The New Adolescent Bass
There is a dramatic type change which occurs occasionally with some boys.  At the beginning of the year directors occasionally encounter a young man whose voice appears to have gone completely from boy treble to adolescent bass during the summer (in a period of three months or less).  The bottom drops out, so to speak.  This young man can sing and E or F below the bass clef, but his upper voice seems to be locked around F, fourth line, bass clef, refusing to move upward.  It is not unusual for him to have a nice falsetto (head voice) when he is asked to sing any falsetto above G (second line, treble clef), but there is this terrific gap, possibly as wide as an octave from F above to the F below middle C.
 
This vocal syndrome is mostly genetic in origin, but it is often exacerbated if he is an inexperienced singer.  He may have engaged in the singing process very little as a boy treble, joining mid-level choir at the insistence of a friend or because the choir contains good-looking girls.  None-the-less, he is an obvious presence and it is the director's obligation to teach him.

As said previously, usually this syndrome occurs with boys whose vocal maturation is fast; however, this the good part!  He should begin to add the upper notes one at a time rather quickly.  One must simply be patient.  In the meantime, consider the following: Keep him singing the comfortable notes in his range which are usually around the F octave (fourth line, bass clef) down to the low F (below the bass clef). Vocal rest only extends the maturation process.

At cadence points when the baritone part is written soh down doh, teach this young man to sing the soh an octave lower (he will sing soh up to doh). When, at cadence points, the baritone part is written soh up to doh, teach him to sing doh an octave lower (he will sing soh down to doh).

Most importantly, when the baritone part moves above the F (fourth line, bass clef) pencil in some optional notes that are in the F-F octave that is comfortable for him.  Sometimes, writing those notes in the part an octave lower will work and it sounds okay, for the most part.  If this doesn't work, pencil in a different note in the chord for him to sing that is in his range.

Finally, read chapter ten in the text, Teaching Choral Music, 2nd edition (Prentice Hall, 1999) entitled Proper Vocal Technique for Adolescent Voices (pages 184-204).  This book is available through your favorite bookstore or music dealer, or a copy may be found in the local library.  To obtain a more indepth understanding of the book's contents and reviews, they may be accessed at http://vig.prenhall.com/catalog/academic/product/1,4096,0130813567.html,00.html.  Establishing good breath control and resonance will be most helpful for this young man at this point in his maturation process.  Also, good vocal technique will be helpful for all choir members in freeing their voices in the upper areas of their comfortable singing ranges (it is best not to attempt to extend the boys ranges during the height of the mutation process, just keep them singing comfortably until they get through that stage of their maturation.) It is okay with the girls at this age, with limits.

Passing upwardly through the passaggio (from chest voice into head voice, or falsetto) is very difficult, if not impossible, for him. The "blank spot" around middle C is manifested because the vocal folds will not come together (due to the fast growth) in chest phonation resulting in a very wide passaggio (passage) which is very difficult to negotiate. That is why it is important to keep him singing in chest phonation where it is comfortable. Asking him to move from chest phonation into falsetto usually results in the voice breaking or cracking.  Once a boy enters vocal mutation, it is not recommend to vocalize them in falsetto phonation until their voices have begun to settle after maturation which may be as late as their junior year in high school with some boys.  In other words, for these boys who are experiencing the more dramatic type change, the technique of beginning an exercise in falsetto and singing downwardly through the passaggio is only helpful after the voices have settled.  Exercises beginning in falsetto should only be used early on with boys whose voices change smoothly and move gradually downwardly (and who experience minimal cracking and breaking), and many directors do not use it at all with mid-level students.

Remember, usually this dynamic type change occurs quickly, so it should be a consolation that within a couple/three months, with good vocal technique, those upper notes will return to his voice -- just be patient and keep him singing comfortably.  It may be a good idea to share these thoughts with him.  He needs to know that what is happening to him is quite normal with some boys, and that his future as a singer is bright!