Polyphony Problem Hopefully Solved

[Philip]

Formerly, I did en-close the entire expression in double brackets

<<

% top voice

\\

% bottom voice

>>

but forgot to en-close the notes in braces, but I was ignorant of it. So 
I tried using

\new Voice

but this, as I have said, did not work. But I read in the link I was 
given and it said that with double-angle brackets the notes for voices 
had to be en-closed by braces

<<
{
  % top voice
}
\\
{
  % bottom voice
}
>>

which should hopefully solve my problem. But then what is

\new Voice

used for?