Is this good idea for diffuser?

[Damian.DJ]

This is a 3mm hardboard, flexible enough to bend to this form. Would this work well at the back of the room, covering doors that are in the middle of the room? Should I place inside some mineral wool. Thank you for all your opinions.

 

[raindance]

This would not be a diffuser except perhaps for high frequencies, but it would have unpredictable behavior. If you fill it with mineral wool it will be a limited bandwidth absorber for low-ish frequencies. An example of a diffuser below:

 

[Damian.DJ]

Great looking one. I got my idea after this example. Price of my one is 30x lower but I am not sure if I can get same results.

 

[raindance]

What is the acoustic problem you are trying to solve?

 

[Speedskater]

The ones in the first poet are:
polycylindrical diffusers
Probably the most common type of diffuser over the last 75 years.

 

[DVDdoug]

If you are going to do something that "big & drastic" I'd recommend getting a measurement mic and measuring before & after.

I'm NOT an acoustic expert but my "intuition" tells me that you don't need such a big radius... I don't think you can effectively diffuse low frequencies (long wavelengths) in a small room. It should be OK to make it big (height & width) to minimize the flat surface area in the room. (Again mostly intuition.)

 

[kiwifi]

This is a 3mm hardboard, flexible enough to bend to this form. Would this work well at the back of the room, covering doors that are in the middle of the room? Should I place inside some mineral wool. Thank you for all your opinions.

No reason why they shouldn't work. Remember that you need to be at least a couple of meters away from the diffuser to get to the benefit.