LF
Woofer
15"
152FIND
Code: 152FINDX8-333
Woofer/15inch/Ferrite/Paper/800W/8ohm
Key Features
- EXTENDED LOW FREQUENCY RESPONSE
- Carbon fiber reinforced cone
- High excursion rubber surround
Quick Specs
Impedance
8 Ω
Program Power
1600 W
Sensitivity
95.62 dB
Fs
37.00 Hz
Magnet
Ferrite
Voice Coil
76 mm
Design Notes
The 152FIND-333 is a high efficiency, (96 dB 1watt / 1 meter) 15-inch woofer with linear frequency response characteristics and high power handling capability. The 152FIND-333 uses a lightweight carbon fiber loaded cone assembly along with a high excursion rubber surround. This combination greatly improves low-frequency response and provides great level of control over the moving cone at high excursion levels. We have designed a lightweight surround, using our own rubber compound. As the result, the SPL is not compromised and the woofer can be used in professional audio applications, where high amounts of low frequencies are required.
Power Handling
At the core of the 152FIND-333 is it’s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 280C, well beyond the thermal requirements of modern professional audio systems.
The 152FIND-333 cone is extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.
Power Handling
At the core of the 152FIND-333 is it’s voice coil technology featuring a composite Polyimide former material capable of withstanding peak temperatures in excess of 280C, well beyond the thermal requirements of modern professional audio systems.
The 152FIND-333 cone is extensively treated to withstand harsh environments and high humidity. Metal parts in the speaker assembly are coated for extreme weatherization protection.
Specifications
General Specs
Nominal Diameter
15"
Rated Impedance
8 Ohm
Magnet
Ferrite
Basket Material
Aluminum
Power Handling
AES Power
800 W
Continuous Power
1600 W
Peak Power
3200 W
Voice Coil
Diameter
76 mm
Winding Wire
CCAW
Former
Glass Fiber
Winding Height
19 mm
T/S Parameters
Resonant Frequency (Fs)
37.00 Hz
Re
4.60 \u2126
Qes
0.460
Qms
10.20
Qts
0.440
Vas
119.00 liters
Sd
804.00 cm\u00B2
Mms
140.00 grams
Rms
3.19
Cms
0.1300
Bl
18.40 T\u00B7m
Le
0.550 mH
Sensitivity
95.62 dB
Design Details
Surround Material
NBR
Cone/Dome Material
Paper CF
Spider
Nomex
T-Plate
10 mm
Xmax (peak)
4.5 mm
Xmech
14.5 mm
Overall Diameter
392.00 mm
Bolt Circle Diameter
375.00 mm
Baffle Cutout Dia.
360.00 mm
Mounting Holes
8
Depth (flange to rear)
143.00 mm
Net Weight
9.00 kg
Ordering Codes
Product Code
152FINDX8-333
Downloads
Frequency Response & Impedance
2D Drawing
Technical Summary
The 152FINDX8-333 is a 15-inch professional mid-bass woofer designed for high-SPL two-way PA enclosures, fixed installation systems, and outdoor applications requiring extended low-frequency performance and high mechanical durability. The driver uses a 76 mm (3-inch) CCAW voice coil wound on a Polyimide former rated to 280°C, delivering 800 W AES and 1600 W continuous power handling at 8 ohms. With a Ferrite motor producing a Bl of 18.4 T·m and a deliberately elevated moving mass of 140 g, the -333 is tuned to a lower resonant frequency of 37 Hz compared to other drivers in the 152FIND platform — a design choice that prioritizes bass extension and displacement control over peak sensitivity. The result is a measured sensitivity of 95.62 dB (1 W/1 m), 3.4 dB below the higher-sensitivity -115 variant, with the trade-off being usable -3 dB output approximately 17 Hz lower. The voice coil inductance of Le=0.55 mH is significantly lower than competing 15-inch PA woofers of similar power class, reducing high-frequency inductance modulation distortion and preserving upper midrange clarity across the 50 Hz–1 kHz operating band at high displacement. The NBR rubber surround, produced from a REDCATT proprietary rubber compound, provides superior fatigue resistance, UV stability, ozone resistance, and compliance consistency compared to fabric surrounds under sustained high-excursion programme conditions, making the -333 the preferred choice for permanently installed outdoor systems and touring applications requiring extended service intervals.
