[Hal Rockwell]

Is there a way to straighten a dented diaphragm in a headphone driver?

 

[ThomasHK]

Putty or tape.

 

[silverfishla]

If that doesn’t work, try hot glue and the back of an eraser on a pencil. I fixed my B&W tweeter that way. It’s about the size of that diaphragm. A dab of hot glue on the eraser, set it on the dent, blow it dry (doesn’t have to be completely solid) then tug it. You may have todo it a few times to straighten it up.
Edit: sorry I thought the dent was in the middle. It still might work there, but just more difficult.

 

[GREQ]

Tiny piece of double-sided tape on the end of a plastic tool/spudger etc .. or just anything that isn't metal/magnetic.
Press it gently into the dent and pull out, gradually increasing the pressure and speed of pulling out if it doesn't work the first time.

 

[Twizzleshnizzle]

Appreciate it's an old post but I just had to carry out a repair and tried this technique. Worked a treat.

 

[Blotto80]

I usually put a bit of tape on the end of my finger and lightly dab at the dent and pull. Works well for me.

 

[lantian]

Since the look like this already, assume you have soldering tools. So Take a solder pump and put it on top and just use the pump function to suck up the dent, this way no s*** will be left on the driver. Do take care not to jab the pump into or through the diaphragm, also first hold the pump couple mm above the diaphragm, it might already be enough. Tested with Sennheiser HD 200 and a bit on broken hd 540 RG. Seems to work perfect, YMMW.