* The Tsar's Bride 174—Sopr. and Mezzo-sopr.

* Tsar Saltan 5-6—Sopr. and Mezzo-sopr.

In the case of voices related in twelfths:

12[Sopr.
Bass,

intervals approaching one another do not create a good effect, for this transplants the deeper voice into the upper register and vice versa. Singing in unison is no longer possible, and thirds are to be avoided; the use of sixths, tenths and thirteenths is recommended. The voices will often be separated by more than a twelfth and crossing of parts is out of the question.

Example:

* Tsar Saltan 254-255.

Relationship in tenths

10[Sopr.orM.-sopr.
Bar.Bass

is fairly common. The explanations given above are also applicable in this case.