The 152FINDX8-333 is optimized for vented (bass reflex) enclosures across a 50 to 110 litre net internal volume range, with tuning frequencies from 43 to 60 Hz. The compact 50 L alignment, tuned to 60 Hz, delivers -3 dB at approximately 58 Hz for high-output touring PA cabinets and column-format woofer sections; a 100 mm round port tube of 130 mm length is used, as the cabinet depth at this volume is insufficient for the slot port lengths generated by this tuning. The recommended 80 L standard alignment, tuned to 50 Hz, extends the -3 dB point to approximately 48 Hz, covering the full bass and lower midrange programme range from a standard professional two-way cabinet format; both a 100 mm round port (117 mm long, 14.5 m/s) and a 250×80 mm slot port (298 mm long, 5.7 m/s) are practical at this volume. The extended 110 L alignment at 43 Hz tuning achieves -3 dB at approximately 41 Hz — at the bass guitar open E fundamental — from a single 15-inch two-way enclosure, with slot port velocity of 4.9 m/s effectively eliminating turbulence noise across all drive levels. Port tube lengths decrease counter-intuitively as box volume increases across all three alignments (130 → 117 → 115 mm round), a product of the larger Vb more than compensating for the lower Fb, making port fabrication straightforward across the range.
The 152FINDX8-333 requires high-power professional amplification of 800–1600 W into 8 ohms, with DSP management mandatory including a 24 dB/octave high-pass filter at 45, 38, or 33 Hz depending on alignment. Below the tuning frequency, enclosure acoustic loading is removed and cone excursion rises rapidly; the Xprot of 20 mm provides a generous mechanical safety margin, but displacement-limiting in DSP is still essential at full programme power. The recommended operating bandwidth extends from approximately 40 Hz to 1.0–1.5 kHz; a 24 dB/octave low-pass crossover to a compression driver or high-frequency section at this frequency is standard for two-way system integration.
The 152FINDX8-333 is suited for: two-way touring PA enclosures requiring extended low-frequency performance and high mechanical durability from a 15-inch driver; permanently installed outdoor main speakers for amphitheatres, sports venues, festival sites, and theme parks where NBR rubber surround longevity is a primary service-life consideration; installed main speakers for theatres, houses of worship, and stadia where sub-bass coverage from the main enclosure is desirable; high-SPL club and venue systems operating at continuous programme levels with sustained high displacement; and cinema LF sections requiring bass guitar and low-drum fundamental reproduction without a supplementary subwoofer. Its combination of Fs=37 Hz, Le=0.55 mH, NBR rubber surround, and Polyimide former makes the -333 the acoustically deeper, mechanically more durable, and environmentally more robust variant within the 152FIND product platform.
The 152FINDX8-333 is optimized for vented (bass reflex) enclosures across a 50 to 110 litre net internal volume range, with tuning frequencies from 43 to 60 Hz. The compact 50 L alignment, tuned to 60 Hz, delivers -3 dB at approximately 58 Hz for high-output touring PA cabinets and column-format woofer sections; a 100 mm round port tube of 130 mm length is used, as the cabinet depth at this volume is insufficient for the slot port lengths generated by this tuning. The recommended 80 L standard alignment, tuned to 50 Hz, extends the -3 dB point to approximately 48 Hz, covering the full bass and lower midrange programme range from a standard professional two-way cabinet format; both a 100 mm round port (117 mm long, 14.5 m/s) and a 250×80 mm slot port (298 mm long, 5.7 m/s) are practical at this volume. The extended 110 L alignment at 43 Hz tuning achieves -3 dB at approximately 41 Hz — at the bass guitar open E fundamental — from a single 15-inch two-way enclosure, with slot port velocity of 4.9 m/s effectively eliminating turbulence noise across all drive levels. Port tube lengths decrease counter-intuitively as box volume increases across all three alignments (130 → 117 → 115 mm round), a product of the larger Vb more than compensating for the lower Fb, making port fabrication straightforward across the range.
