Sundown Pair of 12" U-Series D4 Subs, Marts Digital Amp w/ Dual Vented Enclosure

• Expertly paired subwoofers, enclosure, and amplifier for optimal performance and synergy.
• Due to the nature of the items in this package, each item will be shipped individually.
• GP/Tru-Spec Enclosures assembled in the USA.
• Includes a FREE 2-Year Extended Accidental & Repair Warranty card that covers all electronics in this package.

Sundown Pair of 12" U-Series D4 Subs, Marts Digital Amp w/ Dual Vented Enclosure

This Listing Includes:

• (1) Dual 12" Vented Subwoofer Enclosure


• (2)  12" U-Series Sundown Subwoofers


• (1) Marts Digital MP-3500-1-V2 Amplifier


• (1) CPS Extended Accidental & Repair Warranty Card

Subwoofer Features:

• Black Aluminum 3" voice coil former for superior heat dissipation


• High Temperature Round-Wire ALU voice coil with high-temp black adhesive


• Double stitched surround


• Heavy duty cast baskets - all new, custom-tooled


• Spring loaded terminals accept up to 8 gauge


• Stitched-on double-XL tinsel leads


• Solid pole with vent channels and aluminum shorting ring cap


• Rear drilled gap-venting


• Innovative high-velocity cast aluminum vented frame spacer ring


• Magnet ID shorting ring


• Top-Plate Cooling Channels


• Cast Aluminum surround bolt-on rings


• Optimized for small ported or bandpass enclosures

Subwoofer Specifications U12 D4:

• RE (Ohms): 6.0577


• FS (Hz): 41.9087


• VAS (L): 14.7535


• Qes: 0.5870


• Qms: 4.9022


• Qts: 0.5242


• Le (mH): 4.3694


• BL (NA): 31.1265


• Mms (Grams): 356.5462


• Cms (uM/N): 40.4498


• Sens (dB @ 1w/1m): 84.4191

Amplifier Features

• High-performance Class D amplifier


• Immersive audio experience


• Powerful 3500 Watts output at 1 Ohm


• Compact and sleek design


• Secure seat for an electrifying sonic journey

Amplifier Technical Specifications:

• RMS Power at 1 Ohm: 1CH x 3600W


• RMS Power at 2 Ohm: 1CH x 2520W


• RMS Power at 4 Ohm: 1CH x 1500W


• Total Harmonic Distortion (THD): 0.25%


• Low Pass Filter (LPF): 80Hz-20kHz


• Subsonic Filter: 10Hz - 60Hz


• Frequency Response: 10Hz - 20kHz


• Signal-to-Noise Ratio (S/N): 83dB

Amplifier Dimensions:

• LxWxH: 10.5 x 11.5 x 3 inches


• Weigt: 9.56 lbs

Enclosure Specifications:

• Material Thickness: 0.75"


• Net Internal Volume: 3.50 ft3


• Tuning Frequency: 35 Hz


• Port Area: 52.00 inch2


• Cutout Diameter: 11.20"


• Flush Trim Diameter: 13.10"

Enclosure External Dimensions:

• Length: 34.00"


• Depth: 14.00"


• Height: 22.00"

Accepted Payment Methods at Big Jeff Audio

At Big Jeff Audio, we strive to make your shopping experience as smooth as possible by offering a wide variety of payment options. Below is a complete list of the payment methods we accept:

Credit and Debit Cards

• Visa
• Mastercard
• American Express
• Discover
• Diners Club

Digital Wallets

• Amazon Pay
• Apple Pay
• Meta Pay (formerly Facebook Pay)
• Google Pay
• Shop Pay
• PayPal

International Payment Methods

• Bancontact
• iDEAL

Bank Transfers

• Zelle

Financing Options

We also offer financing options to make purchasing easier. Learn more about our financing options here.

• Klarna
• Affirm
• Sezzle
• Snap
• Acima
• Tiptop

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.

Shipping Options and Delivery Time

Do You Offer Expedited Shipping?

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

• Standard Shipping: Free for orders over $100.
• Expedited Shipping: Available at an additional cost, calculated based on the weight and destination of your order.

How Long Does Delivery Take?

• 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.
• Standard Shipping: Typically takes 3-5 business days, though delivery may be affected by extreme weather or holidays.

What Happens If My Package Is Undeliverable?

If your package is refused or marked undeliverable and returned to us by the carrier, you’ll need to pay the full shipping cost to have the package resent. Alternatively, we can refund your order, minus the cost of shipping.

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• Make sure you’ve received the shipping confirmation email with the tracking number.
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• If the issue persists, please refer to our detailed guide on tracking your order or contact our customer service team for further assistance.