Anatomy of the Alpine SBR-S8-4 enclosed 8" subwoofer
Learn what makes this subwoofer sound so good

by Crutchfield's
Meet Buck Pomerantz

I belong to a culture of fine sights and sounds, and I like spreading the word.
I've been tinkering with electronics ever since I was a kid - starting with taking apart and putting back together televisions and radios. I always got them back together again and working. I took courses in radio and electronics as a teenager, and became a ham radio operator. I worked in my high school's stage crew, running sound, lights, and a movie projector. After college, I joined a rock 'n roll band as the soundman and learned how to lug around and operate the gear that helps make music sound good and loud.
Working in a music store in Austin, Texas, I spent a few years manufacturing, installing, repairing, and operating sound systems. Our customers were recording studios, nightclubs, and touring bands. Eventually I moved back to Charlottesville, Virginia and opened a small demo recording studio. In 2006, I finally came to my senses and got this job at Crutchfield. They actually pay me to ramble on, rant, and explain the things I love about music, electronics, and getting good sound.
Given my background, they put me to work writing about some of the most complex electronic products Crutchfield sells: car amplifiers, digital signal processors, wiring, professional sound mixers, and PA systems.
More about Buck
- Started at Crutchfield in 2006
- Completed our thorough in-house Advisor training, learning about the ins and outs of our various products
- Stays up-to-date by attending vendor training sessions for new products
- Earned MECP (Mobile Electronics Certified Professional) certification
- Designed and organized Crutchfield's subwoofer wiring diagrams
- Authored dozens of Crutchfield articles and hundreds of product presentations, primarily focused on car audio amplifiers and pro audio gear
- Answers the many customer questions posted in the comments on his articles
- