REFLECTOR AUDIO
SQUARE TWO Q1818 TECHNOLOGY CONTACT
T1 · HORN MOUTH 1.4″ CD — 1 kHz XO T2 · BANDPASS VENT 4 × 5″ LF
PLATE 01 — SQUARE TWO, ANECHOIC CHAMBER · RIGA
STAND-IN — PHOTOGRAPH PENDING
SQT · FREE FIELD · 1 m
REFLECTOR AUDIO — RIGA, LATVIA

Four woofers around a horn.

Square Two is a coaxial point source. Four 5-inch woofers vent through bandpass chambers in the face of a central horn, so a 320 mm enclosure radiates as a single source rather than a box with drivers in it.

01 — SPECIFICATIONSQUARE TWO — SQT
M-01
{{ bwLo }} Hz – {{ bwHi }} kHz
bandwidth (−6 dB)
M-02
{{ spl }} dB
max SPL (3% THD)
M-03
{{ pm }} dB
pair matching
02

Two instruments

Square Two (SQT)

POWERED TWO-WAY

Compact powered two-way. Coaxial horn, four 5″ woofers, 1 kHz phase-linear crossover. 320 mm enclosure, bass-reflex, convertible to sealed. Hypex Ncore amplification. Optional SQB bass system extends it to three-way, down to 16 Hz.

Q1818

REFERENCE SYSTEM

Impulse-corrected open-baffle reference system. Four 18-inch drivers and a compression driver in a baffleless coaxial array, with additional 18-inch subs. Approximately 10 kW of passively cooled Class D. Figure-of-eight radiation. Tuned in-room, per control room.

03
Built in Riga. Tuned in your room.
SQT · POWERED TWO-WAY

Square Two

A coaxial point source in a 320 mm enclosure.

A central 1.4-inch compression driver sits on the horn; four 5-inch woofers vent through bandpass chambers in the horn face around it. Their acoustic centres align, so the monitor behaves as one source through the 1 kHz crossover instead of two sources arguing about where the image sits. The crossover is phase-linear from about 200 Hz, corrected with IIR filters rather than FIR.

SPECIFICATION — READOUTSQT
Configuration
Powered two-way, coaxial horn — bass-reflex, convertible to sealed
Frequency range
40 Hz – 26 kHz (−6 dB)
Crossover
1 kHz, phase-linear from ~200 Hz (IIR, no FIR)
Drivers
4 × 5″ Eighteen Sound woofers · 1.4″ FaitalPRO compression driver
Directivity
120° > 600 Hz · 90° > 1 kHz · 50° > 2 kHz — horizontal = vertical
Max SPL
112 dB (3% THD) · 118 dB peak
Amplification
Hypex Ncore 2 × 125 W + 100 W · Sigma DSP
Pair matching
0.35 dB
Enclosure
320 × 345 × 325 mm · 19.4 kg
Bass extension
SQB system, optional — three-way, to 16 Hz · latency < 5 ms
REFLECTOR 320 345 DEPTH 325 mm · 19.4 kg T1 · COMPRESSION DRIVER 1.4″ — ON HORN AXIS T2 · BANDPASS VENT 4 × 5″ WOOFERS
FIG.01 — SQUARE TWO, FRONT ELEVATION · 320 × 345 × 325 mm · 19.4 kg · DRAWN STAND-IN, PHOTOGRAPH PENDING
SQT-FR-001 — ON-AXIS RESPONSE · 1 m FREE FIELD REL dB · SMOOTHED 1/12 OCT +10 0 −10 −20 −30 −40 20 50 100 200 500 1k 2k 5k 10k 20k 40k FREQUENCY, Hz — LOG 40 Hz – 26 kHz (−6 dB) 1.000 kHz SECTION XO · −6 dB
FIG.02 — ON-AXIS FREQUENCY RESPONSE · LF / HF SECTIONS AND SUM · XO 1.000 kHz · −6 dB AT 40 Hz / 26 kHz · DRAWN STAND-IN, MEASUREMENT PENDING
SQT-POL-001 — BEAMWIDTH 30° 60° 90° 120° 150° 180° 0 dB −6 −12 −18 120° > 600 Hz 90° > 1 kHz 50° > 2 kHz −6 dB PER RING · NORMALISED ON AXIS
FIG.03 — DIRECTIVITY, −6 dB BEAMWIDTH · HORIZONTAL = VERTICAL
HYPEX NCORE 2 × 125 W + 100 W SIGMA DSP IIR FILTER ENGINE SQT-AMP · REV C NCORE — 2 × 125 W + 100 W SIGMA DSP
PLATE 02 — AMPLIFIER MODULE · HYPEX NCORE · SIGMA DSP · DRAWN STAND-IN, PHOTOGRAPH PENDING
PRINCIPLES 01–05

Technology

D-01
01

Coaxial point source

Four low-frequency drivers vent around a central horn. One acoustic origin instead of two; the image holds as you move.

90° D-02
02

Horn loading

Controlled directivity and high sensitivity, so the compression driver works in a smaller, more linear part of its excursion. Horizontal and vertical dispersion are matched.

φ 1 kHz D-03
03

Phase-linear crossover

The 1 kHz crossover is corrected in the digital domain from ~200 Hz using IIR filters (bell, shelf and all-pass; no FIR), so time-domain accuracy is a design target, not a by-product of the response.

120° 600 Hz 90° 1 kHz 50° 2 kHz D-04
04

Controlled directivity

The −6 dB beamwidth narrows predictably with frequency — 120° above 600 Hz, 90° at 1 kHz, 50° above 2 kHz — so the room is excited with the same balance you hear on axis.

REFLEX SEALED + SQB 16 Hz D-05
05

Convertible loading

Bass-reflex out of the box, convertible to sealed, with an optional three-way bass system reaching 16 Hz. The monitor is matched to its room, not to a house sound.

ATTRIBUTION

The baffle-free, figure-of-eight story belongs to the Bespoke line (P15/E15) and the Q1818 reference system — not to Square Two, which is a bass-reflex coaxial design.

We are not voicing a loudspeaker. We are handing back the recording with its temporal and spatial information intact.
Reflector Audio Design, SIA · Riga · New York · Los Angeles