61XR

Name: 61XR
Brand: REDCATT
SKU: 61XRX4-404D

Design Notes

The 61XR was designed to be simply the best driver for 2-way and multi-way systems on the market. We bring this with clarity in the mid-frequencies and undistorted bass. The combination of our XR patented technology with static shorting coil brings an nonparallel opportunity to the audio designers.
Motor Design
The magnetic design incorporates large neodymium magnets placed along the voice coil winding, together with the 2nd and static coil placed on the pole piece. This has allowed us to push the cone excursion to 30mm peak to peak, while lowering the inductance. The shorting coil covers the complete main coil excursion. This is also an improvement compared to some previous designs on the market.
Our extensive R&D on the surround foam material has yielded material that has proven its benefits over and over again. The surround is extremely light, yet it allows the cone excursion as the traditional, but heavier, rubber surround.
61XR best application is in hi-quality home hi-fi applications and studio monitors where the requirements for precise sound reproduction without distortion artifacts are required.

Specifications

General Specs

Nominal Diameter 6"

Rated Impedance 4 Ohm

Magnet Neodymium

Basket Material Aluminum

Power Handling

AES Power 100 W

Continuous Power 200 W

Peak Power 400 W

Voice Coil

Diameter 44.5 mm

Winding Wire Copper

Former Glass Fiber

Winding Height 10.3 mm

T/S Parameters

Resonant Frequency (Fs) 64.00 Hz

Re 3.10 \u2126

Qes 0.960

Qms 2.88

Qts 0.720

Vas 8.60 liters

Sd 132.70 cm\u00B2

Mms 17.30 grams

Rms 2.40

Cms 0.3600

Bl 4.77 T\u00B7m

Le 0.060 mH

Sensitivity 87.02 dB

Design Details

Surround Material Foam

Cone/Dome Material Paper CF

Spider Nomex

T-Plate 26.5 mm

Xmax (peak) 8.1 mm

Xmech 16.6 mm

Overall Diameter 181.50 mm

Bolt Circle Diameter 169.50 mm

Baffle Cutout Dia. 151.00 mm

Mounting Holes 6

Depth (flange to rear) 94.00 mm

Net Weight 1.50 kg

Ordering Codes

Product Code 61XRX4-404D

Downloads

2D Drawing (PDF) 3D Model (STEP)

Frequency Response & Impedance

2D Drawing

Technical Summary

The 61XRX4-404D is a 6-inch mid-woofer engineered for high-fidelity home audio and studio monitoring, built around the proprietary XR motor topology with radial neodymium magnets and both secondary and static shorting coils. The dual shorting coil design reduces voice coil inductance to just 0.06 mH, virtually eliminating inductive impedance rise and enabling extended, distortion-free midrange performance well suited for precise crossover integration.
In sealed enclosures of 8 to 20 liters, the driver delivers controlled bass response with -3 dB points between 65 and 71 Hz depending on cabinet volume. The high Qts (0.72) produces a slightly warm sealed response that pairs naturally with room gain in domestic listening environments. Vented enclosures are not recommended for this driver due to impractical port dimensions at the required small box volumes.
The driver handles 100 W AES (200 W continuous) into its 4-ohm nominal impedance, with exceptional mechanical headroom — 8.1 mm Xmax and 16.6 mm Xmech (30 mm peak-to-peak) — enabling sustained low-frequency output well below the sealed resonance. This excursion capability, unusual for a 6-inch frame, makes the driver effective in both standalone 2-way designs and in active systems with subwoofer support.
Intended applications include premium bookshelf and standmount loudspeakers, nearfield and midfield studio monitors, and mid-woofer duty in multi-way floorstanding systems where clarity, low distortion, and precise imaging are paramount.