The 152FINDX8-333 requires high-power professional amplification of 800–1600 W into 8 ohms, with DSP management mandatory including a 24 dB/octave high-pass filter at 45, 38, or 33 Hz depending on alignment. Below the tuning frequency, enclosure acoustic loading is removed and cone excursion rises rapidly; the Xprot of 20 mm provides a generous mechanical safety margin, but displacement-limiting in DSP is still essential at full programme power. The recommended operating bandwidth extends from approximately 40 Hz to 1.0–1.5 kHz; a 24 dB/octave low-pass crossover to a compression driver or high-frequency section at this frequency is standard for two-way system integration.
The 152FINDX8-333 is suited for: two-way touring PA enclosures requiring extended low-frequency performance and high mechanical durability from a 15-inch driver; permanently installed outdoor main speakers for amphitheatres, sports venues, festival sites, and theme parks where NBR rubber surround longevity is a primary service-life consideration; installed main speakers for theatres, houses of worship, and stadia where sub-bass coverage from the main enclosure is desirable; high-SPL club and venue systems operating at continuous programme levels with sustained high displacement; and cinema LF sections requiring bass guitar and low-drum fundamental reproduction without a supplementary subwoofer. Its combination of Fs=37 Hz, Le=0.55 mH, NBR rubber surround, and Polyimide former makes the -333 the acoustically deeper, mechanically more durable, and environmentally more robust variant within the 152FIND product platform.
Enclosure Recommendations
ENCLOSURE RECOMMENDATIONS: 152FINDX8-333
Driver: 152FINDX8-333 (152FIND-333) — 15" ferrite pro mid-bass woofer, 8 ohm
Key T/S: Fs=37Hz, Qts=0.44, Qes=0.46, Qms=10.2, Vas=119L, Sens=95.62dB
Power: AES 800W / Cont 1600W / Peak 3200W
Xmax=4.5mm (linear), Xmech=14.5mm, Xprot=20mm
Sd=804cm², Bl=18.4T·m, Le=0.55mH, Re=4.6Ω
Voice coil: 76mm (3"), CCAW winding, Polyimide former (280°C rated)
Cone: carbon fiber loaded paper, environmentally treated
Surround: NBR rubber (high-excursion compound, REDCATT formulation)
Spider: Nomex
Depth: 143mm | Baffle cutout: 360mm | Ferrite motor
COMPARISON NOTE — 152FIND-333 vs 152FIND-115:
The -333 variant shares the 15" platform and 76mm voice coil with the
-115 (see 152FINDX8-115_enclosure_output.txt) but is tuned significantly
differently. The -333 carries a heavier moving mass (Mms=140g vs 95.6g),
producing a lower Fs of 37Hz (vs 44Hz) and a reduced sensitivity of
95.62dB (vs 99.03dB) — a deliberate trade-off favouring extended low-
frequency reach and high-excursion control over raw efficiency. The NBR
rubber surround replaces the fabric triple-roll, providing superior
resistance to fatigue, UV exposure, and ozone at large cone displacements.
Lower voice coil inductance (Le=0.55mH vs 0.98mH) reduces high-frequency
phase shift and inductance modulation distortion, broadening the usable
upper bandwidth. The -333 is the preferred choice when low-frequency
extension, high displacement control under sustained drive, and outdoor
durability are prioritized over maximum sensitivity.
ENCLOSURE TYPE RATIONALE:
Qts=0.44 is within the upper range of standard vented alignment for a
15-inch professional woofer. Vented (bass reflex) enclosures are the
primary recommendation: the driver's Fs=37Hz and Vas=119L allow tuning
down to 43Hz in a 110L enclosure, reaching bass guitar open E and
kick drum sub-fundamental. Sealed alignments are omitted — the Butterworth
sealed alignment at Qts=0.44 requires approximately 80L and produces
fc≈60Hz, which does not justify the efficiency penalty of a sealed box
at this Qts level when vented options provide -3dB at 41–58Hz.
