I've been messing around with music mashups for over 3 years its a lot of fun
heres the acapella I've been using it's not too bad when you have both the original song and a full instrumental available but theres always some noise going on if the two arent mixed 100% the same
https://www.dropbox.com/s/vgk4pj28vmgydn5/stepping%20wind%20acapella.mp3one I made just now with less noise, just every time you do this the audio quality keeps deteriorating maybe it has gone a bit too far, you can go even further than this if you want
https://www.dropbox.com/s/p8htmyeilxvjzyz/stepping%20wind%20acapella%202.mp3feel free to use either of these for anything you like I don't own anything enjoy it
instrumentals I usually find on youtube, you can search for almost any song you like and there will be an instrumental track either original or fan made.
I'm a big fan of mashups being a bit rough sounding I think it is funny, for example when klonoa finishes his verse in "eye in the sky klonoa" this crazy raygun sound starts up and klonoa starts yelling wahoo just to fill the dead space before the hook
my thinking is that all the noise is right there in the acapella file so might as well get some use out of it
I keep trying to incorporate that sick synth break into the mix I think it's always a cool and funny part of the song when I put it in
as for mashing chords together I love doing this and it's present in my own music as well for example this song
https://www.dropbox.com/s/9emnse5t6w48349/e1m8.mp3 I think it makes the track a lot more energetic