It's been exactly a year since I've owned the speakers.
A fellow audiogoner bravely took the step of following my crossover mods and is quite pleased with the results.
Recent communications with him sparked my interest in further pursuing the improvement of the still somewhat lethargic, constricted, and occasionally "one-note" bass as most evident in Holly Cole "I can see clearly now" and Eagles Live "Hotel California."
I removed the woofer crossover board and carefully took measurements of the components. It's a 4th order crossover with L1=1.2mH C1=390uF L2=530uH C2=220uF.
What disappoints me is the DC impedance of the inductors.
1.1 Ohm and 1.0 Ohm respectively.
The 2 woofers are wired in parallel. 6 Ohms nominal per driver that makes it 3 ohms. With the inductors of such high impedance, no wonder the bass is lethargic. Kind of like having to drop 1/3 of the power before getting to the drivers! Better inductors of similar values should be 0.12 Ohms (Check Michael Percy Audio or Partsconnexion)
A friend suggested that I do some tspice simulation of the circuit. Ouch, this crossover is extremely notchy and phasey (the phase shift as the frequency increases is not smooth at all.) The woofers are 4th order, the midrange is second order for sure. A rather strange combination.
A friend suggested I use tspice and come up with values for just a Butterworth 4th order and run simulation to verify the drop is smooth. I compared the 2 plots and decided to be adventurous. Ordered the parts from Partsconnexion and THEN I realize how much bigger and heavier those inductors are. Even the strap on 68uF Mundorf bipolar lytic is 3 x the size of the incumbent 390uF (I need 460uF for C1).
This is a much much more involved mod than the cap replacement of the mid and tweeter obviously.
Took me many hours figuring out how to mount them creatively and somewhat non-invasively without having to build it externally. But even with only 1 speaker done I was able to tell the difference putting my ears close to the woofer. There is a world of difference in clarity. Another hour gets the 2nd channel done... drum roll...
There is a lot more dynamic contrast in the bass notes. The decay characteristics of one drum beat vs another is clearly evident. It doesn't go any lower than before, but has the "fast bass" (a term used by Avalon's Niel Patel) that never existed with these speakers. Listening to no less than 10 of my favorite bass-challenging recordings I don't hear any note that stands out or causes a nasal sound.
I'm not quite done yet. Ultimately I might just build an external crossover box for it so I can replace ALL bipolar lytics in the crossover and see if I can take it up another notch.
A fellow audiogoner bravely took the step of following my crossover mods and is quite pleased with the results.
Recent communications with him sparked my interest in further pursuing the improvement of the still somewhat lethargic, constricted, and occasionally "one-note" bass as most evident in Holly Cole "I can see clearly now" and Eagles Live "Hotel California."
I removed the woofer crossover board and carefully took measurements of the components. It's a 4th order crossover with L1=1.2mH C1=390uF L2=530uH C2=220uF.
What disappoints me is the DC impedance of the inductors.
1.1 Ohm and 1.0 Ohm respectively.
The 2 woofers are wired in parallel. 6 Ohms nominal per driver that makes it 3 ohms. With the inductors of such high impedance, no wonder the bass is lethargic. Kind of like having to drop 1/3 of the power before getting to the drivers! Better inductors of similar values should be 0.12 Ohms (Check Michael Percy Audio or Partsconnexion)
A friend suggested that I do some tspice simulation of the circuit. Ouch, this crossover is extremely notchy and phasey (the phase shift as the frequency increases is not smooth at all.) The woofers are 4th order, the midrange is second order for sure. A rather strange combination.
A friend suggested I use tspice and come up with values for just a Butterworth 4th order and run simulation to verify the drop is smooth. I compared the 2 plots and decided to be adventurous. Ordered the parts from Partsconnexion and THEN I realize how much bigger and heavier those inductors are. Even the strap on 68uF Mundorf bipolar lytic is 3 x the size of the incumbent 390uF (I need 460uF for C1).
This is a much much more involved mod than the cap replacement of the mid and tweeter obviously.
Took me many hours figuring out how to mount them creatively and somewhat non-invasively without having to build it externally. But even with only 1 speaker done I was able to tell the difference putting my ears close to the woofer. There is a world of difference in clarity. Another hour gets the 2nd channel done... drum roll...
There is a lot more dynamic contrast in the bass notes. The decay characteristics of one drum beat vs another is clearly evident. It doesn't go any lower than before, but has the "fast bass" (a term used by Avalon's Niel Patel) that never existed with these speakers. Listening to no less than 10 of my favorite bass-challenging recordings I don't hear any note that stands out or causes a nasal sound.
I'm not quite done yet. Ultimately I might just build an external crossover box for it so I can replace ALL bipolar lytics in the crossover and see if I can take it up another notch.