DISPLACEMENT:
Vd = Sd × Xmax = 804 cm² × 0.450 cm = 361.8 cm³ (peak, one-way)
WEATHERIZATION:
The NBR rubber surround (REDCATT proprietary compound) provides high
resistance to ozone, UV, moisture, and temperature cycling without
degradation in compliance or fatigue life. The carbon fiber loaded paper
cone is treated against humidity. Metal basket components are coated for
weatherization protection. The -333 surround compound is specifically
designed for applications requiring extended outdoor service life.
VENTED (BASS REFLEX) ALIGNMENTS
Ports: 100mm diameter round tube (Ap=7.854×10⁻³ m²)
OR 250×80mm slot port (Ap=2.000×10⁻² m²)
Port velocity limit (pro PA): ≤22 m/s
Port velocity limit (install): ≤17 m/s
Note on slot port for Alignment A: the 331mm slot length is impractical
in a 50L compact cabinet (internal depth typically 230–270mm). Round port
or a smaller slot (200×60mm) is recommended for the compact alignment.
200×60mm slot (Ap=0.012 m²): length=497mm at Fb=60Hz — impractical.
Recommendation: use 100mm round port for Alignment A only.
ALIGNMENT A — COMPACT (50 L net internal)
Box volume: 50 L (net internal)
Tuning freq (Fb): 60 Hz
Round port: 100mm dia × 130mm long
Port velocity: 17.4 m/s (peak, at Xmax)
System f-3dB: ~58 Hz
HP filter: 45 Hz, 24 dB/oct DSP (mandatory)
Max SPL (800W, 1m): ~125 dB
Application: Compact two-way touring PA cabinet, outdoor column
speaker woofer section, high-SPL stage monitor.
Notes: The compact high-output alignment. Fb=60Hz (1.62×Fs) keeps the
tuning well above the driver's lower resonance, maximizing cone
control and output in the 60Hz–1kHz midbass range. The 50L
cabinet is the smallest practical enclosure for the -333 at this
Qts; in compact touring formats (approx. 510×480×240mm external)
the single 100mm round port fits any panel orientation. Port
velocity of 17.4 m/s is within pro PA limits; a flared port end
is recommended. At full power the NBR rubber surround provides
stable compliance under sustained high-excursion drive conditions
that would cause fatigue in fabric surrounds after extended use.
ALIGNMENT B — STANDARD PA (80 L net internal)
Box volume: 80 L (net internal)
Tuning freq (Fb): 50 Hz
Round port: 100mm dia × 117mm long
Port velocity: 14.5 m/s (peak, at Xmax)
Slot port: 250×80mm × 298mm long
Port velocity: 5.7 m/s (peak, at Xmax)
System f-3dB: ~48 Hz
HP filter: 38 Hz, 24 dB/oct DSP (mandatory)
Max SPL (800W, 1m): ~125 dB
Application: Two-way touring PA cabinet with extended bass, installed
main speaker (theatre, stadium, HoW, outdoor arena),
flyable touring enclosure, large-format PA top box.
Notes: The recommended general-purpose alignment. At 48Hz -3dB the driver
covers the full music programme including bass guitar, kick drum,
and piano low register. The 80L cabinet is compatible with standard
professional 15" two-way formats at approximately 600×560×300mm
external. Round port velocity of 14.5m/s is within both PA and
install limits; slot port velocity of 5.7m/s is appropriate for
audiophile-grade installation environments. The 298mm slot port
can be located as a structural rear-panel element in cabinetry
with internal widths of 300mm or greater. The lower Le=0.55mH
of the -333 versus the -115 variant ensures reduced inductance
modulation distortion across the 50Hz–1kHz operating band at
high displacement, maintaining lower THD under demanding programme.
ALIGNMENT C — EXTENDED LF (110 L net internal)
Box volume: 110 L (net internal)
Tuning freq (Fb): 43 Hz
Round port: 100mm dia × 115mm long
Port velocity: 12.4 m/s (peak, at Xmax)
Slot port: 250×80mm × 293mm long
Port velocity: 4.9 m/s (peak, at Xmax)
System f-3dB: ~41 Hz
HP filter: 33 Hz, 24 dB/oct DSP (mandatory)
Max SPL (800W, 1m): ~125 dB
Application: Extended bass two-way cabinet, cinema main LF section,
installed music system where sub-bass is required from
the main loudspeaker, outdoor festival main speaker.
