creating upload folder on the fly in laravel

i know know how to create upload folder on the fly. ihave songcontroller. and this is mode store method.

public function store(Request $request)
    {
        //
        $this->validate($request, [
            'title' => 'required',
            'lyrics' => 'required',
            'youtube_id' => 'required',
            'album_id' =>   'required|integer',
            'category_id' => 'required|integer'

        ]);
        $song = new Song;
        $song->title = $request->title;
        $song->lyrics = $request->lyrics;
        $song->youtube_id = $request->youtube_id;
        $song->album_id = $request->album_id;
        $song->category_id = $request->category_id;

        if($request->hasFile('mp3')){
            $mp3 = $request->file('mp3');
            $trackname = $mp3->getClientOriginalName();
            $path = public_path('/uploads/songs');
            $mp3->move($path, $trackname);
            $song->mp3 = $trackname;
        }
        $song->save();
        $song->artists()->sync($request->artists, false);
        return redirect()->route('song.index')->with('success', 'New song successfully upploaded');
    }

i wanna create a folder for every artist that belongs to song that is being uploaded.

via Chebli Mohamed