# shift title text up with line

I have been inspired by this link; Shift title and author text up? but when I use the tips on my own group (not using title). I still get that the text starts farther down on the page. I think this is a default with report-documentclass....does anybody have suggestion on how to push the text farther up on the page? or alter the report class somehow to achieve the same?
here is my current document state;

\documentclass[12pt,a4paper,onecolumn]{report}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}

\begin{document}
\begingroup
\centering
\LARGE "title"\\[0.1em]
\large "subtitle"\par
\endgroup


\vspace*{-2cm}