Reddit mentions: The best eyebolts

I'm reading this as there being a code/ elfin-safety requirement that there be a "safety" on the speakers in spite of them being quite lightweight and quite securely mounted.
If this is going to be inspected by someone familiar with entertainment facilities, then random chain screwed in with a washer may not successfully meet the requirements. Chain that is formed by twisting or bending without welding of the links is right out, on fear that in a fire situation the softened metal will unbend.
The right way is detailed here:
http://www.jblpro.com/pub/technote/tn_v1n14.pdf

Now, on to practical details: if that bracket that you show falls off the wall, then the safety on your loudspeaker needs to secure a dynamic load of not just the 2kg speaker but also the 3kg bracket. The rule of thumb for rigging of dynamic loads is multiply the load by 5, and that gives one the required rating of your hardware, assuming that all hardware is used correctly.
For attachment to the speaker itself, the right way is to use a forged shoulder eye bolt, bolted right through a surface of the box, with a big-enough backing plate that it won't pull through with a sharp 25kg tug (it's not the fall that is the problem, it is the sudden stop at the end...) No-one trusts a screw (self tapping or otherwise) in this situation.
Then I would suggest a standard lighting safety cable of appropriate length to lasso the beam and clip to your speaker eye.
On some speakers it is pretty obvious how to remove the woofer so that you can peer in and see where it is safe to drill. You also want to be sure that a sudden tug on the top/back/side face of the box (as appropriate) isn't going to just disconnect that face from the front face which is carrying all the weight of the heavy magnets in the drivers.

Hey OP, First of all, nice rack!

Secondly, a lot of people are commenting about your choice of hook for which you've hung the chains from.

Most of the commenters are correct in saying that the 40kg load is rated for a vertical tension, rather than a horizontal shear/bending (like you are using them here), but no one has offered up much advice, so I thought I would give you my 2 cents.

If you are at all worried about the rack falling, you could switch to something like these and use something like these to hang the chain.

This is still decorative and they come in many sizes, shapes, and styles. Many are shorter on one side, so you will have some play with how far out from the wall you want your rack to hang.

• Car Key
  
• iPhone 6s
  
• Leatherman Wave
  
• ThruNite Ti5 NW
  
• Dopp Regatta 88 Series Front Getaway Pocket
  
• Fisher Space Pen
  
• Field Notes - Pitch Black
  
• Ruger SR22 (While I save up for an M&P Shield 9mm)
  
• Brass Swivel Snap
  
• Leather key fob
  
• House & Office Keys
  
• LaCie iamakey 8GB USB drive
  
• Swiss+Tech Utili-Key
  
• Kershaw Leek BlackWash

they do make eye bolts that are much shorter than what you can find at home depot.

something like this

again, check with a local ace hardware. their stores near me carry every uncommon piece of hardware you could imagine. if you don't have one nearby, i'd cut down one of the eye bolts you can find. i like the idea of being able to loosen the bolt and sliding it out of the channel instead of drilling through the roof rack.

Get something like this and screw it into a stud:

https://www.amazon.com/Forney-61369-Shoulder-Galvanized-2-Inch/dp/B003XEW5E4

They also make them with the same threads as a toggle bolt, so you could construct a toggle eyebolt.

If you do use a fish eye bolt, make sure it is welded closed. Welded hooks will hold a lot more weight and are usually made of higher quality steel.

-the one in the link is stainless, which is unnecessary, I just wanted the visual of a welded bolt

That Eye Bolt is designed to slide through a hole and have the nut serve as the main method of securing it in place. If you want to screw it into wood, and have the wood do the work, then you need a coarse thread wood screw eye-bolt. If you want to use the eye bolt you noted, toss a fender washer on it.

These could also work.

I use a 100 foot "clothesline". I bought a leash clip at my local hardware store.

This is the kind of cord I used. Wear leather gloves--it can savage your hands.

I used something like this clip.