אורח חיים תקפ״חOrach Chayim 588

Se’if 1א׳

זְמַן תְּקִיעַת שׁוֹפָר בַּיּוֹם וְלֹא בַּלַּיְלָה; וּמִצְוָתָהּ מִשְּׁעַת הָנֵץ הַחַמָּה וָאֵילָךְ, וְאִם תָּקַע מִשֶּׁעָלָה עַמּוּד הַשַּׁחַר יָצָא. וְאִם שָׁמַע מִקְצָת תְּקִיעָה קֹדֶם שֶׁעָלָה עַמּוּד הַשַּׁחַר, וּמִקְצָתָהּ אַחַר שֶׁעָלָה עַמּוּד הַשַּׁחַר, לֹא יָצָא. הַגָּה: וְאִם הָיָה שִׁעוּר תְּקִיעָה בְּמַה שֶּׁשָּׁמַע בַּיּוֹם, נִתְבָּאֵר בְּסִימָן תקפ"ז סָעִיף ג'.

Time for sounding the shofar, and regarding this there are 5 paragraphs. The time to sound the shofar is during the day, and not at night. The mitzvah is [binding] from the sunrise [netz hachamah, the sun is visible in the horizon] onwards. And if one sounded since dawn [when the sun has began to illuminate but is not yet visible] one has fulfilled the obligation. However, if one heard the shofar being sounded partly before dawn and partly after dawn, one has not fulfilled one's obligation. Rema: And if there was the shiur (minimal halachic amount) of tekiah blasts in that what he heard in the day, see what was explained in Siman 597 Paragraph 3.

Se’if 2ב׳

שָׁמַע ט' תְּקִיעוֹת בְּט' שָׁעוֹת בַּיּוֹם, יָצָא וַאֲפִלּוּ הֵם מִט' בְּנֵי אָדָם תְּקִיעָה מִזֶּה וּתְרוּעָה מִזֶּה וּתְקִיעָה מִזֶּה; וְיֵשׁ אוֹמְרִים דְּדַוְקָא בְּשֶׁלֹּא הִפְסִיק בֵּינֵיהֶם בְּקוֹל שׁוֹפָר שֶׁאֵינוֹ רָאוּי בְּאוֹתָהּ בָּבָא.

If one heard 9 teki'ot during 9 hours in the day, one has fulfilled one's obligation. And this is true even if there were 9 different people [blowing], and one heard a teki'ah from one, and a tru'ah from another, and a teki'ah from another, one has fulfilled. And some say specifically when there was not a break between them with a sound of the shofar that was not fit for that set (of blasts).

Se’if 3ג׳

שָׁמַע ט' תְּקִיעוֹת מִט' בְּנֵי אָדָם שֶׁתָּקְעוּ כֻּלָּם כְּאֶחָד, לֹא יָצָא, שֶׁאֵין כָּאן פְּשׁוּטָה לְפָנֶיהָ וּפְשׁוּטָה לְאַחֲרֶיהָ. הַגָּה: וְאִם שְׁנַיִם תָּקְעוּ כְּאֶחָד כָּל הַסֵּדֶר, וַאֲפִלּוּ אֶחָד תָּקַע בַּחֲצוֹצְרוֹת, יָצָא דְּיָהִיב דַּעְתֵּיהּ עַל הַשּׁוֹפָר (הַגָּהוֹת אֲשֵׁרִי וּגְמָרָא פ' רָאוּהוּ בֵּית דִּין).

3. If one hears 9 teki'ot from 9 different people which were sounding the shofar at the same time, one has not fulfilled one's obligation, since there is no simple sound before and after it. Rema: And if two are sounding as one all the order (of blasts), even if one is sounding with a biblical trumpet, one has fulfilled one's obligation as long as one's attention is turned to the shofar.