Notes: The deepest alignment. At 41Hz -3dB the system reaches the bass
guitar open E (41Hz) and low kick drum fundamentals with full
acoustic output — unusual capability for a standalone 15" two-way
PA cabinet. The 110L enclosure at approximately 650×600×350mm
external is the practical upper limit for a flyable two-way format;
non-flyable fixed-install versions may extend to this volume more
readily. Internal bracing is required to control panel resonances
at this volume. Port length is the shortest of the three alignments
(115mm round, 293mm slot) — a consequence of the larger box volume
more than compensating for the lower Fb. Slot port velocity of
4.9m/s produces negligible turbulence noise at all drive levels,
making this alignment suitable for theatre and cinema environments
where port noise must be completely inaudible. The 33Hz HP filter
must be robust — at and below 33Hz, cone excursion increases rapidly
as the enclosure unloads, and the -333's Xprot of 20mm, while
generous, must not be challenged without adequate DSP protection.
SYSTEM SUMMARY TABLE
| Alignment | Volume | Fb | f-3dB | Round Port | Slot Port | HP |
|-------------|---------|-------|-------|-------------------|-------------------|--------|
| A Compact | 50 L | 60 Hz | ~58Hz | 100mm × 130mm | — (impractical) | 45 Hz |
| | | | | v=17.4 m/s | | |
| B Standard | 80 L | 50 Hz | ~48Hz | 100mm × 117mm | 250×80mm × 298mm | 38 Hz |
| | | | | v=14.5 m/s | v=5.7 m/s | |
| C Extended | 110 L | 43 Hz | ~41Hz | 100mm × 115mm | 250×80mm × 293mm | 33 Hz |
| | | | | v=12.4 m/s | v=4.9 m/s | |
Sensitivity: 95.62 dB (1W/1m)
Max SPL (800W): ~125 dB at 1m
Impedance: 8 ohm nominal (Re=4.6Ω)
Voice coil: 76mm (3"), CCAW, Polyimide former (280°C rated)
Surround: NBR rubber — REDCATT proprietary high-excursion compound
Le: 0.55mH (low inductance — reduced HF phase shift vs -115)
Frequently Asked Questions
- - EXTENDED LOW FREQUENCY RESPONSE
- - Carbon fiber reinforced cone
- - High excursion rubber surround
ENCLOSURE RECOMMENDATIONS: 152FINDX8-333 Driver: 152FINDX8-333 (152FIND-333) — 15" ferrite pro mid-bass woofer, 8 ohm Key T/S: Fs=37Hz, Qts=0.44, Qes=0.46, Qms=10.2, Vas=119L, Sens=95.62dB Power: AES 800W / Cont 1600W / Peak 3200W Xmax=4.5mm (linear), Xmech=14.5mm, Xprot=20mm Sd=804cm², Bl=18.4T·m, Le=0.55mH, Re=4.6Ω Voice coil: 76mm (3"), CCAW winding, Polyimide former (280°C rated) Cone: carbon fiber loaded paper, environmentally treated Surround: NBR rubber (high-excursion compound, REDCATT formulation) Spider: Nomex Depth: 143mm | Baffle cutout: 360mm | Ferrite motor COMPARISON NOTE — 152FIND-333 vs 152FIND-115: The -333 variant shares the 15" platform and 76mm voice coil with the -115 (see 152FINDX8-115_enclosure_output.txt) but is tuned significantly differently. The -333 carries a heavier moving mass (Mms=140g vs 95.6g), producing a lower Fs of 37Hz (vs 44Hz) and a reduced sensitivity of 95.62dB (vs 99.03dB) — a deliberate trade-off favouring extended low- frequency reach and high-excursion control over raw efficiency. The NBR rubber surround replaces the fabric triple-roll, providing superior resistance to fatigue, UV exposure, and ozone at large cone displacements. Lower voice coil inductance (Le=0.55mH vs 0.98mH) reduces high-frequency phase shift and inductance modulation distortion, broadening the usable upper bandwidth. The -333 is the preferred choice when low-frequency extension, high displacement control under sustained drive, and outd...
