Thanks above for all your support to me. Usualy life in this country is not to much easy if you need to buy some of special electronic tools. e.g. Any price for osciloscope is more then doubled but payroll for our work is not to much high. We can to buy that equipment from all EU countries but when we buy this equipment we have high taxes. As I say before, I have all these measurement equipment on my workplace but I need to move all my audio equipment to the workplace then work on it and after that I need to move all that things back to my home to hear is that changes good or not. So, my only choice is to inspect precision on my sound card and software what I use on workplace and see is it ok for that or not and move this soundcard back to my home and use it with best what I can. In the near future I`m thinking to buy some simple 2ch osciloscope... For any analyze on audio files I use ARTA software. I`m looking on some HANTEK or Velleman WFS210 or any similar DSO... What you can to reccomend to me for that purpose and with low price? @cizeta Thanks for software, I will try it.