Does one fulfill the custom of hearing Shofar in Elul through hearing a live blowing taking place via Zoom and the like?
One is obligated to hear the original Shofar sound in order to fulfill his Mitzvah on Rosh Hashanah, and it does not suffice to hear an echoed sound that results from the original Shofar sound. The question is thus asked regarding a) Is the hearing of the sound of the Shofar through a live hookup [i.e. zoom] defined as the original sound, and if not then b) is there greater room for leniency regarding the blowing during Elul.
Background on fulfilling Mitzvos through live hookup: Initially, although there were some Poskim who understood that one may fulfill a Mitzvah through hearing it on a radio, telephone, microphone or broadcast system, practically after further research into the understanding of how these systems work, the Poskim conclude that this may not be done. Thus, one cannot be Yotzei the Mitzvah of Megillah reading, Havdalah, or the Rosh Hoshanah Shofar blowing, through hearing it through a broadcast, radio, telephone, or live hookup [even if it was left on before Yom Tov]. The question, however, is asked regarding the Shofar blowing of Elul, which is a mere custom, as to whether there is room for leniency, as will be explained next.
There are several reasons recorded behind the reason for blowing Shofar in Elul, the main reason being in order to arouse people in repentance. Seemingly, based on this reason, one can likewise fulfill his obligation of the custom through hearing the Shofar via a live hookup, as psychologically it can arouse the person in repentance. Furthermore, we rule that by Shofar sounds that are blown due to custom, as opposed to an actual Biblical or Rabbinical obligation, are valid even if an invalidating mistake was made in their blowing, and there is no need to repeat them. Furthermore, many Poskim argue that in truth there exists no obligation even due to custom for one who is without a Minyan to hear Shofar, and hence the entire discussion of being Yotzei through a live hookup is superfluous, as they are not obligated in it to begin with. Accordingly, it would seem that there is no issue with hearing Shofar through Zoom, or other live hookup, as a) he is not obligated to hear it, b) an invalid blow is valid for the customary blows of Elul, and c) it fulfills the purpose of arousing him in Teshuvah. Despite the above arguments, the Rebbe in a talk discussing being Yotzei Mitzvos through a tape and the like stated that even the blowing of Shofar in Elul which its sole purpose is to arouse one in Teshuvah, one should not hear through a tape and the like. The reason for this is because in order to properly arouse one in Teshuvah, he must hear the original sound that comes from the heart of a Jew, and not an electronic echo of it. Accordingly, for those who are unable to join a Minyan during Elul [i.e. quarantine etc] it is proper for all those capable to place effort to purchase their own Shofar and learn how to blow it, in order to be able to blow Shofar throughout Elul in its most Mehudar form. However, those who are unable to do so, are encouraged at the very least to hear it through alive hookup so they at least receive the psychological effect that it can have in them to do Teshuvah.
One should not initially be Yotzei the Minhag of blowing Shofar in Elul with a live hookup of the blowing. Thus, if one is capable, he should endeavor to purchase his own Shofar and learn to blow it, or simply join a Minyan which blows. One who is unable to do either, should endeavor to at least try to hear a live hook up of the blowing. Whatever the case, all the above is a mere Hiddur Mitzvah to fulfill the custom, as from the letter of the law one is not obligated to hear Shofar at all when he is without a Minyan.
 Admur 587:1; Michaber 587:1; Gemara R”H 27b; Piskeiy Teshuvos 589:3
 Minchas Elazar 2:72; Rav Pesach Tzevi Frank in Mikraei Kodesh 11 based on Halachos Ketanos 2:45; Hearos on Halachos Ketanos 276; Possibility entertained by Igros Moshe 2:108; 4:126 regarding Bedieved or time of need [See there that his leaning opinion is to permit being Yotzei and that so should be done in a case of need, that one is unable to hear Havdala or Megillah otherwise, and that perhaps one is not to protest one who is lenient, although he concludes to protest being that the allowance is unclear]; Tzitz Eliezer 8:11-10 regarding Bedieved or time of need; Sheivet Halevi 5:84 that from the letter of the law seemingly one is Yotzei [Rav Yaakov Meir Shtern claimed that the Shevet Halevi was indeed lenient to rely on this Bedieved ]; Opinion of Rav Shteinman quoted in Vayishma Moshe Gilyon 23
The opinion of the Chazon Ish: Chazon Ish, brought by Rav SZ”A in footnote in Minchas Shlomo 1:9, replied to Rav SZ”A with an argument to be lenient to validate if one heard a Mitzvah from a microphone, radio and the like, although Rav SZ”A concluded that he does not understand his argument; Practically, Rav Chaim Kanievsky stated that the Chazon Ish was not lenient to permit hearing Megillah from a microphone and even Bedieved one is required to re-hear it
 The reason for the allowance: As perhaps the above machines send the actual voice of the reader to the ears of the listener. [Igros Moshe ibid] Furthermore, even if the transmitted voice is not the natural voice of the reader, perhaps there is no need to hear the actual voice so long as the voice that one hears is the direct result of the actual voice and is heard at the same time as his natural voice. Furthermore, perhaps all hearing is through the sounds being reproduced in the air until it reaches the ear of the listener, and nonetheless one is Yotzei. [Arguments of Chazon Ish ibid; Igros Moshe ibid; Shevet Halevi ibid; Mikraeiy Kodesh ibid that so is proven from Halachos Ketanos ibid who permits mechanical hearing aids as carrying a sound through a secondary means is valid]
 Daas Torah 689 based on Halachos Ketanos; Mahraiy Engel Brachos 25; Rav SZ”A in Minchas Shlomo 1:9 “One cannot be Yotzei anything from a microphone and speakers or the radio and telephone, and those who puzzle at this ruling simply do not understand the mechanics of these machines, thinking erroneously that there is some kind of magical transportation of the persons actual voice. I have lengthened in this Teshuvah to negate this mistake, as they do not know the truth, and I have spoken with people knowledgeable of this matter, and they all agree with me.”; Eretz Tzvi 1:23; Mishpitei Uziel 1:5; Final ruling of Chazon Ish, as brought in previous footnotes; Minchas Yitzchak 1:37 and 3:38; Yechaveh Daas 2:68; 3:54; Chazon Ovadia Megillah 56; Mishneh Halachos 4:85; Kinyan Torah 1:75; Beir Moshe 3:166-168; Piskeiy Teshuvos 689:3; Rebbe in Igros Kodesh 23:304 and Likkutei Sichos 21:496, printed in Shulchan Menachem 3:319,“What is heard is not a man’s voice at all (and does not even resemble the case of one who sounds a Shofar in a pit). It is obviously most novel, even strange, to suggest that an indirect effect (koach kocho) and a basic transformation of the very nature of speech, should serve as a substitute for speech. Even though the recent scholars who have ruled otherwise include reputed poskim, it is evident from their very responsa that those who explained them the nature and workings of the telephone made a basic mistake.”; Rav Yaakov Yosef Z”l completely invalidates using it, and states the Poskim who permitted made a mistake in their understanding of these systems; The following lenient Poskim all agree that one is initially to be stringent: Igros Moshe 2:108; 4:126; Tzitz Eliezer 8:11; Sheivet Halevi 5:84 that it is forbidden to hear from the above systems even though it is possible that one is Yotzei
Other opinions who rule that despite the new and confirmed knowledge of the system one can be Yotzei: Some of the lenient Poskim ibid rule that despite the confirmed understanding of the mechanics of the above machines and that the sound is not the natural voice, nevertheless one is still Yotzei, or is at least questionably Yotzei the Mitzvah, as perhaps there is no need to hear the actual voice so long as the voice that one hears is the direct result of the actual voice and is heard at the same time as his natural voice. [See Chazon Ish ibid; Igros Moshe ibid; Mikraeiy Kodesh ibid; Tzitz Eliezer ibid]
 The reason: As one must hear the readers voice to be Yotzei the Mitzvah [Admur 124:11], and this voice must be the persons natural voice [See Admur 587:1; Michaber 587:1; Gemara R”H 27b where echoes are invalidated for Shofar hearing] and one is thus not Yotzei the Mitzvah if he hears an artificial mimic of the readers voice. Now, being that the above technologies do not magically send the natural voice of the reader to a further distance but simply make an artificial mimicking of it, therefore one cannot be Yotzei the Mitzvah through hearing the Megillah through a broadcast, radio, telephone, or live hookup. Just as one cannot be Yotzei a Mitzvah by playing a recording of the Mitzvah, as one is not presently hearing the voice of one who is obligated in the Mitzvah, but rather of a machine which contains no obligation, so too one cannot be Yotzei even if the event is live, as in both cases it is a machine made voice being sounded, and machines are not obligated in Mitzvos. [Rav SZ”A ibid; Rebbe ibid] This is in addition to the fact that some Poskim rule that it is forbidden to ever answer Amen through a distanced transmission being that there are churches and bathrooms in the interim area where the voice travels. [See Piskeiy Teshuvah 167; Rav SZ”A in Minchas Shlomo 9:1; Moadim Uzmanim 6:105; Mishpitei Uziel 1:5 [brought in Igros Kodesh 13:221 as opinion of Sefaradim]; Beir Moshe 3:166-168]
 Rebbe in Sichas Balak 7th Tammuz 1984
 Tur 581; Kitzur SHU”A 128:2
 Admur 590:19 regarding blows of after Musaf
 Tzitz Eliezer 12:48; Rivivos Efraim 1:394 in name of Rav Chaim Kanievsky and many other Rabbanim who he corresponded with; Piskeiy Teshuvos 581:3
Other opinions: Some Poskim rule that one is to blow the Shofar even when praying in private [Siach Yitzchak 264; Nitei Gavriel 4:9 and footnote 14 in new edition versus old edition in which he wrote not to blow]
 Sichas Balak 7th Tammuz 1984 “Even the sounding of the Shofar in Elul, which is only to arouse Teshuvah, is not to be heard from a recorder as since it needs to arouse ones feelings of Teshuvah therefore it has to be done through a person, as words that come from the heart enter the heart”