Fingerboard height and bridge height
I'm a beginner and I have an issue with my violin.
I realized that the fungerboard is low and due to bridge height it requires high pressure on the strings to get the notes.
I made a research and found that the height of the string at the end of th fingerboard is what matters, so I adjusted the bridge height to get the G string height to 5.5 mm and the E string hight to 3.3 and that make it easy to get the notes.
The problem is the G string is vibrating more than before and the sound on all strings is more scratchy.
So how can I fix my violin?
Take it to a luthier and get a new bridge cut. Violin adjustments of the kind you are doing are not what beginners should be even contemplating. Did you replace the bridge in exactly the same place? Is the curve correct? String spacing right? Did you lubricate the grooves? Do yourself a favour and leave it to the experts.
There are too many things to go over in a post that's for sure. Check everything from how you wound the strings on the pegs to how the strings come out of the tailpiece. Is the bridge set at a 45. Is the sound scratchy or are you hearing ring tones. Did you double check the width of the top edge of the bridge with an adequate taper after you lowered the height. Often times the lower end violins come with a small tube over the E string to protect the bridge from the string cutting into it- if you have one is the tube in place. I agree with Carlo, find a luthier.
How did you adjust the bridge height?
The height of the strings in the lowest positions is also controlled by the grooves in the nut at the edge of the pegbox. String height above the fingerboard in that region should be about the width of a business card - roughly the thickness of 32 - 50 weight paper/card stock (I think - but it might be a bit thicker - don't trust me on these numbers).
nut height above fingerboard = 1.5mm at edge by the G and 1mm at the edge by the E - string height 1/2mm from fingerboard, "Violin Repair Guide", by Michael Atria.
Weisshaar says strings above fingerboard at nut by the thickness of a business card paper, I believe.
that's about 1/2mm
Everyone is addressing the string height above the fingerboard, but none are saying anything about the fingerboard projection. Our op said that his fingerboard is low, which likely means the neck has sagged. If so, shortening the bridge is not the way to a fully functional violin.
Given that a neck reset would probably cost significantly more than the cost of the OPs violin, I don't think that really is an issue that anything can be done about.
Given the little information and no image of the violin or history of, make it kind of hard to troubleshoot through text. Something that should be done with a luthier and in person anyway. Heck, being a beginner it could be he just isn't bowing at the right speed for the weight he is applying to the bow. He didn't say how "beginner" he is either. As I said before, there is way too much involved to analyse in a post.