Controlling space after heading when doublespaced

Question

I'm writing a document with both doublespaced and singlespaced sections. I'm using the setspace package to do the doublespacing and the koma-script report class for the document. In the double spaced environment the space after the heading is larger. This is obvious in my MWE:

\documentclass[12pt, letterpaper]{scrreprt}
\usepackage{setspace}
\usepackage{lipsum}

\begin{document}
\chapter{chapter1}
\doublespacing
\lipsum[1-2]

\singlespacing
\chapter{chapter2}
\lipsum[1-2]
\end{document} 

I really want the space to be the same regardless of the line spacing, the first line should start a fixed distance after the heading. I can tweak it manually with a vspace but I figure there is a proper way to do this and if I tweak it manually then sections I don't have control over like the bibliography. How can I fix this. I tried adjusting the parskip before the section but this also moves the heading down.

Answer 1

This might be automated, but it seems that

\cleardoublepage
\singlespacing
\chapter{Double spaced chapter}

\doublespacing\nointerlineskip

for a double spaced chapter and

\cleardoublepage
\singlespacing
\chapter{Single spaced chapter}

for a single spaced chapter may be what you need.

Some problems might remain for the cases where \chapter is automatically generated, such as the table of contents.