Can I move MobileSync to a hard disk other than startup volume?

Question

I have been told many times by others 'in the know' that you have to keep certain files on the start-up volume. However, I have 2 internal HDs on my iMac, and the SSD (start up volume) is quite small - only 250GB. The other drive is 1 TB and I have about 15 TB of externals available via Lightning connection. The problem is that the internal SSD is continually filling up, and since I have several mobile devices I am synching with iTunes, they are gobbling up tons of disk space on the startup volume. Is it possible to move MOBILE SYNC to a different drive? There is nothing in 'preferences' for mobile sync that can specify the volume where these files should be stored. They are taking up almost 85GB of disk space. My temptation right now is to clone the 1TB internal over to an external drive, then clone the SSD internal over to the 1TB internal, and make that 1TB internal drive the new startup volume, but it would require reformatting and reinstalling operating system software, since there isn't any on that drive.
I am sort of 'stuck' because when I setup a replacement iPhone on Monday from a backup of the previous phone (that had a defective antenna), about 100 recordings in the RECORDER APP were not restored to the new iPhone, and I need to dig through some iPhone backups to try to find one that might have them on it. I hate to lose some of those very valuable recordings from a one-week intensive graduate seminar.  Any suggestions for pruning the startup volume?
Disk Inventory X is showing only 7.2GB of open space and 225.8GB full on the SSD startup volume.  Here are the big space 'hogs:'
Users -  168.5 GB  (library 151.3GB; movies 15GB, which is odd, since all of the movies are stored externally.) In 'application support, MobileSync is taking up 82.5GB and Mail is taking up 47.9GB. (some of this mail goes way back, and needs to be archived, but I am not sure if that possibility exists in current OS)
Applications - 16.5 GB
Library  - 11.5GB
iMac  - intel (3 yrs old)
OSX 10.9.5
iPadAir
'the new iPad'
iPhone 5S
various other mac devices...

Answer 1

Well iTunes itself takes up virtually no space. I believe what you are suggesting is a move of your music files. Now these files can be moved to another drive and iTunes will act just like normal. The catch is that your music files pretty much have to be in one place. If you already have all your music stored in the My Music/iTunes/iTunes Music folder than you should be good. If you do not its a little trickier. In your preferences menu of iTunes under the advanced tab there are the options to "Keep iTunes music folder organized" and to "Copy files to iTunes music folder when adding to library". You will want both of these checked. Then under the advanced tab (The one not in the preferences menu) There is an option to consolidate library. This will copy all the music in your library not in the iTunes folder to the iTunes folder. Thus you will want to delete duplicated when the process is over. (If your drive is too slim on space for this opperation... then I don't know what to tell you.) With all your music in the iTunes folder just drag and drop said folder onto the new drive. Then under the advanced tab in preferences the first option is to change the location of your iTunes music library. Simply change it to where you have stored your library on the new drive and you will be set to go.