About the Alpine SWR-1521D
Introduce yourself to Alpine's top-of-the-line 15" low frequency behemoth and understand what low frequency power really means. The SWR-1521D 15" dual 2-ohm voice coil Type-R sub is ready to throw loads of power back at you up to 1,500 watts peak while still reproducing your music with remarkable accuracy.
The motor structure and double-stacked magnets focus magnetic energy within the vented pole piece so you get incredible output levels. The pulp cone has been reinforced with Kevlar® (the material used in bulletproof vests) for extra rigidity, so it will stand up to hard play. A 1-1/4" Santoprene rubber surround helps to maximize cone travel for deep bass and resists decay that can mar speaker output. An extended spider landing area provides extra excursion for fuller sound.
The dual 2-ohm, 2-1/2" voice coils handle all that power and let you wire your system for high output or efficiency. The tinsel leads won't split apart they're woven into the dual progressive Nomex spiders. The tinsel lead design also helps you get nearly 3" of cone excursion for maximum output. An aluminum diecast frame provides a secure, non-resonant housing.
The SWR-1521D is designed for use in sealed or ported enclosures.
Note: If you are wiring this DVC sub for lower impedance, make sure that your amp is compatible. Most car amplifiers are stable down to 2 ohms in standard mode, or 4 ohms in bridged operation.Details:
- 15" subwoofer with dual 2-ohm voice coils
- Kevlar®-infused pulp cone with Santoprene rubber surround
- frequency response 22-1,000 Hz
- power range 200-500 watts RMS (250 watts RMS per coil)
- peak power handling 1,500 watts
- sensitivity 89 dB
- top-mount depth 8-3/4"
- sealed box volume: 1.3-2.5 cubic feet
- ported box volume: 1.5-3.0 cubic feet
- Recommended Q-Logic Box Type: 1
- 1-year warranty
Priced per speaker
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More details on the Alpine SWR-1521D
Features & specs
|Impedance||1 ohm or 4 ohms|
|Cone Material||Kevlar Reinforced Pulp|
|Surround Material||1-1/4" Santoprene Rubber|
|Ideal Sealed Box Volume (cubic feet)||1.5|
|Ideal Ported Box Volume (cubic feet)||2.25|
|Port diameter (inches)||4|
|Port length (inches)||10|
|Dual Voice Coil||Yes|
89 dB at 1 watt |
|Frequency Response||22 - 1000 Hz|
|Max RMS Power Handling||500|
|Peak Power Handling (Watts)||1500|
|Top Mount Depth (inches)||8 3/4|
|Bottom Mount Depth (inches)||9 11/16|
|Cutout Diameter or Length (inches)||13 3/4|
|Parts Warranty||1 year|
|Labor Warranty||1 year|
Kevlar Reinforced Pulp Cone: This Alpine Type-R subwoofer has a Kevlar reinforced pulp cone. Kevlar adds strength and tear resistance to the woofer cone while maintaining the benefits of a pulp cone design. There is also an oversized inverted dust cap of the same material, which increases rigidity and virtually eliminates distortion at extreme volume levels.
Santoprene Rubber Surround: The high-excursion 1-1/4" Santoprene rubber surround is durable and resistant to the elements, resulting in a very reliable performance. The surround is specially designed to resist deformation that is common in most woofers with wide surrounds. This design gives the surround more control over the woofer cone to reduce distortion and possible driver failure.
Dual Progressive Nomex Spiders: This subwoofer has dual progressive Nomex spiders for added stability and mechanical durability. The custom progressive rolls give the woofer a longer, more linear stroke with maximum centering and restoring force. Special edge control design and Nomex construction provide excellent tear resistance, strength and long-term reliability. By integrating the tinsel leads into the top spider, a nearly 3" peak-to-peak excursion can be achieved with a shallow cone design.
Magnetically Optimized Motor Structure: Through Alpine's advanced magnetic circuit design, this woofer offers better sound quality, and a higher sensitivity and power handling capability:
- Compound Radius Curve Pole Geometry: This patent-pending design intensifies the magnetic field for higher SPL and lower distortion. The magnetic field is balanced over a wider area for better control at high excursion.
- Extra Length Extended Pole: The extra long pole piece provides additional surface to capture radiated heat for additional power handling.
- Extra Thick Top Plate: This keeps more windings in the magnetic gap for better control.
- Double Stacked Magnets: These provide the powerful magnetic energy and extra depth for high SPL and maximum control.
- Bumped Back Plate: This "bottomless" design provides extra room for longer cone excursions.
- Optimally Saturated Pole: This reduces magnetically induced heat by eliminating eddy currents throughout the voice coil stroke, and evens flux distribution to eliminate "hot spots."
Cast Aluminum Frame: The woofer is mounted to a custom cast aluminum frame for added strength. This high mass frame also dissipates heat quickly to make it an integral part of the woofer's thermal management system.
Heat Transfer Plate: This subwoofer contains an integrated heat transfer plate that is thermally coupled to the voice coil. This plate pulls heat away from the voice coil and transfers it to the cast aluminum frame, achieving up to 20% additional power handling, and better reliability.
Dual Flare Pole Vent: Another part of the thermal management system is the unique dual flare design of the pole vent. This maximizes the flow of cooler air to the voice coil, and results in better power handling.
Dual Voice Coils: For increased system flexibility, the woofer has two 2-ohm voice coils. When the voice coils are wired in parallel with each other, the woofer presents a 1-ohm mono load. When the voice coils are wired in series with each other, the woofer presents a 4-ohm mono load. In addition, each coil may be connected to a different amplifier channel and each channel will see a 2-ohm load.
Spring Posts: The woofer has two pairs of spring posts which will accept pin connectors and up to 8 gauge bare wire.
Power Handling: This woofer has a total RMS power rating of 500 watts and a total peak power rating of 1500 watts. Each voice coil carries an RMS power rating of 250 watts and a peak power rating of 750 watts.
Recommended Sealed Box Volume: The sealed box sizes recommended by Alpine range from 1.3 cu/ft to 2.5 cu/ft. Within this range, the ideal size recommended by Alpine is 1.5 cu/ft, so this is the enclosure recommended by Crutchfield. According to the manufacturer, the 1.5 cu/ft enclosure will require at least 300-400 watts RMS power.
Recommended Vented Box Volume: The vented box sizes recommended by Alpine range from 1.5 cu/ft to 3.0 cu/ft. Within this range, the ideal size recommended by Alpine is 2.25 cu/ft, so this is the enclosure recommended by Crutchfield. One 4" diameter x 10" long port should be used with the 2.25 cu/ft enclosure.
Frequency Response: The manual lists the frequency response as "Fs-1kHz" (Fs=Free Air Resonance frequency). According to Alpine, the actual frequency response is 22Hz-1kHz.
Recommended Enclosures: The manual only lists the recommended sealed box volume range. The vented box volume recommendations were obtained directly from Alpine.