Passive crossover designer
Component values from RESEARCH §6.
Linkwitz-Riley: −6 dB at fc, in-phase, flat summed response — the popular 2-/4-way choice.
Design against measured data (FRD / ZMA import)
Paste a driver’s measured impedance export (ZMA: frequency, |Z|, optional phase) from REW, ARTA/LIMP, DATS, CLIO, OmniMic or HolmImpulse. Any delimiter (space / tab / comma / semicolon) and * # // ; comment headers are auto-detected. The filter component values are then computed against the real |Z| at the crossover frequency instead of the nominal load. Imported data is treated as user-measured, not manufacturer-verified.
Optimize crossover (numeric goal-seek)
A deterministic, gradient-free optimizer searches the crossover frequency and per-driver level to best match a target summed response — a flat in-band response by default, or your imported measured FRD when pasted below. It is a pure layer on the RESEARCH §6 engine; results are reproducible. Paste an acoustic FRD target (frequency, SPL, optional phase) to optimize against measured data.
Optimizes from the current fc 2500 Hz / Linkwitz-Riley 4thorder. “Apply” copies the optimized fc into the design above.
Woofer — low-pass
| Part | Value | Nearest std |
|---|---|---|
| L3 series | 0.96 mH | ≈ 1 mH |
| C3 shunt | 12.66 µF | ≈ 0.68 + 12 µF ∥ |
| L4 series | 0.48 mH | ≈ 0.47 mH |
| C4 shunt | 2.81 µF | ≈ 0.12 + 2.7 µF ∥ |
Tweeter — high-pass
| Part | Value | Nearest std |
|---|---|---|
| C1 series | 4.22 µF | ≈ 0.33 + 3.9 µF ∥ |
| L1 shunt | 0.32 mH | ≈ 0.33 mH |
| C2 series | 8.44 µF | ≈ 0.22 + 8.2 µF ∥ |
| L2 shunt | 1.44 mH | ≈ 1.5 mH |
Per-driver & summed response (flat resistive load)
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Auxiliary networks
Zobel
Rz 6.0 Ω · Cz 13.89 µF
L-pad (dB, Z)
Rs 2.95 Ω · Rsh 13.68 Ω
Baffle step (cm)
f 507 Hz · L 1.78 mH
More topologies & tools
Starting values — all assume a flat, resistive load (RESEARCH §6). Verify and refine against measured FRD/ZMA.
Series 2-way (2nd order, Linkwitz-Riley)
Drivers in series across the amp, reactive parts in parallel with each driver. Values equal the parallel design; the 1st-order series network sums flat at all frequencies. Uses fc 2500 Hz / Woofer Z 8 Ω.
| Part | Value |
|---|---|
| L_w (woofer arm) | 1.02 mH |
| C_t (tweeter arm) | 3.98 µF |
| C_w (∥ woofer) | 3.98 µF |
| L_t (∥ tweeter) | 1.02 mH |
2.5-way (.5-woofer baffle-step roll-off)
The .5 woofer is low-passed at the baffle-step frequency (115/Wb) so both woofers play below the step — built-in baffle-step compensation. Baffle width from the box above (22.7 cm).
LP corner 507 Hz · series L 2.51 mH
Notch / contour networks
Parallel L‖C‖R trap (series in path) tames a breakup peak; series L–C–R trap (shunt) contours the response or conjugates an impedance peak. Centre = 1/(2π√(LC)). Set f0/depth from the measured peak.
Parallel notch (BW −1333 Hz)
| Part | Value |
|---|---|
| L (∥) | 0.23 mH |
| C (∥) | 6.90 µF |
| R (∥) | 17.30 Ω |
Series notch / contour
| Part | Value |
|---|---|
| L (series trap) | 0.95 mH |
| C (series trap) | 1.66 µF |
| R (series trap) | 8.00 Ω |
Air-core inductor (Wheeler)
Single-layer solenoid turns / wire length / DCR for a target inductance (Wheeler 1928, ~1% for a reasonably long coil). High turn count or DCR ⇒ use thicker wire or a multilayer winding.
1907 turns · 2461.0 mm long · 157.47 m wire · DCR 2.074 Ω
Reverse mode — components → response
Enter the components you actually have (a high-pass series cap, optional shunt inductor) and a driver load; the chart is the exactresponse of that ladder driven by an ideal source — the honest “what your parts really do”, including effects the textbook forms idealize away.
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Crossover parts
| Part | Qty | Est. | Buy |
|---|---|---|---|
| 1 mH air-core inductor (L3 series) | 1 | $6 | Parts Express → |
| 12 µF film capacitor (C3 shunt) | 1 | $3 | Parts Express → |
| 0.47 mH air-core inductor (L4 series) | 1 | $6 | Parts Express → |
| 2.7 µF film capacitor (C4 shunt) | 1 | $3 | Parts Express → |
| 3.9 µF film capacitor (C1 series) | 1 | $3 | Parts Express → |
| 0.33 mH air-core inductor (L1 shunt) | 1 | $6 | Parts Express → |
| 8.2 µF film capacitor (C2 series) | 1 | $3 | Parts Express → |
| 1.5 mH air-core inductor (L2 shunt) | 1 | $6 | Parts Express → |
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