Your cart
Contact us
Close contact box
July 4
Crutchfield's website is open today, but our staff has the day off to observe Independence Day in the U.S.
Connect ID #
669 445 839 3
Connect ID #
669 445 839 3
All finished with your chat session?

We’ll email you a transcript of this conversation for your records.

Our contact center is currently closed.

Please enter your name.  
Please enter a valid email address. Why is this required?

For Tech Support, call 1-888-292-2575

Thank you, !
Our conversation will be emailed to
Chat Advisor Image

Your Advisor,

More about me
Please enter a question  
Don't wait on hold. We'll call you back when it's your turn to talk with the next available .
Please enter your name  
Please enter your phone number  

Please enter a message  

Calls may be recorded for training and quality control purposes.

We are located in Virginia USA.

Infinity Kappa Perfect 5.1

5-1/4" component speaker system

Item # 108PERF51

Sonic sizzle from Infinity!

Find what Fits your vehicle

Sonic sizzle from Infinity!

Discontinued item

Item # 108PERF51

Since 1974

Years of experience making people happy.

Car-specific installation packages

Deep discounts on the essential accessories that help your new gear work with your car.

Hands-on research

We double check the details on each item.

About the Infinity Kappa Perfect 5.1

Sonic sizzle from Infinity! The Kappa Series Perfect 5.1 5-1/4" component speaker system delivers stunning detail and pinpoint accuracy from deep-anodized-aluminum woofers and tweeters that hold their shape regardless of power level, ensuring superior clarity of output for years.

Sonic sizzle from Infinity! The Kappa Series Perfect 5.1 5-1/4" component speaker system delivers stunning detail and pinpoint accuracy from deep-anodized-aluminum woofers and tweeters that hold their shape regardless of power level, ensuring superior clarity of output for years.

Each 1" tweeter features an edge-driven, anodized-aluminum dome suspended by a butyl rubber surround. A powerful neodymium magnet drives the tweeter for clean, shimmering highs. Infinity's patented I-Mount tweeter-mounting system allows for easy flush, angled, or surface mounting.

A precision outboard crossover is used to divide frequencies seamlessly between the woofer and tweeter (24 dB/octave high-pass/low-pass at 3,500 Hz). You can adjust the tweeter output level to maximize system performance and imaging based on location.

The Perfect 5.1 system can handle plenty of raw power (up to 100 watts RMS), making it a great choice for the enthusiast looking for a system that will sound every bit as good at high output levels as at moderate ones.

Priced per system

Product highlights:

  • deep-anodized-aluminum woofer cone with butyl rubber surround
  • 1" edge-driven, anodized-aluminum dome tweeter
  • I-Mount tweeter mounting system for flush, surface, or angled mounting
  • 2-way crossovers (high-pass/low-pass at 3500 Hz, 24 dB/octave) with selectable tweeter output
  • frequency response: 80-23,000 Hz
  • recommended power range: 25-100 watts RMS (400 watts peak power)
  • sensitivity: 89 dB
  • top-mount depth: 2-7/16"
  • warranty: 3 years
  • Our 60-day money-back guarantee

What's in the box:

  • 2 Woofers
  • 2 Grilles
  • 2 Grille rings
  • 2 Crossovers
  • 2 Tweeters (each tweeter has attached 10" speaker leads)
  • 2 Flush-mount cups
  • 2 Threaded flush-mount adapters
  • 2 Plastic locking nuts
  • 2 Surface-mount cups
  • Two 0.205" female quick-slides
  • Two 0.110" female quick-slides
  • Eight 1" self-tapping screws
  • Four 5/8" self-tapping screws
  • Four 7/16" self-tapping screws
  • 2 Nuts
  • 4 Clip washers
  • 8 Speed clips
  • Instructions
  • Warranty/registration card

Customer reviews

Loading reviews...

Infinity Kappa Perfect 5.1 reviews

Average review:

5 reviews

Thanks for submitting your review

Filter by rating

Customer photos

Sort reviews

Sort by:
Items per page:
View page:

Verified customer (What's this?)
Verified employee purchase (What's this?)



Crutchfield response

<< >>

More details on the Infinity Kappa Perfect 5.1

Pat M.

Features & specs

Speaker Size
Design 2-way
Tweeter Design 1" Dome
Impedance (Ohms) 4
Tweeter Composition Anodized-aluminum
Woofer Composition Anodized-aluminum
Woofer Surround Butyl rubber
Parts Warranty 3 Years
Labor Warranty 3 Years
Sensitivity (1W at 1 meter) 89
Sensitivity at 2.83 volts N/A
Frequency Response 80 - 23k Hz
Minimum RMS Wattage 25
Maximum RMS Wattage 100
Peak Power Handling (Watts) 400
Top-mount Depth (Inches) 2 7/16
Bottom-mount Depth (Inches) N/A
Cutout Diameter or Length (inches) 4 11/16
Mounting Height (Inches) 0.478

Product Research



Woofers: The deep-anodized-aluminum woofer cones ensure incredible detail and accuracy. This material holds its shape regardless of output level, unlike more commonly used materials.

Surrounds: The butyl rubber surrounds have greater internal loss than standard urethane, preventing harmonic distortion at higher frequencies. The butyl rubber more efficiently absorbs edge reflections that can cause audible distortion, resulting in clearer bass performance.


Tweeters: Each 1" tweeter features an anodized-aluminum dome suspended by a rubber surround. The tweeters are driven by a powerful neodymium magnet, resulting in higher power handling and superior detail. The rubber surround helps reduce the resonant frequency of the tweeter, giving you cleaner, more accurate sound reproduction.

"I-Mount" Tweeter Mounting System: Surface mounting involves mounting the surface mount cup (using the supplied screws), then snapping the tweeter into the cup. Flush mounting is made easy through the use of the threaded flush mount adapter and plastic locking nut. For flush mounting, the tweeter is snapped into the flush mount cup. Then, the cup is secured to the flush mount adapter with a nut and clip washer. Once a cutout is made, the flush mount adapter (with the tweeter installed) is inserted into the hole. The large plastic locking nut is threaded onto the adapter (from behind the mounting surface) to hold the complete assembly securely in place. When flush mounted, the tweeters may be angled for optimum response and imaging. There are no provisions for angled surface mounting of the tweeters.

Tweeter Mounting Dimensions:

Surface Mount Flush Mount
Mounting Height 1.006"   0.628"

    (0.334" screw depth)

Frame Diameter 1.643" 2.005"
Cutout Diameter   NA 1.768"


2-Way Crossovers: Each crossover features a 24dB/octave, 3.5kHz high-pass network for the tweeter and a 24dB/octave, 3.5kHz low-pass network for the woofer.

Selectable Tweeter Output Level: Each crossover has 3 adjustments that allow you to select the tweeter output level according to system requirements and personal preference. The adjustments may be set to "-4dB", "5dB" or "0dB".

Crossover Connections: The crossover inputs and outputs are gold-plated screw terminals.

Mounting: There are four mounting holes in the base of each crossover.

Crossover Dimensions: W=5.913", H=1.546", D=4.485"

Loading accessories...

Customer Q&A

Loading articles...

Compare the sound