So I'm new at LMMS and I have a problem I don't understand. Chords sound 'wrong'. If I play a E7 on my guitar for example and then try to put an E7 into the piano roll with a piano sample, it doesn't sound in tune. I don't understand, shouldn't the chords sound exactly alike since it's the same chord?
Are you putting the notes in separately or selecting a chord from the list ? If you have all the right notes (E, G#, B, D) it should sound pretty similar except that pianos don't sound exactly like guitars. If you're picking from the list make sure you've selected 7 not one of the other 7th chords like Maj7 or m7. They'll certainly sound different.
If you're using samples (in AudioFileProcessor ?) then you can check the sample is "in tune" by checking individual notes i.e. does an E sound like the E on guitar (and are you sure your guitar is in tune ?)
Steve