Monitor W690 Crossover Design |
Monitor W690 Crossover Design
Vented
2 way System Designed for Dan Marx by BobM9 Option 1 Partial Baffle Step Compensation XO Topology and Values: The lowpass is a standard 2^{nd} order electrical yielding a 4^{th} order target response. The original zobel was found not to be needed. The highpass is a third order electrical filter yielding a 4^{th} order target response. The L pad is used for ease of manual adjustment of tweeter padding. This is a very minimal XO topology for a 4^{th} order target, however it does yield a good response with these drivers. The XO point was 2200 Hz, however the optimizer raised the XO point slightly. XO Values: The component values have been rounded to match readily available component values. R2 and R6 is the DCR of the inductor coil. Predicted
Response Curve Option 1:
The option 1 curve above represents about 4 dB of baffle step compensation with the expectation of some room reinforcement on the low end. Over system sensitivity is 86.5 dB. The response curve is +/- 2.5 dB from 200 – 20k Hz. The reversed polarity null is showing about a 10 dB dip. While we are guessing at the relative offset of the drivers at 20mm, it should be relatively close. Impedance
Phase
As you can see the impedance does not drop below 7 Ohms. This will be an easy load for almost any amplifier. The impedance phase reaches its minimum of –60 degrees at 2k Hz and is otherwise unremarkable... Complete Baffle Step Compensation XO Topolgy
and Values:
Predicted
Response Option 2:
Overall a very good frequency response. I did not
compensate for the gentle hump centered at 450 Hz due to the fact that
this is modeled data. Impedance Phase:
Nearly identical to option 1. Polar response at Crossover:
Typical 4^{th} order LR lobing pattern. |
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This page last updated on
June 02, 2004.