Looks like it forms a filter Stu but I always forget which is which in a schematic high pass or low pass
Any capacitor will work but value will obviously change what frequency passes through it to ground, higher value = more bass as you know
If you have a 1uf film or ceramic you can use that or you can wire caps in series e.g. 2 x 2u2 would give you 1u1 but it doesn’t look too good so I never do that
I generally use the closest value and remember caps have a + or – 20% tolerance so a 2u2 for example could range from 1.7 to 2.6