Pure Ocarinas focuses on instruments with 10 or 11 holes, as we believe they make better musical instruments, with considerable benifits for a player:
And dont worry, the 10 and 11 hole design has almost identical fingering, the only differance is the subholes.
If you want a larger sounding range, id strongly reccomend getting a multichamber ocarina instead of a 12 hole, as they can extend the range of an ocarina working in harmoney with its limited physics:
For example, a double alto G ocarina gives you the low B and A of a 12 hole alto c ocarina, plus a low G. All of these notes play with clean strong sound, and with no need for irregular breath cuts.
It is true that improvements have been made over time which have improved the behaviour of the 12 hole ocarina, but ocarinas are lossy:
Regardless of how good a 12 hole ocarina is, the same design with fewer holes will result in a better instrument.
Ocarinas function by creating a preassure differential between the environment and an enclosed chamber, opening holes raises the pitch as it allows the air to move more easily, but this also allows air to escape. You can only have so many holes before the instrument stops sounding.
The 12 hole ocarina exists right on the limit of what is physically attainable, and making it work largely dictates the design of the entire instrument, and leaves a maker with little freedom.
The two subholes of a 12 hole ocarina also change the playing characteristics of the entire instrument, giving it a steeper preassure curve, increasing the preassure differance between the high and low notes, and almost doubles the size of the finger holes. Changes which make the instrument harder to play.
Multichamber ocarinas do not suffer from these problems as they have different chambers whose size matches the range of notes produced. They work in harmoney with the instrument's physics instead of against it. The size of each chamber is chosen to produce the best possible sound, and the smaller range means that the chambers generally sound better.
The first chamber, even with two subholes, still has a smaller range than a 12 hole single chamber having no right thumb hole. Eliminating the right thumb hole has other benifits as it generally improves the instrument's ergonomics.