1,159. The Duration of Shofar Blasts

Hilchos Shofar, Succah v’Lulav 3:4

A teruah must be as long in duration as two tekios; three shevarim must be as long as a teruah. If someone blows a tekiah and a teruah, followed by a long tekiah, which he extends so that it is twice as long as the first tekiah, we do not say that it may be considered two tekios, which would enable him to finish by blowing a teruah and another tekiah. Rather, even if one blew a tekiah that lasted all day long, it would still only count as one tekiah, requiring him to blow another tekiah, teruah and tekiah.

Hilchos Shofar, Succah v’Lulav 3:5

If a person heard one shofar blast and he heard a second one an hour later, they may be considered a single unit in order to fulfill one’s obligation. This is so even if it takes all day, though it only applies so long as each set of shofar blasts is heard in the proper sequence. If one hears a teruah followed by two tekios, two tekios followed by a teruah, or any other variation, it is ineffective.