((I realize this is a very volatile thread, so I will not reply with my usual snark and humor and so on.))
But quality control issues, and mistakes are part of all manufacturing, Pro level, retail level and diy.
I have seen diy products that are better made than many retail offerings, and others that were lacking as you say.
But using a blanket statement, will often infuriate a lot of people, as there are many members in the forum that are not only into diy speakers, but have moved from Diy for personal use, into small businesses.