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Hi Jim,Do existing orders with the original upgrade path get the new version of it, or will they still get the old version?
If one gets no other upgrades besides the cap upgrade, exactly what audible improvements can be expected vs. stock?
What type of crossover is used: first order, second order, etc.?
In both cases, the driver integration is seamless.
rblnr -Quote from: rblnrWhat type of crossover is used: first order, second order, etc.?The passive crossovers are 4th order with an additional trap circuit on the midrange. This is critical with the W18 in order to avoid cone resonances. The W18 is an incredible driver when cone resonances are taken into consideration.
In the active version, 96db slopes are used. In this case, the additional trap circuit is not needed.In both cases, the driver integration is seamless.- Jim
"You mean a notch filter? So you need a 4th-order crossover and a notch filter to tame the W18? Ouch"Hi whether you call it a trap or a notch, it's just an inductor, cap, and resistor in line. The crossover is 4th order acoustic, not 4th order electrical, so you don't end up with as many components as you might think. A trap plus 4th order electrical would give you at least 7 components just for the low pass. The 4th order acoustic with the lcr filter only uses 4 components.
The crossover is 4th order acoustic, not 4th order electrical
QuoteThe crossover is 4th order acoustic, not 4th order electrical"I think I understand the difference between acoustic and electrical in this case, but could you elaborate?"Hi. I can try. Let's just worry about the woofer circuit in a 2-way. And let's suppose the woofer's response is perfectly flat from 40 Hz to 20,0000 Hz. And it's impedance curve is a perfectly flat 8 ohms above 100 Hz. Of course, nothing like that exists on this planet, but just assume it for the moment. Then, in order to roll THAT woofer off at the top at a 4th order slope--24 dB per octave--you would need to use four components. A series inductor, a capacitor to ground, another series inductor, and then another cap to ground. That's a 4th order "electrical" circuit. It assumes a woofer that essentially behaves like a simple and prefect resistor. Real-world woofers aren't flat. Not only do they have peaks and dips at the top end (say between 3 kHz and 5 khz). but they have a natural roll-off at the top end. And their impedance increases rapidly as you go above 1 or 2 kHz. If your goal is to roll THAT woofer off at 24 dB per octave--so that its "acoustic" output falls by 24 dB per octave--all bets are off concerning what crossover components will be needed to accomplish that. With the W18, all that's needed is a series indcutor followed by an "lcr" circuit to ground. That's an inductor, capacitor, and resistor in series with each other, but connected to ground after the series inductor. The "lcr" circuit is a tuned "trap" that suppresses the W18's big breakup peak just below 5 kHz. That suppression, combined with the natural roll-off of the W18, is enough to produce a 24 dB "acoustic" slope when it's preceded by a series inductor.
DMurphyOut of curiosity, are additional components needed to knock down the upper Hz resonance in the Mag driver after you have hit your target 24db/oct with 4th order XO?Thanks for your informative postsc.[/b]
DMurphyOut of curiosity, are additional components needed to knock down the upper Hz resonance in the Mag driver after you have hit your target 24db/oct with 4th order XO?Hi I'm not quite sure I understand your question. The "upper Hz resonance" is The what the lcr circuit is designed to eliminate. But in the process that circuit, in combination with the first series inductor, is enough to give you the desired 4th order acoustic roll off. No other components are needed. That was a major breakthrough in the design of the W18. The previous W17, and the aluminum L17 series both had a much more complex breakup mode that required more components.
