Twiggy10

ENCLOSURE RECOMMENDATIONS: Twiggy10X8-475A
Driver: Twiggy10X8-475A (Twiggy10) — 10" Ultra-Shallow Subwoofer
Key T/S: Fs=40.7Hz, Qts=0.33, Vas=14.57L, Sens=87dB 1W/1m
Power: AES 150W / Cont 300W / Peak 600W
Xmax=10.06mm (one-way linear), Xmech=18.06mm
Sd=305.4cm², Bl=19.24T·m, Re=3.5Ω (4-ohm nominal), Mms=138.3g
Voice Coil: 2" CCAW on Kapton former (28.12mm extended winding height)
Magnet: Neodymium (inside slug) | Basket: Steel
Cone: Glass fiber honeycomb composite | Surround: Rubber
Spider: Nomex
MOUNTING DEPTH: 80 mm
Volume Displacement (Vd): 307 cc
NOTE: The Twiggy10 brings the proven Twiggy ultra-shallow concept to
a 10-inch platform. The extended voice coil architecture (28.12 mm
winding height) delivers exceptional linear excursion (10.06 mm) from
a driver only 80 mm deep — roughly half the mounting depth of a
conventional 10" woofer. The low Qts (0.33) and strong neodymium
motor (Bl=19.24 T·m) combined with the glass fiber honeycomb cone
provide controlled, low-distortion bass from extremely compact and
shallow enclosures. This driver is uniquely suited to space-restricted
applications: under-sofa subwoofers, in-wall/in-ceiling systems,
automotive installations, slim furniture-integrated audio, and
shallow line array bass sections, as well as conventional compact
hi-fi subwoofers where the shallow depth enables creative form factors.
CABINET DEPTH REFERENCE:
  Driver mounting depth:        80 mm
  Minimum internal depth:       ~95 mm (driver + rear clearance)
  With 15 mm walls:             ~125 mm total external depth (~5")
This means a complete subwoofer cabinet can be built under 13 cm
(5 inches) deep — thin enough to slide under most sofas, mount
flush in a standard wall cavity, or fit under a car seat.
  SEALED ENCLOSURES — BY APPLICATION
The low Qts (0.33) produces remarkably compact sealed volumes for a
10" driver. Room gain and boundary reinforcement play a major role
in all shallow-mount applications, so estimated in-room response
is provided for each alignment.
  UNDER-SOFA / FURNITURE-INTEGRATED
These alignments prioritize extreme compactness. The elevated Qtc
values are intentional — placement under a sofa or against a wall
provides substantial boundary reinforcement (+6–10 dB below 80 Hz)
that compensates for the high fc and produces satisfying in-room
bass extension.
  a) SEALED — Ultra-Compact (Qtc ≈ 1.0)
     Net Volume: 1.8 liters
     System Resonance (fc): 123 Hz
     Qtc: 1.0
     Anechoic -3dB: ~123 Hz
     Estimated in-room -3dB: ~50–60 Hz (under-sofa placement)
     Cabinet face (at 95mm depth): ~14 × 14 cm (tiny!)
     Notes: The smallest practical sealed enclosure for the
     Twiggy10. The high fc (123 Hz) looks alarming in anechoic
     terms, but under-sofa and against-wall placement provides
     massive boundary reinforcement. Combined with DSP bass EQ
     (shelving boost below 100 Hz), this configuration produces
     surprisingly deep and satisfying bass from an enclosure
     barely larger than the driver itself. The broad resonance
     peak at fc provides a natural bass lift that works with,
     rather than against, the room acoustics. Ideal for hidden
     subwoofers where invisibility is the primary requirement.
  b) SEALED — Compact (Qtc ≈ 0.85)
     Net Volume: 2.6 liters
     System Resonance (fc): 105 Hz
     Qtc: 0.85
     Anechoic -3dB: ~105 Hz
     Estimated in-room -3dB: ~45–55 Hz (under-sofa placement)
     Cabinet face (at 95mm depth): ~17 × 17 cm
     Notes: Slightly larger than ultra-compact but still very
     small. The Qtc of 0.85 provides a smooth, warm response
     with less peaking than Qtc=1.0. Under-sofa placement extends
     effective bass well below 60 Hz. A good balance between
     compactness and response quality for hidden subwoofers.
