How to beautifully polish a musical composition cut out of a set and vice versa to combine two or one with itself?

Question

Audio

Sometimes there are beautiful musical compositions as part of continuous sets, where many tracks are sequentially combined into one audio file. Sometimes there is an interesting piece in one musical composition, and the rest is not very (in both cases, if you simply cut out the interesting piece in Audacity or SoundForge, you get a very ugly break). Sometimes you want to prepare a composition for staging in a cycle (for example, for a ringtone or an alarm clock), sometimes you want to make a small set. What to do in all these cases? It is clear that, in general, this is like a whole art / profession of a DJ or sound engineer, but in our progressive age, there must already be some tricks and utilities available to mere mortal geeks in occasional cases of this nature that occur in everyday life?
I still know two technologies - a smooth decrease in the volume of the ending track and "covering" the seam with something neutral, but firstly, both usually sound too clumsy, and secondly, even this is not known how to implement it in the context of editing an audio file (I met only in plug-in format for foobar2000 audio player). Or maybe there are some technologies based on pattern recognition, for example, that are able to analyze the rhythmic and frequency patterns and determine the optimal place for trimming, the optimal volume reduction curve and the optimal unobtrusive patch?

Answer 1

Listen to the rhythm (drums) and tone. Next, equalize the rhythm (bpm) of the two mixed pieces, then the key and equalize the volume. And cut at the end of the repeating piece.
Those. (lost in Russian) a pattern of several measures You need to select ...
And dock on the "strike" of the next pattern in a single note. (depends on the "strong" beat within the measure, i.e. on the style of music)

Answer 2

xmoonlight : The technique is very tool dependent.
Differences in work are cardinal...
As soon as you decide on the tool, you can report a brief algorithm of actions.