# Speaker crossover timing: where the values come from

Researched 2026-10-18. Values in js/speaker-timing.js. A crossover that sums flat still rotates phase, delaying the lower driver relative to the upper one; the renderer applies that rotation as an all-pass (js/room.js, crossoverAllpass). First-order designs and linear-phase DSP add none. "assumed" means the order (and sometimes the frequency) is not published and is our estimate from the measured step response and driver polarity.

| Speaker | Crossovers | Linear phase | Status | Basis |
| --- | --- | --- | --- | --- |
| KEF LS50 Meta (neutral coaxial) | 2100 Hz LR4 |  | assumed | KEF publishes 2.1 kHz but not the order; Stereophile found both drivers in positive polarity with the tweeter leading |
| Revel F328Be (Harman-tradition floorstander) | 240 Hz LR4, 2100 Hz LR4 |  | assumed | Revel describes "traditional high-order" slopes; exact order unpublished |
| KEF Blade 2 Meta (coaxial point-source tower) | 450 Hz LR2, 2200 Hz LR2 |  | assumed | Stereophile: lower-order slopes, tweeter and midrange inverted |
| Polk Audio Monitor 40 Series II (budget bookshelf) | 2300 Hz LR2 |  | cited | Polk: 2nd-order crossover (from the original Monitor 40 specifications) |
| Rogers LS3/5A (BBC monitor) | 3000 Hz LR2 |  | assumed | BBC design at 3 kHz; Stereophile found the tweeter inverted, typical of a 2nd-order network |
| Harbeth Monitor 30.0 (BBC lineage) | 3000 Hz LR2 |  | assumed | Frequency unpublished; Stereophile: tweeter inverted, "neither time-coherent nor time-coincident" |
| Bowers & Wilkins 805S (tweeter-on-top) | 4000 Hz LR4 |  | assumed | Stereophile measured "steep acoustic slopes" on the Nautilus 805 predecessor |
| Dynaudio Special Forty (Danish bookshelf) | 2000 Hz first |  | cited | Dynaudio: first-order at 2 kHz |
| Wilson Audio TuneTot (luxury compact) | 2500 Hz LR2 |  | assumed | Frequency and order unpublished; Wilson adjusts driver timing with the rake angle |
| Vandersteen Treo CT (time-coherent) | 80 Hz first, 900 Hz first, 5000 Hz first |  | cited | Vandersteen: first-order, time and phase correct; Stereophile measured a near time-coincident step |
| JBL 4349 (horn studio monitor) | 1500 Hz LR4 |  | assumed | JBL publishes 1.5 kHz but not the order |
| Klipsch Heresy IV (horn-loaded heritage) | 850 Hz LR4, 4500 Hz LR4 |  | assumed | Klipsch publishes 850 Hz and 4.5 kHz with "steep" slopes; order unpublished |
| Zu Audio Method (high-efficiency) | 10000 Hz first |  | assumed | Full-range woofer with no low-pass; only the tweeter is high-passed |
| Magnepan LRS (planar dipole) | 2000 Hz first |  | assumed | Frequency unpublished; Stereophile measured a time-coincident step |
| Quad ESL-57 (original electrostatic) | 600 Hz first |  | assumed | Simple passive network between the bass panels and treble strip; no measured step |
| Bose 901 Series V (direct/reflecting) | none |  | cited | Nine full-range drivers, no crossover |
| Linkwitz LXmini (omnidirectional DIY) | 700 Hz LR2 |  | cited | Linkwitz: LR2 at 700 Hz in DSP |
| Kii Three (active cardioid) | 220 Hz LR4, 2500 Hz LR4 | yes | cited | DSP; "Exact" (linear-phase) mode, which Stereophile measured as time-coincident |
| Dutch & Dutch 8C (active cardioid) | 100 Hz LR4, 1250 Hz LR4 | yes | cited | Dutch & Dutch: 4th-order Linkwitz-Riley, linear phase |
| Genelec 8351B (active coaxial studio monitor) | 320 Hz LR4, 2800 Hz LR4 |  | assumed | Genelec publishes the frequencies; slopes unpublished and only partly phase-corrected |
| JBL M2 (reference studio monitor) | 800 Hz LR4 |  | assumed | JBL publishes 800 Hz; DSP slopes unpublished |
| Wharfedale Linton 85th Anniversary (heritage three-way) | 630 Hz LR2, 2400 Hz LR2 |  | assumed | Wharfedale publishes 630 Hz and 2.4 kHz; order unpublished |
| JBL 4367 (big-box horn studio monitor) | 700 Hz LR4 |  | assumed | JBL publishes 700 Hz; order unpublished |
| Audio First Designs Cadentia 3 (kit three-way) | 430 Hz LR2, 2000 Hz LR2 |  | cited | Audio First Designs publishes 430 Hz and 2 kHz. Order fitted to the designer's measured on-axis phase: excess phase (measured minus minimum phase, after removing the 2.96 ms travel time) against the simulator's all-pass for each combination of first-order, LR2, LR4 and LR8. LR2 at both fits within ±6° from 50 Hz to 6 kHz (RMS 1.4° over 200 Hz–6 kHz; next best 6–12°). The method recovered a synthetic LR4 + LR2 response to 0.7°. Above about 7 kHz the phase can't be unwrapped reliably |
| Audio First Designs Fidelia (kit two-way) | 1560 Hz BW3 |  | cited | Audio First Designs' specification, quoted by Erin's Audio Corner: 1,560 Hz, "3rd-order acoustical". The Butterworth alignment is our assumption (the order is published, the alignment isn't) |
| Neumann KH 120 II (compact active studio monitor) | 1700 Hz LR8 | yes | cited | Neumann's specification: crossover 1,700 Hz at 48 dB/octave; FIR phase correction, linear phase from 120 Hz to 16 kHz (±45°). The Linkwitz-Riley alignment is our assumption |
| Pi Speakers four π (15-inch two-way with a horn) | 1250 Hz LR4 |  | assumed | Not on Pi's web pages (its crossover document is a PDF download; a search found no stated figure). Frequency estimated from Pi's vertical measurements, where the two drivers interfere: the deepest dips are at 1.1–1.4 kHz, 20° below and 30–40° above. Order unpublished (LR4, our choice) |
| Klipsch La Scala AL5 (fully horn-loaded three-way) | 450 Hz LR4, 4500 Hz LR4 |  | assumed | Klipsch's specification sheet (2018): 450 Hz and 4.5 kHz; order unpublished (LR4, our choice). Stereophile measured fairly sharp slopes and the upper crossover nearer 4 kHz. The horns' different lengths spread the drivers' arrivals: the tweeter first, the midrange 1.5 ms later, the woofer 2 ms after that (Stereophile's step response); the simulator models the crossover's phase, not these delays |
| Arendal 1610 Slim 8 (sealed on-wall three-way) | 340 Hz LR4, 2700 Hz LR4 |  | assumed | Arendal's specification, as quoted in Audio Science Review's review: 340 Hz and 2.7 kHz; order unpublished (LR4, our choice) |
| Aperion Novus N6SR (slim on-wall two-way) | 3000 Hz LR4 |  | assumed | Aperion's specification, as quoted by Erin's Audio Corner: 3 kHz; order unpublished (LR4, our choice) |
| DeVore Orangutan O/96 (wide-baffle high-efficiency) | 2400 Hz LR4 |  | assumed | Hi-Fi News places the crossover near 2.4 kHz; order unpublished. Stereophile: both drivers in positive polarity, the tweeter's step leading the woofer's |