     *** RECOMMENDED FOR UNDER-SOFA / HIDDEN INSTALLATIONS ***
  AUTOMOTIVE / SHALLOW-MOUNT
These alignments are sized for under-seat, door panel, or shallow
trunk installations where the 80 mm driver depth is a critical
advantage. Vehicle cabin gain provides +10–15 dB of reinforcement
below 60 Hz.
  c) SEALED — Automotive Compact (Qtc ≈ 0.85)
     Net Volume: 2.6 liters
     System Resonance (fc): 105 Hz
     Qtc: 0.85
     Estimated in-cabin -3dB: ~35–40 Hz (with cabin gain)
     Notes: Extremely compact sealed enclosure for under-seat
     installation. The vehicle cabin's massive acoustic gain
     at low frequencies transforms the 105 Hz anechoic fc into
     effective in-cabin response well below 40 Hz. The Twiggy10's
     80 mm depth fits under most vehicle seats with clearance
     to spare. The 4-ohm impedance is standard for automotive
     amplifiers.
  d) SEALED — Automotive Standard (Qtc ≈ 0.707)
     Net Volume: 4.1 liters
     System Resonance (fc): 87 Hz
     Qtc: 0.707
     Estimated in-cabin -3dB: ~28–35 Hz (with cabin gain)
     Notes: Butterworth alignment providing flat anechoic response.
     With cabin gain, in-car bass extends into the upper 20s Hz —
     genuine infrasonic territory from a shallow-mount 10". A
     4.1-liter enclosure at 95 mm depth requires a face of only
     ~21 × 21 cm, easily fitting behind a rear seat panel or in
     a shallow trunk enclosure.
     *** RECOMMENDED FOR AUTOMOTIVE ***
  IN-WALL / IN-CEILING
Standard wall cavities (89–140 mm depth for 2×4 and 2×6 framing)
easily accommodate the Twiggy10's 80 mm mounting depth. The wall
cavity itself forms part of the sealed enclosure volume, though
back-box isolation is recommended for consistent performance.
  e) SEALED — In-Wall Standard (Qtc ≈ 0.707)
     Net Volume: 4 liters (sealed back-box)
     System Resonance (fc): 87 Hz
     Qtc: 0.707
     Estimated in-room -3dB: ~50–58 Hz (flush wall mount)
     Notes: A sealed back-box of approximately 4 liters behind
     the driver provides Butterworth-class response. The flush
     wall mount provides half-space loading (+3 dB sensitivity
     boost) and boundary reinforcement. Well-suited for
     distributed in-wall subwoofer systems where multiple
     Twiggy10 units supplement in-wall/in-ceiling full-range
     speakers.
  f) SEALED — In-Wall Extended (Qtc ≈ 0.6)
     Net Volume: 6 liters (sealed back-box)
     System Resonance (fc): 74 Hz
     Qtc: 0.60
     Estimated in-room -3dB: ~42–50 Hz (flush wall mount)
     Notes: Larger back-box providing deeper bass extension.
     The overdamped response rolls off gradually, integrating
     smoothly with room acoustics. Well-suited for dedicated
     home theater in-wall subwoofer installations where deeper
     bass is required from a single driver location.
  STANDARD HI-FI SUBWOOFER
For conventional free-standing subwoofer cabinets where the shallow
depth enables slim, furniture-friendly form factors (e.g., a
subwoofer that stands upright like a thin panel or slides into a
bookshelf space).
  g) SEALED — Butterworth (Qtc ≈ 0.707)
     Net Volume: 4 liters
     System Resonance (fc): 87 Hz
     Qtc: 0.707
     Anechoic -3dB: ~87 Hz
     Estimated in-room -3dB: ~55–62 Hz (corner or near-wall)
     Cabinet (at 95mm depth): ~21 × 21 cm face, 12.5 cm deep
     Notes: Maximally flat sealed alignment. Room gain extends
     usable bass into the upper 50s Hz. A very slim, compact
     subwoofer that can stand upright beside furniture or mount
     on a wall. The Twiggy10's 307 cc displacement provides
     meaningful output at these frequencies.
  h) SEALED — Extended (Qtc ≈ 0.6)
     Net Volume: 6 liters
     System Resonance (fc): 74 Hz
     Qtc: 0.60
     Anechoic -3dB: ~74 Hz
     Estimated in-room -3dB: ~46–54 Hz (corner or near-wall)
     Cabinet (at 95mm depth): ~25 × 25 cm face, 12.5 cm deep
     Notes: Larger sealed enclosure with better bass extension.
     The overdamped alignment integrates well with room acoustics
     for natural-sounding bass. Still a very slim form factor.
