Its actually really easy and the repair works a charm (it will also work on larger speakers). The trick is good old elders glue and single ply toilet paper. A paper towel will work as well, just be sure to separate the ply... it needs to be thin. In this picture, I've mixed some elmer's glue with warm water.

In my case, there were a bunch of small tears. I cut out little strips of tp and placed them over each tear.

Use the paintbrush to help form the tp to the shape of the speaker cone. It doesn't need to be perfect (mine isn't) but it should be a flat and formed as possible when done.

If you can turn the speaker around, you can (and should) apply to to the tears on this side as well. This speaker has a protective back, and only a couple of tears are accessible. There. That's better.

Go over the edges of the toilet paper on each repair one more time. If an edge doesn't adhere, it may flap and make noise when the speaker is activated. If you're very careful, you can make the tp perfectly flat on the cone (no wrinkles). Mine has wrinkles. Wet each wrinkle again to make sure it lies as flat as possible. I've never had trouble with a wrinkle... it's mostly the edges that create issues.... still, it looks nicer if laid perfect. This speaker will be hidden when placed inside the radio case. *** Now we just let her dry.

You can see that as the repair dries, the white of the paper shows again.

If you need to color it, use a water based marker or other lightweight dye. Don't use paint. It's too heavy and will alter the soundquality in a negative way. I'm using a cheap water color here.

All painted. I'll take final Pic when it's dry.