The landscape that gave birth to the modern Turkish cymbal (that is, discs with domed cups in the center made of various alloys, mostly bronze) was the Ottoman Empire, an Islamic sultanate that ruled the Middle East, the Balkans, and Northern Africa.
The capital of this empire was Istanbul, or as the Romans called it, Constantinople (named after one of the many emperors that the Roman Empire saw in its lifetime). The city, in its time as Constantinople, was part of the remnants of the Roman Empire, and was in turn the capital of yet another empire that preceded the Ottomans, the Byzantine Empire. This is why Meinl named their popular cymbal line 'Byzance', because of its roots founded in Turkish cymbal making.
Now that that's out there, here's how you pronounce 'Byzantine':
Therefore, the name of the cymbal line is pronounced as such:
-Insert witty comment here-