The Shulchan Aruch rules that we should blow TaShRat three times after Malchios, TaShaT three times after Zichronos and TaRaT three times after Shofaros. Due to the issues involved, he requires 30 sounds for the Tekiyos Demeumad and pushes aside the concern of burdening the community.
The Ram”o, recording the custom in Ashkenaz, rules like Rabbeinu Tam. The Ta”z explains that we rule like Rabbeinu Tam and not like the Rif, because it is preferable to ‘fix’ the concern of the sounds being contradictory than the concern of a Hefsek.
In the Shulchan Aruch, the Alter Rebbe writes that the Minhag (like the Ram”o) is to follow Rabbeinu Tam. He also notes those whose custom is to follow the opinion of the Rif as well as the opinion of the Mechaber.
He concludes by bringing a different opinion which he writes is the most preferable of all. This is to blow the 10 notes of TaShRat, TaShaT and TaRaT after each of the three Brachos, making up 30 notes in the Tekiyos Demeumad as well.
Since we have been Yotzai already in the earlier Tekiyos, we do not concern ourselves with the issue of a Hefsek in the repetition.
The Rambam and Rav Hai Gaon
All of the above is according to the view of the Rambam, that the reason why we blow 30 sounds for the Tekiyos Demeyushav is because of a three-way doubt as to the correct sound of the Teruah. We blow 30 sounds to cover all three possibilities.
According to the view of Rav Hai Gaon, all forms of the Teruah are Biblically valid and we only blow all combinations to ensure that all Jewish communities follow a uniform practice. Based on this, by blowing TaShRat once after Malchios, TaShaT once after Zichronos and TaRaT once after Shofaros, we do fulfil the required number of Tekiyos. Further, by blowing each of the three combinations only once for the Tekiyos Demeumad, we highlight that one is Biblically Yotzai according to all opinions.
Based on this, we can conclude that the Rif, who is not bothered by the ‘contradiction’ of combining the different combinations, follows the view of Rav Hai Gaon.
