Added to the test videos, you will find some of the guitars have test bench videos and the reason for this is to share with you some of the more pedagogical strong points and weak points of an instrument. The exercise is not easy because it has to be subject to an objective point of view.

No youtube playlist videos to be found - maybe API key not set ? This is the feed - https://www.googleapis.com/youtube/v3/playlistItems?part=snippet&playlistId=PVPsd1kYR39A-bo0cOekRKBrOekuNGMu&key=AIzaSyDD5qFtvhPJxKvjUomTE_qCHWQZfszyoUQ&maxResults=20
The playlist identified with the request's playlistId parameter cannot be found.
Gallery banc essai does not seem to have any videos.