It's easy to see why you'd be confused... this article explains what the growth pattern of a violin is like:
http://www.ask.com/wiki/Violin_family?qsrc=3044
But even a Double Bass is only middlin' large... then there's the Giant Violin:
http://www.mi-pro.co.uk/news/read/look-everyone-a-giant-violin/016269?oo=41647999
The violin, a project by 15 violin makers from the town of Markneukirchen in Saxony, has a height of 4.27 metres and a bow 5.22 metres long. Based on an old Vogtland model, it is seven times as big as a conventional violin. it takes three musicians to produce a sound.
However, they can grow to even larger proportions...
http://www.neatorama.com/2007/09/21/building-looks-like-giant-piano-and-violin/
So, how large is a Titanic Violin???