After having another look at the old speakers, it is obvious that they have been disintegrated due to age. Although, I found some more smaller speakers that seem to be in good condition:
Specifications: "TEAC 5111 - Two-way, 2" tweeter, 4" woofer, 60-20,000Hz frequency response, 50 watt maximum power at 8 ohms."
Is this any good?
I also found my older CD Player, a "TEAC PD-230 Compact Disc Player", and my Amplifier, a "TEAC TA-680 DC Integrated Stereo Amplifier", with the speakers. I'm expecting these to be quite ancient...