Enclosure Recommendations

ENCLOSURE RECOMMENDATIONS: 61XRX4-404D
Driver: 61XRX4-404D (61XR) — 6" mid-woofer
Key T/S: Fs=64.0Hz, Qts=0.72, Vas=8.6L, Sens=87.02dB
Power: AES 100W / Cont 200W / Peak 400W
Xmax=8.1mm, Xmech=16.6mm, Sd=132.7cm², Bl=4.77T·m
Le=0.06mH (ultra-low inductance — static shorting coil)
RECOMMENDED ENCLOSURE TYPE: Sealed (Acoustic Suspension)
DESIGN HIGHLIGHTS:
  - XR (eXtended Range) patented motor topology with radial neodymium
    magnets placed along the voice coil winding
  - Secondary AND static shorting coil on pole piece — reduces inductance
    to 0.06mH, virtually eliminating inductive rise across the audio band
  - Exceptional excursion: 8.1mm Xmax / 16.6mm Xmech (30mm peak-to-peak)
    in a 6" frame — compensates for sealed rolloff with sustained output
    well below resonance
  - Ultra-light foam surround enables full excursion without the mass
    penalty of traditional rubber surrounds
NOTES ON ENCLOSURE CHOICE:
The high Qts (0.72) combined with the small Vas (8.6L) makes this driver
ideally suited for sealed enclosures in the 8–20 liter range. Vented
enclosures are impractical: even with a modest 50mm port, the small box
volumes required produce port lengths exceeding 350mm, and port velocities
above 20 m/s — resulting in turbulence and chuffing. The sealed topology
also aligns with the driver's intended hi-fi and studio monitor
applications, where superior transient response, predictable phase
behavior, and clean 12dB/oct rolloff are preferred.
  a) Compact Studio
     Net Volume: 8 liters
     Qtc: 1.04
     fc: 92 Hz
     Est. -3dB: 71 Hz
     Notes: Tight, punchy response with ~1dB mid-bass emphasis around
            90 Hz. Ideal for compact nearfield studio monitors where a
            subwoofer handles content below 60–70 Hz. Small cabinet
            minimizes baffle diffraction for improved imaging.
  b) Balanced Hi-Fi
     Net Volume: 15 liters
     Qtc: 0.90
     fc: 80 Hz
     Est. -3dB: 66 Hz
     Notes: Slightly warm tonal balance with good transient control.
            Well-suited for standalone 2-way bookshelf speakers in
            small to medium rooms. Natural bass rolloff integrates
            easily with room gain.
  c) Extended Hi-Fi
     Net Volume: 20 liters
     Qtc: 0.86
     fc: 77 Hz
     Est. -3dB: 65 Hz
     Notes: Flattest in-band response and best group delay performance.
            Recommended for critical listening and reference monitoring
            where the speaker is the primary LF source. Larger cabinet
            suits floorstanding designs or larger standmount enclosures.
CROSSOVER AND SYSTEM INTEGRATION:
  - The ultra-low Le (0.06mH) maintains flat impedance through the
    crossover region, greatly simplifying passive crossover design and
    improving compatibility with active DSP crossovers
  - Typical crossover to tweeter: 2.0–3.5 kHz (the extended cone
    geometry supports response well into the midrange)
  - For 2-way systems: 24dB/oct Linkwitz-Riley at 2.5–3.0 kHz
    recommended to protect the tweeter while leveraging the driver's
    clean midrange
  - Sub integration: high-pass at 60–80 Hz (sealed rolloff provides
    natural LR2 alignment with many subwoofer crossover topologies)
AMPLIFICATION NOTES:
  - Nominal impedance is 4 ohm (Re=3.1Ω), so amplifier must be rated
    for 4-ohm operation
  - Recommended amplifier power: 50–200W into 4 ohm
  - The extreme excursion capability (16.6mm Xmech) provides significant
    mechanical headroom, but thermal limits (100W AES) should be
    respected with appropriate limiters in active systems
  - In sealed enclosures, excursion increases at 12dB/oct below fc —
    the 8.1mm Xmax provides usable output to approximately 40 Hz in
    alignment (a), 35 Hz in alignment (c), before mechanical limiting
    is needed
APPLICATION NOTES:
  - Primary: Hi-fi 2-way bookshelf and standmount loudspeakers
  - Primary: Nearfield and midfield studio monitors
  - Secondary: 2.5-way or 3-way floorstanding systems (mid-woofer role)
  - Secondary: Active studio systems with DSP crossover and subwoofer
  - The weatherized foam surround and paper cone construction are
    suitable for controlled indoor environments (studio, living room)
  - 4-ohm impedance allows parallel wiring of two drivers per channel
    for 2-ohm capable amplifiers (D'Appolito MTM arrays)

Frequently Asked Questions

- EXTENDED FREQUENCY RESPONSE, incredible sound reproduction clarity
- Secondary AND STATIC shorting COIL
- High power handling

ENCLOSURE RECOMMENDATIONS: 61XRX4-404D
Driver: 61XRX4-404D (61XR) — 6" mid-woofer
Key T/S: Fs=64.0Hz, Qts=0.72, Vas=8.6L, Sens=87.02dB
Power: AES 100W / Cont 200W / Peak 400W
Xmax=8.1mm, Xmech=16.6mm, Sd=132.7cm², Bl=4.77T·m
Le=0.06mH (ultra-low inductance — static shorting coil)
RECOMMENDED ENCLOSURE TYPE: Sealed (Acoustic Suspension)
DESIGN HIGHLIGHTS:
  - XR (eXtended Range) patented motor topology with radial neodymium
    magnets placed along the voice coil winding
  - Secondary AND static shorting coil on pole piece — reduces inductance
    to 0.06mH, virtually eliminating inductive rise across the audio band
  - Exceptional excursion: 8.1mm Xmax / 16.6mm Xmech (30mm peak-to-peak)
    in a 6" frame — compensates for sealed rolloff with sustained output
    well below resonance
  - Ultra-light foam surround enables full excursion without the mass
    penalty of traditional rubber surrounds
NOTES ON ENCLOSURE CHOICE:
The high Qts (0.72) combined with the small Vas (8.6L) makes this driver
ideally suited for sealed enclosures in the 8–20 liter range. Vented
enclosures are impractical: even with a modest 50mm port, the small box
volumes required produce port lengths exceeding 350mm, and port velocities
above 20 m/s — resulting in turbulence and chuffing. The sealed topology
also aligns with the driver's intended hi-fi and studio monitor
applications, where superior transient response, predictable phase
behavior, and clean 12dB/oct rolloff are preferred.
  a) Compact Studio...

The 61XRX4-404D is a 6-inch mid-woofer engineered for high-fidelity home audio and studio monitoring, built around the proprietary XR motor topology with radial neodymium magnets and both secondary and static shorting coils. The dual shorting coil design reduces voice coil inductance to just 0.06 mH, virtually eliminating inductive impedance rise and enabling extended, distortion-free midrange performance well suited for precise crossover integration. In sealed enclosures of 8 to 20 liters, the driver delivers controlled bass response with -3 dB points between 65 and 71 Hz depending on cabinet volume. The high Qts (0.72) produces a slightly warm sealed response that pairs naturally with room gain in domestic listening environments. Vented enclosures are not recommended for this driver due to impractical port dimensions at the required small box volumes. The driver handles 100 W AES (200 W continuous) into its 4-ohm nominal impedance, with exceptional mechanical headroom — 8.1 mm Xmax and 16.6 mm Xmech (30 mm peak-to-peak) — enabling sustained low-frequency output well below the sealed resonance. This excursion capability, unusual for a 6-inch frame, makes the driver effective in both standalone 2-way designs and in active systems with subwoofer support. Intended applications include premium bookshelf and standmount loudspeakers, nearfield and midfield studio monitors, and mid-woofer duty in multi-way floorstanding systems where clarity, low distortion, and precise imaging are paramount.

AES Power: 100 W, Continuous: 200 W, Peak: 400 W. Sensitivity: 87.02 dB (1W/1m).

Key Features

Quick Specs