Teshuvah: Waking Up Through Sound
Sources about the practice and power of hearing the sounds of the shofar during Elul, the month leading up to Rosh Hashanah, and on Yom Teruah itself. Some of these sources can be found in Joey Weisenberg's book The Torah of Music with translations by Joshua Schwartz.
To immerse in the sounds of the High Holiday season and prepare to lead prayer services on Rosh Hashanah or Yom Kippur, visit Joey's site of master classes in Jewish song and join the 2023 High Holiday Leaders Haburah.
Scroll to the bottom of this sheet for a video explaining the basic halachot of Shofar blowing and links to additional related resources.
אַף עַל פִּי שֶׁתְּקִיעַת שׁוֹפָר בְּרֹאשׁ הַשָּׁנָה גְּזֵרַת הַכָּתוּב רֶמֶז יֵשׁ בּוֹ כְּלוֹמַר עוּרוּ יְשֵׁנִים מִשְּׁנַתְכֶם וְנִרְדָּמִים הָקִיצוּ מִתַּרְדֵּמַתְכֶם וְחַפְּשׂוּ בְּמַעֲשֵׂיכֶם וְחִזְרוּ בִּתְשׁוּבָה וְזִכְרוּ בּוֹרַאֲכֶם.
Even though [the reason] the shofar is blown on Rosh Hashanah is because of a biblical mandate, it still has a hint at some meaning, as if it says, “Wake up, you sleepers from your slumber, get up from your nap, nappers. Sift through your actions and return with repentance (teshuvah), remember your Creator.
The shofar is strongly associated with Rosh Hashanah, which was originally called Yom Teruah, the Day of Blasts. But the Rambam sees a deeper significance to the mitzvah — that its sound can jolt a person from even the deepest spiritual unconsciousness. For some of us, it takes more than a day or two to really emerge from this sort of sleep.

“Suddenly you are awakened by a strange noise, a noise that fills the full field of your consciousness and then splits into several jagged strands, shattering that field, shaking you awake. The ram's horn, the shofar, the same instrument that will sound on hundred times on Rosh Hashanah, the same sound that filled the world when the Torah was spoken into being on Mount Sinai, is being blown to call you to wakefulness. ... The horn blows to usher in Elul, and it is blown every morning of the month of Elul as well, lest we forget and slip back, lest we surrender to the entropic pull of mindlessness.”