## Pages

- Stereophile measurements: LS50 Meta, Blade Two Meta, Harbeth 30.2, Special Forty, Magnepan LRS, Kii Three, Vandersteen Treo, Dutch & Dutch 8c, LS3/5a (1989 and Falcon), B&W Nautilus 805 (https://www.stereophile.com/content/<model>-loudspeaker-measurements)
- Manufacturers: https://www.genelec.com/8351b, https://jblpro.com/en/products/m2, https://linkwitzlab.com/LXmini/Introduction.htm, https://www.soundandvision.com/content/jbl-4349-2-way-loudspeaker-review-specs, https://www.neumann.com/en-en/products/monitors/kh-120-ii/ (Data & Diagrams)
- Erin's Audio Corner: Bose 901 (rear-driver arrival), Treo CT, LXmini; Wharfedale Linton 85, JBL 4367 and Audio First Designs Fidelia (manufacturer specifications quoted in the reviews)
- DeVore O/96: Stereophile measurements and Hi-Fi News lab report
- Klipsch La Scala AL5: https://www.stereophile.com/content/klipsch-la-scala-al5-loudspeaker-measurements and Klipsch's specification sheet, https://d2um2qdswy1tb0.cloudfront.net/product-specsheets/La-Scala-2018-Spec-Sheet-v01.pdf
- Pi Speakers four π: https://pispeakers.com/Measurements/fourPi.html (vertical off-axis graphs)
- Weak sources: Polk forum copy of Monitor 40 specs