This product is a vintage Polk model and is not available for sale, but it may still be available in some stores as a closeout or used product. The following text is taken from the original sales brochure for this product and does not reflect current availability. If you happen to have any question or concerns about this product, or any other Polk Audio product, feel free to contact our Customer Service Department at 1-800-377-7655 Monday - Friday, 9am - 5:30pm EST


5.25 inch two way system with external crossover

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The Ultimate Listening Experience


A great set of wheels deserves a great speaker component system.

Based on technology adapted from our top-of-the-line award-winning LSi in-home series, the Polk Audio SR5250 Signature Reference Series 5 1/4" Component System is for people who want the highest-performance sound for their high-performance car.


The SR5250 can be used either as a separate component system or converted into the best dang coaxial speaker on the planet. Each SR System includes mounting adaptor plates that allow the SR5250 to fit almost any application.

The tweeter can be used either as a separate component or post mounted coaxially with the driver. Two flush mount cups (straight and angled) and two coaxial posts (straight and angled) are provided for the ultimate in installation flexibility.


Award-winning Polk Audio technology places the SR Signature Reference Series at the apex of high-performance car audio. The drivers use aerated polypropylene cones for maximum stiffness and minimum cone resonance, ensuring a tight, clean, articulate response.

Nitrile butyl rubber surrounds, laser-optimized, vented 2-layer Kapton voice coils and formers, and case aluminum baskets with extra heat dissipating features, all contribute to the SR Series' professional sound quality and outstanding reliability.

  • Aerated Polypropylene Cone. The mid/bass driver cone is Aerated Polypropylene in which air is injected into Polypropylene to produce a honeycomb structure that serves to stiffen and damp the cone without adding mass. This is the same cone technology employed in Polk's critically acclaimed LSi Series audiophile-grade home speaker line.
  • Polyimide Voice Coil Former for high thermal stability (rated to 220°C) high power handling and low mass.
  • 1 1/2" Voice Coil For better power handling and bass output.
  • Butyl Rubber Surround
    Further damps cone resonance for wider response and lower distortion. High resistance to UV and temperature extremes means long life and reliability.
  • Removable Phase Plug
    For smooth, flat frequency response even off-axis. Remove the phase plug and replace it with either a straight or angled tweeter mounting post to transform the SR5250 into the absolute best coaxial speaker on the planet.
  • Neodymium Magnet Structure
    Finite Element Analysis (FEA) design makes the powerful neodymium magnet more linear for lower distortion and higher definition. Small Neo magnet makes the SR5250 easier to fit into more locations and vehicles.
  • Die Cast Aluminum Basket
    Provides greater resistance to resonance.
  • 2 1/2" Mounting depth plus supplied spacer rings ensure easy installation into a wide variety of cars.
  • U.S. & Euro hole patterns to line up with the mounting screw holes of virtually any vehicle.
  • 4-Way Gold Plated Input Terminals Corrosion resistant terminals accept fastons, spade lugs and bare wire.
  • Vent Holes in the basket equalize air pressure on both sides of the spider for more linear travel, flatter frequency response and lower distortion.


Polk's 22mm Ring Radiator Tweeters, usually found only in high-end home speakers, pack high performance and power handling into a small package.

A powerful Neodymium Motor Sturcture with Faraday Cap maintains consistent impedance, lowers distortion, extends and improves high frequency response.

The result is razor sharp detail, stunning accuracy, and top-end response well over 40kHz.

  • 22mm Ring Radiator Tweeter
    Ring radiator tweeters have inherently few performance-robbing resonance modes. The result is flat, extended frequency response beyond 40kHz, low distortion, excellent dynamics, exceptional detail and transparency.
  • Neodymium Motor Structure with Farraday Cap
    The copper Faraday Cap on the pole piece flattens the impedance curve, lowers distortion, extends and improves high frequency response.
  • High Frequency Waveguide
    Prevents phase cancellations for smooth, uniform frequency response and wide dispersion.


The SR Series outboard crossover features 2nd Order filters with the finest 1% tolerance parts including Mylar Film Capacitors and Air-Core Inductors. You hear better dynamic impact, more transparency, faster transient response and lower distortion. All of which adds up to utterly sublime music to your ears.

The SR components are easily bi-amped with seperate woofer and tweeter crossover inputs. Gold-plated terminals resist corrosion, and three levels of tweeter attenuation let you dial in the treble balance that's right for you.

  • Zoebel Network flattens the system impedance curve for more efficient power transfer and flatter response.
  • Air Core Inductors with Oxygen Free Copper wire, for wider dynamic range, contrast and punch.
  • Tweeter Protection Circuit.
  • Gold-plated connectors.
  • Mylar Capacitors better damping factor. 1% tolerance Resistors and Capacitors for perfect unit-to-unit consistency. 4-position Tweeter levels: +1, 0, -1.5, -3.
  • Cast-Aluminum heat sink chassis.
  • 2nd Order Low Pass Filter.
  • 3rd Order High Pass Filter.

*The Innovations Design and Engineering Award is based upon descriptive materials submitted to the judges. CEA did not verify the accuracy of any submission or of any claims made and did not test the item to which the award was given.

Driver Complement

Diameter1" (2.54cm) 
TypeRing Radiator tweeter 
Mid / Woofer
Diameter5 1/4" (13.34cm) 
TypeDynamic Balance driver with aerated polyproplyene cone 


Total Frequency Response60Hz - 30kHz 
Nominal Impedance4 ohms
Efficiency90 dB
Power Handling
Continuous100 watts
Peak200 watts

Thiele / Small Parameters

Resonant Frequency71 Hz
Xmax Linear0.1 
Xmax Mechanical0.362 
LE.25 mH
SD14.33 sq. in., 92.46 sq. cm. 
VAS0.2073 Cu. Ft., 5.87 L 


Cut-Out Diameter4 3/4" (12.06cm) 
Tweeter Cut-Out Diameter1 3/4" (4.45cm) 
Height1 1/8" (2.86cm) 
Diameter6 3/16" (15.72cm) 
Driver Mounting Depth
Top Mount2 1/4" (5.71cm) 


Unit of Measuresystem 


Speaker Warranty1 year parts and labor (original purchaser) 

Specifications, dimensions and features subject to change without notice. For more information call us at 1-800-377-7655 (USA and Canada). Outside of North America call +1 (410) 358-3600.

SR5250 Media

SR5250 Literature

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