directing our attention around different parts of the texture. This arpeggiation can be sung or played on an instrument, though most people with a decent amount of voice control will probably find it easiest to do with their voice.
There is something a little unmusical about arpeggiating a chord to figure out its details. After all, chord progressions often exist in a state of continuous motion. Taking a moment to arpeggiate takes a chord out of its context and may require you to pause the actual music for a moment as you do so. Nevertheless, as you practice and get faster, you may be able to do these arpeggiations at a high enough speed to allow the music to continue; and even if not, using pieces of this skill occasionally (say, just arpeggiating certain chords or notes) can still be useful.
There are two obvious places to start this arpeggiation, depending on your other skills. If you can locate the bass note, this is probably the most logical place to begin the arpeggiation. You’re most likely to find a third above the bass, and then either a third or a fourth above that. On the other hand, if you find it more intuitive to locate scale degree 1/do or scale degree 7/ti with the Do/Ti Test, you may wish to start from there.
If starting from the bass, you should try arpeggiating the chord as if it is in “closed position”—that is, as if all the other chord tones were as close to the bass as possible. For example, if you hear an E3 in the bass, C4 in the tenor, G4 in the alto, and C5 in the soprano, you would arpeggiate up E-G-C.
If you find it more practical and intuitive to arpeggiate from scale degrees 1/do and 7/ti, you can find advice in the next section, on extensions to the Do/Ti Test.
Goal: Develop the ability to arpeggiate a heard chord.
Before you start: You’ll need a source of songs with chord progressions that are slow enough for you to sing arpeggios before they change. A series of exercises designed to facilitate such chord arpeggiation can be found at Cynthia Gonzales’s listen-sing.com, or you can use other music recordings.
Instructions: Listen to the music and choose a phrase, likely the opening phrase of the music. Start by finding the bass line as a reference point; make sure you can securely sing along to this line. Then restart the phrase and arpeggiate the chords up from the bass, in closed position, as best you can. If necessary, you can stop the recording at a difficult-to-figure chord, trying to retain it in memory, and arpeggiate through it by trial-and-error.