Have you tried lowering the velocity?

Yes - but lowering the velocity lowers the volume and in fact the volume is too low in general. So if I put the velocity up to get more volume, the attack just gets even harder. What I would like would be the gentle "p" attack but with much more volume (as if the instrument was played softly but closely miked) but I can't get this effect at all. What I have is, in fact, quite the opposite: low volume but hard attack - the worst possible combination! So any clues will be greatly welcomed.

I have the computer audio volume on max, the mixer volumes on 118, the VST volumes on 135 and 170, so every possible avenue is explored to get more volume so as to be able to use lower key velocities .

This is not a free option, but Garritan makes a Harps package with various makes of Harp and gives greater control over the instruments.

I no longer use Garritan, here's other options.

Use NotePerformer when using Finale for playback.

https://www.noteperformer.com/ 

When using a DAW, I use the harp from Spitfire Audio.

https://www.youtube.com/watch?v=FNNKGBHDEhA&t=2s 

Thanks Jeffrey and J Adrian. As I don't use the harp sound much it's not worth buying the harp package. The hard attack/low volume problem is a recurring problem with many instruments (guitar and even the piano) so it would be good to find a global solution. Perhaps I would need a DAW. I tried the NotePerformer trial version but could only get the piano sound for some reason. Sent them a message to see if this can be resolved ......

With NotePerformer, you have to follow the Finale instructions to the letter and they're not intuitive. Once you get it to load properly, it's pretty easy to do what you need.

I've not tried the NP harps as I have a number of other harp libraries incl. Garritan (which is pretty good) and my go-to in SampleTank but I might give them a try next time.

Yes, exactly, Mike. I missed one instruction, but they replied immediately and sorted it out. Works well but still not the great sound I'm looking for. Thanks for the tip. I'll have a look at SampleTank.

Let's hope one day there will be a Finale mixer with VSTi and MIDI per stave.