If your chime is too quiet or makes little sound, you should change the location of the chime. It simply does not get enough wind.
Sometimes they are hanging in a location where there is no wind at all or they are hanging not high enough. If you have placed your chime in a bush, try to hang it a little higher.
You can also try another branch, if your chime hangs in a tree.
Please also remember: the wind directions are sometimes changing.
You can also modify your chime.
Just use a longer cord for the wind catcher and it will chime more frequently.
If you compare the Zaphir chimes to the Koshi chimes, the Zaphir chimes need less wind to chime.
The cord of the wind catcher is longer than the cord of the Koshis and the wind catcher itself (the plate on the string) is bigger therefore the area where the wind touches is larger.