     *** RECOMMENDED FOR FREE-STANDING HI-FI SUB ***
  i) SEALED — Large (Qtc ≈ 0.5)
     Net Volume: 10 liters
     System Resonance (fc): 64 Hz
     Qtc: 0.50
     Anechoic -3dB: ~64 Hz
     Estimated in-room -3dB: ~40–48 Hz (corner or near-wall)
     Cabinet (at 95mm depth): ~32 × 32 cm face, 12.5 cm deep
     Notes: Largest practical sealed alignment. Deep bass
     extension with heavily overdamped response. In-room with
     corner placement, usable response approaches 40 Hz —
     genuine subwoofer territory from a slim cabinet only
     12.5 cm deep.
  VENTED / PASSIVE RADIATOR ENCLOSURES
Vented enclosures extend the low-frequency response significantly
beyond what sealed can achieve. However, the shallow cabinet depth
makes conventional round ports impractical (port lengths of 500–
630 mm are required). Two practical solutions are provided:
folded slot ports and passive radiators.
PORT NOTE: Round port lengths exceed 500 mm at all tuning frequencies,
which is impractical for shallow cabinets. Slot ports (200 × 30 mm
cross-section) can be folded internally within the shallow cabinet
geometry. Passive radiators eliminate the port entirely and are the
preferred solution for shallow-mount vented enclosures.
  j) VENTED — Compact
     Net Volume: 12 liters
     Tuning (Fb): 45 Hz
     Est. -3dB: 41 Hz
     HP Filter: 35 Hz (24dB/oct recommended)
     Slot Port (200×30mm): ~672mm long (folded internally)
     Port Velocity (slot): 14.5 m/s
     Cabinet (at 95mm depth): ~36 × 36 cm face, 12.5 cm deep
     Notes: Compact vented alignment reaching into the low
     40s Hz anechoic. With room gain, in-room response extends
     below 30 Hz. Requires folded slot port or passive radiator.
  k) VENTED — Balanced
     Net Volume: 14 liters
     Tuning (Fb): 40 Hz
     Est. -3dB: 34 Hz
     HP Filter: 30 Hz (24dB/oct recommended)
     Slot Port (200×30mm): ~734mm long (folded internally)
     Port Velocity (slot): 12.9 m/s
     Cabinet (at 95mm depth): ~38 × 38 cm face, 12.5 cm deep
     Notes: Excellent balance of extension and cabinet size.
     Anechoic -3 dB at 34 Hz is genuine deep bass from a slim
     panel cabinet. With room gain, usable response approaches
     the mid-20s Hz.
     *** RECOMMENDED VENTED ALIGNMENT ***
  l) VENTED — Extended
     Net Volume: 17 liters
     Tuning (Fb): 34 Hz
     Est. -3dB: 29 Hz
     HP Filter: 24 Hz (24dB/oct recommended)
     Slot Port (200×30mm): ~846mm long (folded internally)
     Port Velocity (slot): 10.9 m/s
     Cabinet (at 95mm depth): ~42 × 42 cm face, 12.5 cm deep
     Notes: Maximum extension, reaching below 30 Hz anechoic.
     Largest cabinet but still only 12.5 cm deep. Requires the
     longest folded port path — a passive radiator is strongly
     recommended for this alignment.
PASSIVE RADIATOR NOTE:
A passive radiator (PR) is the ideal partner for the Twiggy10 in
vented applications, especially in shallow enclosures where port
length is impractical. A matching shallow-profile 10" PR should have:
  - Sd approximately equal to the active driver (~305 cm²)
  - Mounting depth compatible with the shallow cabinet (~80 mm)
  - Tuning mass selected for the desired Fb (34–45 Hz)
  - Xmax equal to or greater than the active driver (≥10 mm)
A Twiggy10 + matching PR in a 12–17 liter shallow enclosure produces
a slim panel subwoofer (~12.5 cm deep) with genuine deep bass
extension to the low 30s Hz — a compelling product for modern
living spaces.
MULTI-DRIVER NOTE: The shallow form factor and compact sealed
volumes make it practical to use multiple Twiggy10 drivers in a
single shallow enclosure. Two Twiggy10 units in a 6–8 liter sealed
enclosure (3–4L per driver) produce +6 dB more output than a single
driver while maintaining the ultra-slim cabinet profile. This
distributed approach is particularly effective for in-wall systems
and slim soundbar-style subwoofers.