B2 Audio 3 Way 6.5" REF SQ Series Component Passive Crossover OPEN BOX

• Some scratches, grills a little bent, drop of glue on surround, gold bottom scratched, one tweeter has a small dent on diaphragm
• Multi-Layer Carbon Fiber Cones – Both midrange and midbass drivers use rigid, lightweight carbon fiber construction for clean, controlled performance and powerful output with minimal distortion.
• 1" Ceramic Dome Tweeters – Delivers incredibly accurate and delicate high-frequency detail with a CCAW voice coil, dual neodymium magnets, and vented aluminum housing for low distortion and heat control.
• 3" Full-Range Mids with CNC Gold Detailing – FEA-optimized neodymium motor with precisely fitted copper cap and gold-plated CNC yoke and top plate ensures low compression, rich vocals, and smooth upper mids.
• High Efficiency and Low Compression Design – Vented die-cast aluminum baskets, copper shorting rings, and non-conductive voice coil formers maximize airflow, thermal dissipation, and clarity at high volumes.
• Power Ratings – 6.5" Midbass: 100W Max / 70W RMS | 3" Full-Range: 100W Max / 30W RMS | 1" Tweeter: 75W Max / 25W RMS | Nominal Impedance: 4Ω (Woofer & Mid), 3Ω (Tweeter).

B2 Audio 3 Way 6.5" REF SQ Series Component Passive Crossover OPEN BOX

This is an open-box item in perfect working condition. 

The product has been previously mounted, so you will see light cosmetic wear. The retail box has been opened and may show handling marks.

Our technician inspected the full set and noted the following cosmetic details. None of these issues affect performance.

The 1 inch tweeter has a bent grill. The tweeter diaphragm has a small dent, although it’s barely visible once the grill is in place. Both tweeters show minor scratches on the mounting rings, and one has a small scratch beneath the grill.

The 3 inch speakers have slightly bent grills.

The 6.5 inch speakers show scratches on the bottom of the baskets, and one of them has a small drop of clear adhesive on the surround.

This open-box product is sold As Is. Open-box items are not eligible for returns, and any return requests will be declined.

This Listing Includes:

• (2) 6.5" Carbon Fiber Cone Mid-woofers


• (2) 3" Carbon Fiber Full-Range Midrange Speakers


• (2) 1" Ceramic Dome Tweeters


• (2) Passive 2-Way Crossovers

Item Description

Experience breathtaking clarity and full-spectrum precision with the B2 Audio REFSQ63 Reference Series 3-Way Component Set, a world-class sound solution crafted for competition-level sound quality and elite daily setups.

This system blends powerful, musical 6.5" mid-woofers with ultra-clear 3" mids and ultra-responsive 1" ceramic dome tweeters. Every element has been engineered for maximum resolution, low distortion, and linear dynamics, letting your audio system reproduce every nuance with richness and accuracy.

From the deep control of the midbass to the articulate full-range vocals and the shimmering finesse of the highs, the REFSQ63 delivers a coherent and immersive soundstage worthy of the Reference badge.

Features

• 6.5" & 3" multi-layer carbon fiber cones for strength, control, and musicality


• 1" ceramic dome tweeters for extremely accurate and delicate high frequencies


• FEA-optimized neodymium motors on tweeter and midrange


• Non-conductive TIL voice coil formers for damping control


• CCAW and copper voice coils for reduced moving mass


• Gold-plated top plates, CNC aluminum baskets and trim rings


• Vented baskets and pole pieces for thermal and acoustic efficiency


• Perfect for active or passive 3-way SQ builds

Crossover Configuration Explained:

This set includes a 2-way bi-amp crossover, designed to let you run the woofer and tweeter on separate dedicated amplifier channels. This setup is especially popular among SQ (sound quality) enthusiasts who want maximum control and refinement in their system.

While a true tri-amp crossover would require a 6-channel amplifier with identical circuits (adding complexity and cost), this crossover offers more flexibility. You can run it as a 2-way (woofer + tweeter per side), while the included 3" full-range driver can be crossed over actively with your DSP or amplifier.

