The SD-4 series is our premier sealed box offering & is the successor to the SD-3. We started off this design knowing that the majority of sealed box applications today face a depth restriction so each SD-4 model was designed to have the lowest depth possible while still maintaining a large window of mechanical cushion (about 2” p-p maximum mechanical travel for all models). We do not consider the SD-4 an “ultra-shallow” but they are as shallow as possible and feature several techniques to reduce the effective depth required.
As mentioned above; the SD-4 series effectively requires less depth than other woofers that are more physically shallow. First of all they lack a pole vent, thus, require no room for air venting behind the motor. This allows the motor to be completely flush against the back wall of the enclosure. To allow for efficient air-cooling we added vent channels on the OD of the pole and side-firing gap venting. Secondly the entire SD-4 series features an all-new foam “W” shape surround – this reduces the space required in front of the woofer gasket to about 1” total. So, despite not being an “ultra-shallow” woofer they have an effective total depth requirement of about 2” less than most traditional woofers of an equal depth. The fourth generation series also upgrades to NEO motors to reduce angled depth requirements substantially versus the SD-3 series!
The SD-4 series truly is a world-class sound quality woofer with low mounting depth, small box requirements, and a reasonable price. This line features an under-hung motor topology – this means that the voice coil is shorter than the top plate so the amount of winding in the gap doesn’t change at all over the center portion of stroke – in this case featuring a 1” thick top plate and ½” long 8-layer copper voice coil. This allows for 14.5mm linear excursion one-way while maintaining an extremely flat BL curve. The all new “W” surround design and newly tooled spider work together to create a flat “center” compliance curve which quickly turns progressively stiffer past the linear limits of the motor. This was heavily optimized in 3D computer simulations. This makes the SD-4 significantly more mechanically rugged than the previous generation. To top off distortion reduction features the SD-4 features a shorting ring around the bottom of the pole-piece to even out the LE curve.
We borrowed some technology from our large high-excursion woofers and incorporated a hyper-extended pole-piece into the SD-4 line. This helps to prevent voice coil rocking & related damages at higher levels of stroke, especially past linearity of the motor. Thanks to our extensive experience in building high-stroke subwoofers we were able to ruggedize a shallow platform as well.
The parameter set has been optimized for very small sealed enclosures for this line. As opposed to the outgoing SD-3 series the 4th generation will tolerate a ported box when necessary.
• Xmax = 14.5mm one-way by 70% BL
• RMS Power = 600-watts (400-watts for the 8” model)
• Under-Hung low distortion motor topology
• Solid pole piece with chamfered edges
• Black Aluminum 2.5” voice coil former for superior heat dissipation (2” for 8” model)
• High Temperature 8-Layer copper voice coil wire
• Large aluminum faraday ring (Pole Base OD)
• Spring Loaded Terminals
• Stitched-On Tinsel Lead Wires
• Optimized for small sealed enclosures
• Computer Optimized Foam “W” Surround
• High strength cast aluminum frames (8” model features US Patent D691595)
|Sens (dB @ 1w/1m)||82.93||82.77|
|Sealed Enclosure||0.5-0.75 cu ft|
|Ported Enclosure||Not Recommended|
Other DetailsYour new Sundown Audio subwoofer is covered by a 2 year limited warranty if purchased from Car Audio Bargain. This warranty does not cover improper installation, accidental damage, misuse, abuse, improper wiring, operation of unit outside of listed specifications, or any product that has been modified or repaired by anyone other than Sundown Audio. This warranty does not cover burnt voice coils or other damage from to much power - re-cones for most products are available for sale in these cases. Warranty on subwoofers and loudspeakers is NOT transferrable. All warranty returns must be sent freight prepaid to Sundown Audio and be accompanied by the original sales invoice or receipt. For faster warranty service please contact Sundown Audio to request a return authorization code. At the sole discretion of Sundown Audio your subwoofer will be either repaired or replaced. If no defect is found and the unit must be shipped back the customer is responsible for return freight, if the unit is truly defective the replaced or repaired unit will be shipped back prepaid. In the event of shipping damage due to improper packaging of the return the customer is liable for the cost of all damages, necessary repairs, or replacement. Be sure to properly pack your return! Sundown Audio also offers a 5 year guarantee to our customers for a discounted replacement unit. We are so certain of the quality of our equipment that even if you are at fault for causing damage to your subwoofer Sundown Audio will offer you a new unit at a reduced cost compared to MSRP. Contact us via e-mail to take advantage of this offer. As is the case with standard warranty claims the return MUST be sent prepaid and with a copy of the original invoice or receipt. In no event will Car Audio Bargain be liable for incidental, consequential, or other damages resulting from the use of this product, this includes but is not limited to, damage of hearing, property or person, damage based upon inconvenience or on loss of use of the product, and to the extent permitted by law, damages for personal injury. This warranty gives you specific legal rights, and you may have other rights, which vary from state to state. This warranty applies to products sold and used in the United States of America.
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