—R. Alan Lew, This Is Real and Your Are Completely Unprepared: The Days of Awe as a Journey of Transformation, pp.64-65
The shofar's power is to open the gates of teshuvah. If we hear it enough times in Elul, the month leading up to Rosh Hashanah, the shofar may lead us to the entrance of our own path of return...
One of the customs of the month of Elul is sounding the shofar at the end of the morning prayer service, and there's even an echo of the shofar in another Elul practice, daily recitation of Psalm 27, which references זִבְחֵי תְרוּעָה, offerings accompanied by teruah, joyous shouting. (If you're looking for a melody for this text, try Aly Halpert's “Achat Sha'alti,” which is based on Psalm 27:4.) This rising sound is meant to wake us up as much as it is meant to stir supernal realm.
"בראש חודש אלול אמר הקב"ה למשה: עֲלֵה אֵלַי הָהָרָה (דברים י, א), והעבירו שופר בכל המחנה, שהרי משה עולה להר, שלא יטעו עוד אחר העבודה זרה. והקב"ה נתעלה אותו היום באותו שופר, שנאמר (תהלים מז, ו): עָלָה אֱלוֹקִים בִּתְרוּעָה ה׳ בְּקוֹל שׁוֹפָר. ועל כן התקינו חכמים שיהיו תוקעים בשופר בראש חודש אלול בכל שנה ושנה" (פרקי דר' אליעזר מו). ובחרו לעורר את העם על ידי קול השופר, מפני שיש בכוחו להזהיר את העם מלחטוא ולעורר את הרבים לעשות תשובה (טור וב"י או"ח תקפא, א).
On Rosh Ḥodesh Elul, God said to Moshe, “Come up to Me on the mountain” (Shemot 24:12). The shofar was then blown in the camp, to let it be known that Moshe was ascending the mountain again and that Israel must not repeat their mistake. God ascended on that day through those same shofar blasts, as we read, “God ascends with a blast (teru’a); the Lord, with the sound of a shofar” (Tehilim 47:6). Therefore, the Sages ordained that the shofar be blown each year on Rosh Ḥodesh Elul. (Pirkei De-Rabbi Eliezer 46)They chose to have the shofar serve as a wake-up call for the people, because it has the power to discourage people from sinning and to awaken the masses to repent (Tur and Beit Yosef, OḤ 581:1).
וְכַד אִתְּעַר הַאי שׁוֹפָר וְכַד בְּנֵי נָשָׁא תַּיְיבִין מֵחֲטָאֵיהוֹן, בַּעְיָין לְנַגְדָּא קוֹל שׁוֹפָר מִתַּתָּא, וְהַהוּא קָלָא סָלִיק לְעֵילָּא, כְּדֵין אִתְּעַר שׁוֹפָרָא אָחֳרָא עִלָּאָה, וְאִתְּעַר רַחֲמֵי, וְאִסְתַּלָּק דִּינָא. וּבָעֵינָן לְאַחֲזָאָה עוֹבָדָא בְּשׁוֹפָר, לְאִתְּעָרָא שׁוֹפָרָא אָחֳרָא, וּלְאַפָּקָא בְּהַאי שׁוֹפָר לְתַתָּא, אִינּוּן קַלֵי, לְאַחֲזָאָה דְּכָל אִינּוּן קָלִין דִּלְעֵילָּא, דִּכְלִילָן כֻּלְּהוּ בְּהַהוּא שׁוֹפָר עִלָּאָה, יִתְּעֲרוּן לְנָפְקָא.
When this shofar awakens and when people turn away from
their wrongdoings, we must sound the voice of the shofar below
(on earth). That voice of the shofar rises above in order that the
other shofar above awakens. And thus, Compassion awakens
and Judgment is removed.
This Zohar text and translation, as well as the poem fragment below, were found in Pedagogy of Partnership's source sheet “‘Reading’ the Shofar” from Hadar's High Holiday Reader for 5783.
it is a wonder
the shofar
is shaped
like the inside
of an ear
because at the moment
we are blasted with sound
and our whole world becomes the ancient voice,
longing
calling
demanding
we are meant to listen to whom is below noise...
—Devon Spier, “The Shape of the Shofar”
In the morning, when our minds are still waking up from the night's sleep, we sound the shofar in order to wake ourselves up. But it's not just our minds that need rousing. We are enjoined to listen with our hearts as well...
...וְכֵן מִי שֶׁהָיָה עוֹבֵר אֲחוֹרֵי בֵית הַכְּנֶסֶת, אוֹ שֶׁהָיָה בֵיתוֹ סָמוּךְ לְבֵית הַכְּנֶסֶת, וְשָׁמַע קוֹל שׁוֹפָר אוֹ קוֹל מְגִלָּה, אִם כִּוֵּן לִבּוֹ, יָצָא. וְאִם לָאו, לֹא יָצָא. אַף עַל פִּי שֶׁזֶּה שָׁמַע וְזֶה שָׁמַע, זֶה כִּוֵּן לִבּוֹ וְזֶה לֹא כִוֵּן לִבּוֹ:
And so it is with one who passes behind a synagogue or whose home is connected with a synagogue, and who hears the voice of the shofar or the voice of the megillah—if he directs his heart, he fulfills his obligation, but if he doesn’t direct his heart, he doesn’t fulfill his obligation. Even though this is listening and that is listening, one involves the directing of the heart, and the other doesn’t.

“The shofar speaks in a language that does not have words, is beyond words. ... More powerful than speech in its emotional intensity and impact, it is a mode of communication that bypasses the mind and enters straight into our hearts so that we feel its call viscerally with a different kind of knowing that we cannot explain or articulate.”

“The shofar is a cry inside each of us that needs to be let out.”

With enough practice in Elul, surely we will know how to fulfill the mitzvah of hearing the voice of return.
Shofar Blowing Basics