Is ther any way I can change this pitch of the dump valve? They are very high pitch I would like to have it abit more deeper sound if can change it at all.

Cheers

Should be able to alter the spring for the pressure to release and the filter inserts  to change it. 

Dnt think this one is a spring is it? It seems to already have one filter in looks but like the shape of Mercedes badge. If I took that out should be a more deeper sound would u think.

I would have thought so its a filter so will restrict air out so removing it should make it louder I know you can get other filters for them youtube has video of all 3. And it will work on some sort of spring mechanism to be able to open and close but im not sure how or if it can be set with them ive never owned a hks dump value.