31-01-2019, 07:27 PM
The term "active loudspeaker" might be something as simple as a speaker with an amp in the same box. Most computer speakers are like this and it seems entirely sensible. both for this sort of speaker and also for high quality designs. The BBC LS5/8 is a well known example. This used the 2 channels of a Quad 405 amp to drive the woofer and tweeter of a high quality monitor speaker. There are obvious advantages in doing the crossover at low level. Also sending the signal to the speaker at line level (balanced in a professional design) avoids any issues with speaker cables.
I'm am little surprised that motional feedback or something similar hasn't become more common. Electronics are cheap and it could be a good way of getting high quality audio out of a small and cheap speaker.
Many years ago I dimly remember reading about feeding square (square-ish?) waves into different loudspeakers and looking at the result using a measurement grade microphone. Apparently the results looked horrible except on the Quad ESLs. I think this was before the ESL63 was around.
I'm am little surprised that motional feedback or something similar hasn't become more common. Electronics are cheap and it could be a good way of getting high quality audio out of a small and cheap speaker.
Many years ago I dimly remember reading about feeding square (square-ish?) waves into different loudspeakers and looking at the result using a measurement grade microphone. Apparently the results looked horrible except on the Quad ESLs. I think this was before the ESL63 was around.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
