Listen for rest rather than position
The first chord of a song is not necessarily its home chord. Listen to several phrase endings and notice which harmony feels like a stable place to stop. Hum the note that seems most settled at those moments and find it on an instrument. This gives you a candidate tonal center, not immediate proof. Some songs delay resolution, move between tonal areas, or use repeating loops that leave the center open to interpretation. Keep your first guess flexible until more of the piece supports it.
Test a candidate against the melody
Play the suspected home chord beneath a phrase ending and listen to the melody's final sustained note. Then compare another plausible chord from the progression. Which version supports a sense of arrival, and which feels as though it needs to continue? Use a quiet, simple voicing so the comparison is not dominated by register or loudness. Try the test at more than one point in the song. A single local cadence can suggest a temporary destination without establishing the tonal center of the complete arrangement.
An opening chord that is not home
Try this original four-bar phrase in C major: F for one bar, G for one bar, C for one bar, then C again. Use four beats per bar. Sing A for the first bar, B for the second, and C across the final two. The first chord is F, yet the movement B to C and the sustained closing C make C a strong candidate for home. Stop after the first bar, then after the last, and compare the different sense of completion.
Now change only the final chord to Am while keeping the melody's final C. C belongs to both C major and A minor, so the melody note alone cannot settle the question. Repeat both endings, with the preceding F and G included, and listen to the bass destination. Write two columns in a notebook: evidence for C and evidence for Am. Add actual observations such as repeated final bass C, rather than broad statements such as happier sound. A chord's membership in the scale is weaker evidence than the way a complete phrase directs attention toward it.
Use the result as a working map
Once a likely center emerges, describe nearby chords in relation to it and see whether the relationships help you hear the progression. Compare the map with your AudioChords chart, checking surprising labels by ear. Do not rewrite an unusual chord merely because it falls outside the most familiar scale. Borrowed harmony and modulation are musical possibilities, not automatic errors. If the center remains ambiguous, you can still learn the chord sequence and form accurately. Tonal understanding is useful when it clarifies what you hear; it should not become a demand to force every song into a simple answer before you can play it.
When the evidence disagrees
Apply this test to three locations in your song: one verse ending, one chorus ending, and the last clear arrival. Agreement makes a working interpretation stronger; disagreement may reveal a local destination or a deliberately open loop. Avoid pressing a home chord over every moment and calling any clash disproof: a tonic is not an accompaniment for every other harmony. If you can play the progression but cannot establish one convincing center, retain the chord names and mark the key uncertain. That is a usable rehearsal result, not a failed analysis.