This allows you to create a passive/active hybrid system using only a 4-channel amplifier, or go fully active with a DSP for ultimate control. The design gives you the freedom to choose between traditional passive convenience or advanced active configurations - all without being locked into one option.

Component Specifications:

6.5" Midwoofer:

• Max Power Handling: 100W


• RMS Power Handling: 70W


• Nominal Impedance: 4 Ohm


• Voice Coil Diameter: 1.4" / 35.5 mm


• Cone Material: Multi-layer Carbon Fiber


• Magnet: High Density Ferrite


• Frequency Response: 50 Hz - 10 kHz


• Sensitivity (1W/1M): 87.6 dB


• Mounting Depth: 2.93" / 74.5 mm


• Cutout Diameter: 5.31" / 135 mm


• Overall Diameter: 6.5" / 165 mm


• Unit Weight: 3.74 lbs / 1700g

3" Mid-Range:

• Max Power Handling: 100W


• RMS Power Handling: 30W


• Nominal Impedance: 4 Ohm


• DC Resistance: 3.35 Ohm


• Voice Coil Diameter: 1.2" / 30.5 mm


• Voice Coil Former: TIL (non-conductive)


• Voice Coil Wire: Copper


• Magnet: Neodymium, FEA-optimized with copper cap


• Cone Material: Multi-layer Carbon Fiber


• Basket: Vented Die-Cast Aluminum


• Frequency Response (-3dB): 200 Hz - 20,000 Hz


• Sensitivity (1W/1M): 88.0 dB


• Mounting Depth: 1.52" / 38.6 mm


• Cutout Diameter: 3.02" / 76.8 mm


• Overall Diameter: 3.62" / 92 mm


• Unit Weight: 450g

T/S Parameters:

• Fs: 131.8 Hz


• Qms: 5.575


• Qes: 0.379


• Qts: 0.355


• BL: 5.392 T-M


• Mms: 3.97 g


• Cms: 0.367 mm/N


• Vas: 0.475 L


• Sd: 30.19 cm


• Le: 0.151 mH


• Zo Max Impedance: 52.653 Ohm


• Zmin: 3.974 Ohm


• Reference Efficiency: 0.278%

1" Ceramic Dome Tweeter

• Max Power Handling: 75W Peak / 25W RMS


• Nominal Impedance: 3.0 Ohm


• DC Resistance: 2.3 Ohm


• Voice Coil Diameter: 1.0" / 25.4 mm


• Voice Coil Former: Polyimide


• Voice Coil Wire: CCAW


• Cooling: Vented + copper conduction


• Magnet Structure: Internal dual neodymium


• Dome Material: Ceramic


• Surround: VC-connected only - no dome interaction


• Housing: CNC Aluminum for low resonance and thermal control


• Frequency Response (-6dB): fs ~ 20,000 Hz


• Sensitivity (1W/1M): 86.0 dB


• Mounting Depth: 1.1" / 28 mm


• Cutout Diameter: 1.79" / 45.4 mm


• Overall Diameter: 2.24" / 57 mm


• Unit Weight: 150g

T/S Parameters:

• Fs: 553.9 Hz


• Qms: 3.359


• Qes: 0.893


• Qts: 0.705


• BL: 2.691 T-M


• Mms: 0.808 g


• Cms: 0.102 mm/N


• Vas: 9.386 mL


• Le: 0.040 mH


• Zo Max Impedance: 10.955 Ohm


• Zmin: 2.903 Ohm


• Reference Efficiency: 0.173%

Dimensions

• Shipping box size: 20.25" x 13.25" x 4.5"


• Shipping weight 14.10 lbs

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If you have any questions or need assistance with payments, feel free to reach out to us at info@bigjeffaudio.com or call us at 737-BIG-JEFF.

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Do You Offer Expedited Shipping?

Yes! At checkout, you can select from different shipping options:

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• Handling Time: Most orders are processed and shipped within 1 business day after receiving cleared payment. Occasionally, additional handling time may be required, but we’ll notify you if that’s the case.
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