How to eliminate a click which is heard in pd when sound-file or loop is playing? Is there any way to make playing the loop more filed and smooth, without this click noise between repetitions and at the end of the file?

I have this problem especially using [tabplay~] and looper patch.

clicks happen because of a sudden shift in your speaker cones. So, the best solution is normally to edit the waveform of the file you wish to loop, to make sure that at the end of the file (array) it doesn't end in a value like -0.859424 and jump to the beginning of the sound file with +0.9425342 e.t.c.

in fact it is good editing technique to make your loop points (edits) always fall when the waveform is at 0

Otherwise there are other ways to cheat, I.e fades or cross fades, but programming an effective fade is more hassle than it's worth.

the simplest way is just to edit your sample in a sound editor so that the start and end points both ramp to zero. use about a 5-10ms fade in/out on each end.

the nest simplest way is to do exactly the same process in realtime in pd. when you load your sample into a table with [soundfiler], the output of [soundfiler] gives you the sample length in bytes. just divide this by your samplerate (usually 44100), or you can use the [samplerate~] object to make a generic one. then you have your sample length in milliseconds. subtract 5 milliseconds from that value to account for the ramp down time, and feed it into the [0, 1 5, 0 5 $1( message in the construct below. the millisecond value must be banged at the same time as the [tabplay~]

[tabplay~]
|
| [0, 1 5, 0 5 $1(
| |
| [vline~]
| |
[*~ ]

otherwise, there are also some crossfade samplers and whatnot in the pd audio documentation.