[tiborsaas]

I was also put off by the static, repetitive sounds. My suggestion would be to record 5-10 sounds and pick randomly, slightly tuned them up/down with some filtering.

[CodeWriter23]

Different hammers on an old typewriter made different sounds likely due to differences in mass and the angle of approach.

[thfuran]

But since audio provides a potential vector for side channel attacks, randomization is better.

[SoftTalker]

And also because human typists don't always strike each key with the same force.

[varispeed]

That should really be recorded in stereo and at least 20 samples for each key, possibly at different strength and then some sort of algo that would pick samples depending on how vigorously someone types.

Then that still wouldn't capture the intermodulation etc.

It's a lot of work to actually make it sound remotely realistic.

[tiborsaas]

+1 on all these, and don't forget that the keys make a sound too while they travel back to their resting position.

[numpad0]

Maybe the sound should be played in proportionate intervals to typing speed, rather than upon "hits", with the last one somehow cleverly ending with key-up and/or first key-down inevitably absent.