SKU: 91628827508

Sundown Audio - U-Series v.1 6.5"

Sale price$135.00 Regular price$150.00
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Ships within 48 hours · Estimated delivery Aug 21 - Aug 26

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Description

Sundown Audio - U-Series v.1 6.5"500 Watts RMS 1000 Watts Peak Dual 2 or 4 ohm voice coils Optimized for small ported enclosures Aluminum 1. 75 voice coil former for superior heat dissipation High temperature copper voice coil Double stitched surround Heavy duty cast basket Spring loaded terminals accept up to 8 gauge wire Stitched on heavy duty tinsel leads Solid pole with vent channels and aluminum shorting ring cap Rear gap venting Top Plate Cooling Channels Perfect for high power

  • 500 Watts RMS/1000 Watts Peak
  • Dual 2 or 4 ohm voice coils
  • Optimized for small ported enclosures
  • Aluminum 1.75” voice coil former for superior heat dissipation
  • High-temperature copper voice coil
  • Double stitched surround
  • Heavy-duty cast basket
  • Spring-loaded terminals accept up to 8-gauge wire
  • Stitched-on heavy-duty tinsel leads
  • Solid pole with vent channels and aluminum shorting ring cap
  • Rear gap-venting
  • Top-Plate Cooling Channels

Perfect for high-power underseat enclosures and designed to be at home in the competition lanes or playing your favorite tunes, the U Series is the premier “standard suspension” woofer in the Sundown lineup. A double-stacked 9” wide ferrite magnet system is coupled to a thick top plate. A thick set of shorting rings are also used inside the magnets and on the pole cap, smoothing out frequency response while doubling as a heat sink and airflow guide. An all-new, substantially thicker custom aluminum frame was designed specifically for the U Series, and equipped with heat-dissipation ribs. The v.2 motor also features an extended pole piece to keep the coil controlled under high stress!

Specifications

RE (Ohms) 4.0586 6.6274
FS (Hz) 41.9533 38.6925
VAS (L) 2.9053 3.7701
Qes 0.5238 0.5005
Qms 8.5834 7.2470
Qts 0.4937 0.4681
Le (mH) 4.0112 5.5892
BL (NA) 16.7428 20.0082
Mms (Grams) 137.2546 124.3518
Cms (uM/N) 104.8528 136.0613
Sens (dB @ 1w/1m) 77.8706 78.1460
Xmax 19mm 19mm
T/S SPECS U-6.5SW" D2 U-6.5SW" D4
   

Enclosure Specifications

  • Ported Enclosure
    • Size: .25-.35 cu. ft. net
    • Port Area: 4-5 sq. in.
    • Port Tuning: 35hz -40hz
  • Sealed Enclosure
    • Size: 0.125-0.2 cu. ft. net
    • Displacement:  .04 cu. ft. 
  • Depth:  5.71"
  • Outside Diameter: 7.17"
  • Cutout: 5.94"

Physical Dimensions

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 91628827508

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4.6 ★★★★★
Based on 29 reviews
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Product Reviews
M
Verified Purchase
Mama-Corvi
Lexington, US
★★★★★ 5
Fat tire savior
Size: 1 Gallon + Tool, Set name: Off-Road Formula
The best fat tire and dirtbike sealant we have found and love the gallon size. Pump clogs but clears with a strong push and love that it is water cleanup.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 16, 2026
J
Verified Purchase
JRTX
Belleville, US
★★★★★ 5
Worked perfectly for me. Sorry I waited so long.
Size: 1 Gallon + Tool, Set name: Off-Road Formula
I was clearing a field full of mesquite trees, and my tractor tires were getting destroyed. Mesquite has nasty 3-inch thorns, and I was plugging tires constantly. Eventually, all four tires were flat at the start of each day. These tires had been plugged more than 10 times each. I bought FlatOut Quick Strike and followed the instructions exactly. The pump dispenses about 1 oz per pump, so I put 30 pumps in each tire, and the bottle was mostly empty by the time I finished. Typical with any pump dispenser it was also difficult to get the last bit out of the bottle using the pump. It’s been a week now. One tire has lost about 1 PSI, but the other three are still holding exactly where I set them. Considering how badly these tires were damaged, I’m impressed so far. This is the first time I’ve gone more than a day without dealing with flats in that field.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 13, 2026
D
Verified Purchase
Duncan Souza
Louisville, US
★★★★★ 4
Pump is worthless
Size: 1 Gallon + Tool, Set name: Small Tire/Bicycle Formula
The sealant is good. The gallon pump is a joke. Pump stopped working 4 pumps in. Went and got another replacement pump from automotive store, also broke after 4 pumps. Ended up cleaning out an old Slime bottle and pouring in the flat out sealant in the slime bottle, so I could actually get it in my tires.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 30, 2026
A
Verified Purchase
Amazon Customer
Boise, US
★★★★★ 1
There seems to be a chronic problem with the provided dispensing pump.
Size: 1 Gallon + Tool, Set name: Off-Road Formula
I looked at online reviews of the product performance and was impressed by its purported ability seal tire punctures. While the product may (or may not) perform well, the provided dispensing pump is pathetically unsuited for the application and it is impossible to clear the pump once the material clogs the small dispensing port. Some of the reviews indicated this but i assumed that they were not very mechanical inclined customers. The product, by design, has particulates, of varying sizes, suspended in the liquid sealant. The port on pump is very small and easily becomes blocked with the sealant and particulates that cannot be cleared; even when following the instructions to do so. It is very irresponsible for the manufacturer to continue selling this item with inevitable relative failure of the pump as this is the only way to get the sealant into a tire.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 2, 2025
V
Verified Purchase
VT
Port Orchard, US
★★★★★ 5
Good for ebike tires
Size: 1 Gallon + Tool, Set name: Small Tire/Bicycle Formula
Got it for my son’s older ebike that my wife rides now. He kept on popping tubes, maybe because of his weight. Anyhow, I fixed it up for my wife and put some FlatOut in it to prevent flats. Seems to work so far. Got the off road FlatOut for my ebike’s fat tires. Easy to add to the tires. The pump clogs up but it’s easy to clean. I will always add this to all tires moving forward!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 4, 2026

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