generally speaking, it is genuine CD conversion, that is, using purchased high-quality CDs, using EAC(Exact Audio Copy) to grab tracks to get wav, and then lossless conversion to APE, FLAC or other lossless formats.

however, because some people don't understand it, they convert the downloaded MP3 into APE, or use the D version of the CD to make it lossless, which will not only make the file size large, but also make the sound quality not high. Therefore, when lossless music is generally released, it will be accompanied by spectrum analysis.

of course, even the genuine CDs have great differences in quality. For example, some CDs I transferred, the high-pitched part of the original foreign CDs is much better than the genuine ones in mainland China, or the quality of the one I bought is not good.

I hope it can help you.