The 152FINDX8-333 is a 15-inch professional mid-bass woofer designed for high-SPL two-way PA enclosures, fixed installation systems, and outdoor applications requiring extended low-frequency performance and high mechanical durability. The driver uses a 76 mm (3-inch) CCAW voice coil wound on a Polyimide former rated to 280°C, delivering 800 W AES and 1600 W continuous power handling at 8 ohms. With a Ferrite motor producing a Bl of 18.4 T·m and a deliberately elevated moving mass of 140 g, the -333 is tuned to a lower resonant frequency of 37 Hz compared to other drivers in the 152FIND platform — a design choice that prioritizes bass extension and displacement control over peak sensitivity. The result is a measured sensitivity of 95.62 dB (1 W/1 m), 3.4 dB below the higher-sensitivity -115 variant, with the trade-off being usable -3 dB output approximately 17 Hz lower. The voice coil inductance of Le=0.55 mH is significantly lower than competing 15-inch PA woofers of similar power class, reducing high-frequency inductance modulation distortion and preserving upper midrange clarity across the 50 Hz–1 kHz operating band at high displacement. The NBR rubber surround, produced from a REDCATT proprietary rubber compound, provides superior fatigue resistance, UV stability, ozone resistance, and compliance consistency compared to fabric surrounds under sustained high-excursion programme conditions, making the -333 the preferred choice for permanently installed outdoor systems and touring applications requiring extended service intervals.
The 152FINDX8-333 is optimized for vented (bass reflex) enclosures across a 50 to 110 litre net internal volume range, with tuning frequencies from 43 to 60 Hz. The compact 50 L alignment, tuned to 60 Hz, delivers -3 dB at approximately 58 Hz for high-output touring PA cabinets and column-format woofer sections; a 100 mm round port tube of 130 mm length is used, as the cabinet depth at this volume is insufficient for the slot port lengths generated by this tuning. The recommended 80 L standard alignment, tuned to 50 Hz, extends the -3 dB point to approximately 48 Hz, covering the full bass and lower midrange programme range from a standard professional two-way cabinet format; both a 100 mm round port (117 mm long, 14.5 m/s) and a 250×80 mm slot port (298 mm long, 5.7 m/s) are practical at this volume. The extended 110 L alignment at 43 Hz tuning achieves -3 dB at approximately 41 Hz — at the bass guitar open E fundamental — from a single 15-inch two-way enclosure, with slot port velocity of 4.9 m/s effectively eliminating turbulence noise across all drive levels. Port tube lengths decrease counter-intuitively as box volume increases across all three alignments (130 → 117 → 115 mm round), a product of the larger Vb more than compensating for the lower Fb, making port fabrication straightforward across the range.
The 152FINDX8-333 requires high-power professional amplification of 800–1600 W into 8 ohms, with DSP management mandatory including a 24 dB/octave high-pass filter at 45, 38, or 33 Hz depending on alignment. Below the tuning frequency, enclosure acoustic loading is removed and cone excursion rises rapidly; the Xprot of 20 mm provides a generous mechanical safety margin, but displacement-limiting in DSP is still essential at full programme power. The recommended operating bandwidth extends from approximately 40 Hz to 1.0–1.5 kHz; a 24 dB/octave low-pass crossover to a compression driver or high-frequency section at this frequency is standard for two-way system integration.
The 152FINDX8-333 is suited for: two-way touring PA enclosures requiring extended low-frequency performance and high mechanical durability from a 15-inch driver; permanently installed outdoor main speakers for amphitheatres, sports venues, festival sites, and theme parks where NBR rubber surround longevity is a primary service-life consideration; installed main speakers for theatres, houses of worship, and stadia where sub-bass coverage from the main enclosure is desirable; high-SPL club and venue systems operating at continuous programme levels with sustained high displacement; and cinema LF sections requiring bass guitar and low-drum fundamental reproduction without a supplementary subwoofer. Its combination of Fs=37 Hz, Le=0.55 mH, NBR rubber surround, and Polyimide former makes the -333 the acoustically deeper, mechanically more durable, and environmentally more robust variant within the 152FIND product platform.
AES Power: 800 W,
Continuous: 1600 W,
Peak: 3200 W.
Sensitivity: 95.62 dB (1W/1m).
