I second what McGrath says. I'll repeat what he said in American English.
Get an 8 foot long 2"x4"
Paint or stain it or leave it unfinished.
Use 2 large hex headed lag bolts to attach it solidly to two studs as close to the ends as possible. (The hex heads will make it easy to remove them with a socket wrench at a later date.)
Use the hooks of your choice.
If you've anchored it into the studs. It won't come down unless the wall comes down. (a distinct possibility during an earthquake, but in that case I won't make any difference where the instruments are).
I've done this for years on both inside and outside walls.
No problems.