Aulos

I really like double instruments. They have smaller scale but their sounds becomes much better. Well it doesn't work if second pipe just give one constant sound like in bagpipes.

Some information from Wikipedia:

An aulos was an ancient Greek wind instrument, depicted often in art and also attested by archaeology.

There were several kinds of aulos. A single pipe without a reed was called the monaulos. A single pipe held horizontally, as the modern flute, was the plagiaulos. The most common variety must have been a reed instrument. Archeological finds, surviving iconography and other evidence indicate that it was usually double-reeded, like an oboe, although simple variants with a single clarinet-type reed cannot be ruled out.

Though aulos is often and erroneously translated as "flute", its sound — described as "penetrating, insisting and exciting" — was more akin to that of the bagpipes, with a chanter and (modulated) drone. Like the Great Highland Bagpipe, the aulos might be used for martial music, but it is more frequently depicted in other social settings. It accompanied physical activities such as wrestling matches, the broad jump, the discus throw and to mark the rowing cadence on triremes, as well as sacrifices and dramas.

It appears that some variants of the instrument were loud, shrill, and therefore very hard to blow. A leather strap, called a phorbeiá in Greek or capistrum in Latin, was worn by the auletai to avoid excessive strain on the lips and cheeks due to continuous blowing. Aulus players are sometimes depicted with puffed cheeks. The playing technique almost certainly made use of circular breathing, very much like the Sardinian launeddas which would give the aulos a continuous sound.

How it looks:


Example of playing: