Hey. There really is no true answer tot his after a certain point because each song will react differently to different bitrate settings. Generally, if something is recorded at 128kbit and has a fair amount of hihats going on with other sounds in the mix, they tend to sound a bit strange or produce audio artifacts. One way that sometimes presents this is by making sure you aren't encoding in a joint stereo mode but, rather, compress each channel without one being compared to the other. There is likely a setting for that in your codec/software. Sometimes, you'll get the same problems with audio artifacts at 160kbit or 192kbit. If it's your music in it's purest digital state and you know how it sounds, best bet is trial and error. Start at the lowest bitrate you're willing to go (and starting at 160kbit is good because, generally, 128 will cause some noticable artifacts) and just see if the final output sounds close enough to your original track that it doesn't bother you. If it does, set the kbit a
notch higher and keep going.