I know what they are and where they come from since I recently opened a pair of Tandberg Hifi System 11!
The number HTB113/4 indicates with 100% certainty that it's a Tandberg speaker.
I was earlier sure that it's a Goodmans unit since it has that black,soft suspension seen on other Goodmans speakers,the right color and that old "shelf" used long ago as a mounting for transformers.
Your Goodmans label now confirms this.Thank you!
Picture of my Tandberg 11: