Among the musical modes (scales) used in the Ashkenazic tradition for publicly reciting sections of TaNaCH, that of reading Megillat Esther on Purim stands alone. It’s unused at any other time.
What’s a “mode?” It’s a specific choice of notes from which melodies are created. Sort of like a “scale” (remember “do-re-mi-fa-sol-la-ti-do”?). For those of you who have read a parshah from Torah or a haftarah in Synagogue, you know that the musical signs (trop) are the same, but the melodies associated with them differ (Megillat Esther likewise has the trop signs, but its own “melodies”). The differences are what make up a “mode.” In Western music, there are basically two scales — “Major” and “Minor.” An example of a “Major” scale would be “The Star Spangled Banner.” An example of a “Minor” scale would be “Hatikvah.” But in other, non-Western (European) musical systems — like the various Jewish traditions; Arabic classical music; Indian classical music — there can be many more than these two scales or modes.
Typically, when a particular mode is used — in reading Torah, for example — it’s used all the way through.
But within the reading of “Esther,” there are some interesting insertions. A.W. Binder refers to them as musical “detours” in his book, “Biblical Chant.”
The first comes at verse 1:7. The text says that at his feast, Ahashverosh gave drink to his guests in vessels of gold.
Midrash Esther 2:11 says that these golden vessels had been taken from the First Temple in Jerusalem at its destruction.
It’s a terrible image: vessels that had been sanctified, that had for centuries been used only for the holy purpose of bringing the world closer to G-d, had been carried off wantonly and were now being used to drink wine at a rowdy, drunken feast. Vessels that had been used in orderly silence were now being used in noisy chaos.
That destruction is recounted on Tisha b’Av by reading “Eichah” (“Lamentations”) with its own unique, sad-sounding mode.
The destruction of the Temple being a sad memory, the “Eichah” mode is applied to the reading of the words “v’keilim mikeilim shonim” — “and the vessels…” — after which the regular “Esther” mode is resumed. “Detours” to this same “Eichah” mode appear again at verses 2:6, 3:15, 4:1, 4:16, and 7:3.
In Binder’s “Biblical Chant,” he gives a musical direction that these “detours” are to be recited “sadly.” When I’ve read the Megillah in synagogue, I’ve slowed down slightly on these words. But not too slowly and not for too long. Despite the midrash and the musical directions, the truth is — the “audience” is usually in too-high spirits to pay such close attention or take anything too seriously.
Another example is on verse 7:10 — “They hanged Haman…,” for which Binder’s musical direction is “Energico.” Elsewhere, he tells us that this should be sung in a “joyous and exalted style” — not with the “Eichah” mode, of course.
We’re not rejoicing at Haman’s death per se. Elsewhere, we were taught not to cheer the death of the Egyptian army pursuing the exiting Israelites at the Reed Sea. So, kal v’homer…
But we might rejoice at the relief from feelings of distress. Or, we might rejoice at the display of G-d’s “hashgachah protis” (Divine Providence), in which case we’re rejoicing in praise of G-d.
In any case, it’s another musical “detour” from the straight use of the “Esther” mode alone.
These “detours” and “variations” might best be appreciated by listening to a recording of the Megillah in advance of Purim itself. It can be heard (at a 25% reduction in tempo, to make it easier for learning) at:
As with other holidays, the preparation can begin long before the actual event. 
 Rabbi Chaim Weiner also shared the following with me:
Here is a short article I wrote for our shul newsletter several years back, that gives a full list of the special melodies used in the Megillah.
What Should We Look Out for this Year When Listening to the Megillah Reading?
Purim is the most frivolous holiday in the Jewish year, a time when pranks and tricks, disguises and costumes, not to mention drink, are acceptable and appreciated. It therefore should not come as a surprise that some of this frivolity also carries over to the actual reading of the Megillah itself. The Megillah reading, unlike reading from the Torah or the prophets is not a straight forward thing. There are many “tricks” used to enhance the reading, and to make it more fun. Here are some to look our for:
There are four “key” verses in the Megillah, known as the verses of redemption. These verses actually tell the whole story of Purim, and are the minimum that one has to read from a Megillah, to be considered to have read the story of Purim. These verses are: 2:5; 8:15; 8:16; and 10:3. The reader stops before reading each of these verses and the whole congregation reads them together before being repeated by the reader.
Seven verses, which recount times of sorrow, are read using the melody used for the book of Lamentations. These verses are 1:6; 2:6; 3:15; 4:2; 4:3; 4:16; and 8:6. The skill of a reader is measured by one’s ability to change from one set of notes to the other without being confused.
Five additional verses are read as proclamations. These should sound like a town crier. These verses are 4:14; 6:9; 6:11; 7:5; and 7:6. In addition four other verses are read with a melody reminiscent of the kind of music we would hear from our television screens signifying a lurking danger or impending doom. These verses are 2:4; 2:17; 8:14 and 10:2.
Finally, four verses with their own special tunes. Verse 1:22 “That each man shall wield authority in his home” is read with a “royal” motif. Verse 6:1 “On that night, sleep deserted the king …” is read with the same tune as “Hamelech” from the high holidays. Verse 10:3 “For Mordecai the Jew ranked next to King Ahasuerus … ” is read with the tune of “Adir Hu” from the Seder. Finally, verse 7:10 “So they impaled Haman on the stake which he had put up for Mordecai …” is read in glee.
It is not unheard of for a Megillah reader to read women’s voices in a high pitch voice. I have also seen readers stand with a collection of hats, and wear the right one for each speaker in the Megillah.
Music is as much part of our tradition as anything else. For person growing up in the tradition, tunes and melodies carry with them connotations and special meanings. The art of reading the Megillah is to weave these connotations together into a frivolous but clever presentation of Megillah. Pay attention this year, and see what you find.