Hi Pete, I tried you mod with great success !
This should be part of every system running Advents.
I built the 4.7K, 4dB version. However my NAD 214 power amp's input impedance is listed as 60K, so I'm a bit off with the values.
I was wondering if it would be possible to integrate this circuit into the speakers crossovers themselves. That way, there would not be any need for different versions.
That might be more complicated to calculate however, and I'm not qualified to do the design. It will be more expensive to build, of course.
What do you think ?
Another option would be to build an active filter, with an op-amp buffer so it can be plugged into anything without concern to impedance matching.
By the way, I've drawn a schematic of your circuit, taken from your ascii drawing in post #41. Note the reversed IN-OUT captions ! They are in conformity to the ascii drawing.
Maybe it would be appropriate to post a corrected version, so beginners without electronics knowledge could easily manage the build.
Thanks for everything,
Ah! So that is why several people put the BSC in backwards!
My schematic in post 41 is correct when all the spaces in the
diagram are left in, the board removed them however, and
made it look like the shunt RC network to ground goes at the
input. I made note of this when I first posted it when this thread
was on the old forum board, and I think that the spaces were
lost again in moving to the new board.
Yes, your diagram is backwards, and please correct it.
The 4.7K version is designed for a 47K ohm load, your is 60K
so the simple thing is to just put a resistor across the output
of the BSC so that the combined parallel resistance is about
Yes, those are all good possiblities, passive at the speaker,
with an OP amp - however I wanted to keep it simple.
Passive at the speaker has some issue with the complex
impedance of the speaker load - it can be done. Also, the
LA, and New LA have very different impedances at high
Have you ever used a SPICE circuit simulator? Or even better
a speaker system simulator?