well id say it really depends what you are sampling and what using to make beatz i use hardware and i tend to stick to more acousic basses if im adding a bass to a sample thats sumthin of a isley brothers pendegrass era because your trying to match a bass to a live band sound if im sampling a 80s cameo or zapp and roger track then i might put an analouge or synth bass because it matchs better ....... its really just practice and buliding up your library of sounds im not sure your gonna find a "how to guide" on matching basses to samples its all in yuor ear and what sounds good........ so samples are just too low frequency recordings and no bass sounds good it just distorts it sum samples are really trebley and just sound bad if your tryn to add an 808 type high hat or sumthin ... its all time ..... there is no easy way to gettin good at makin beats besides practice....... but you can make a bass line on any keys not just the black keys .....lol you just gotta match the notes or chords that the song you are sampling is