...um a Q of 0.8 is not overdamped at all.
0.707 is called "critically damped" and the range between that and 0.5 is generally considered optimal damping for a filter. But speakers are a little different.
In a dipole speaker 0.8 is good, since there is no cabinet with an air mass to interact. Even 1.0 is ok fine. Gets you a bit more bass in the real world.
But, if there is overlap between the -3dB point acoustically of the dynapleat in the baffle and the subwoofer, then some adjustment is in order with either the sub's xover point/slope and/or the dynapleat's roll-in - which would imply a high pass.
However, things would likely sound best phase wise without an xover, but again that depends on the phase relationships between the drivers around the xover point anyhow.
Using a high pass will REDUCE the excursion of the dynapleat due to LF energy that does not produce usable output, and so increase the power handling, thus it is not a bad idea in practice,especially if you want to play them loudish.
_-_-bear
0.707 is called "critically damped" and the range between that and 0.5 is generally considered optimal damping for a filter. But speakers are a little different.
In a dipole speaker 0.8 is good, since there is no cabinet with an air mass to interact. Even 1.0 is ok fine. Gets you a bit more bass in the real world.
But, if there is overlap between the -3dB point acoustically of the dynapleat in the baffle and the subwoofer, then some adjustment is in order with either the sub's xover point/slope and/or the dynapleat's roll-in - which would imply a high pass.
However, things would likely sound best phase wise without an xover, but again that depends on the phase relationships between the drivers around the xover point anyhow.
Using a high pass will REDUCE the excursion of the dynapleat due to LF energy that does not produce usable output, and so increase the power handling, thus it is not a bad idea in practice,especially if you want to play them loudish.
_-_-bear
greetings bear
Actually, I think critical damping is defined as a Q of unity. Conventional wisdom says that the optimum damping of a cone driver in an enclosure should be .707 due to the overhang that occurs with most relatively massive woofers.
When I built my system, I knew I was going to use a biamped subwoofer and could adjust that crossover point to fine-tune the low end. As you say, a high-pass filter could affect phase response in the mid and upper bass and I preferred to avoid any possible loss of coherency in the range of the Dynapleats. In that overlap region, however, there are probably many things going on. I admit to some luck in getting a result that seems "just right".
I haven't detected any lack of control in the Dyanpleats, even at higher listening levels. The perforated sheet introduces what is called a mixed-mass resistive element not unlike a resistive port in a reflex enclosure. It provides some frequency dependent damping, greater at the low frequencies.
Actually, I think critical damping is defined as a Q of unity. Conventional wisdom says that the optimum damping of a cone driver in an enclosure should be .707 due to the overhang that occurs with most relatively massive woofers.
When I built my system, I knew I was going to use a biamped subwoofer and could adjust that crossover point to fine-tune the low end. As you say, a high-pass filter could affect phase response in the mid and upper bass and I preferred to avoid any possible loss of coherency in the range of the Dynapleats. In that overlap region, however, there are probably many things going on. I admit to some luck in getting a result that seems "just right".
I haven't detected any lack of control in the Dyanpleats, even at higher listening levels. The perforated sheet introduces what is called a mixed-mass resistive element not unlike a resistive port in a reflex enclosure. It provides some frequency dependent damping, greater at the low frequencies.
Crossover addendum
In case you're getting close to buying the coils (inductors) or winding them yourself, I wanted to mention that I changed the values on mine and prefer the newer version. I changed the .6mH to 1.5mH and changed the .3mH to .6mH. The overall sound is now a bit less hard in the upper midrange when the music has a lot of energy in the lower treble range.
I wanted to post this before they make changes in the website. My experience is that website changes usually give me a real headache since I use a non-standard browser.
regards, and I hope you're making progress.
In case you're getting close to buying the coils (inductors) or winding them yourself, I wanted to mention that I changed the values on mine and prefer the newer version. I changed the .6mH to 1.5mH and changed the .3mH to .6mH. The overall sound is now a bit less hard in the upper midrange when the music has a lot of energy in the lower treble range.
I wanted to post this before they make changes in the website. My experience is that website changes usually give me a real headache since I use a non-standard browser.
regards, and I hope you're making progress.
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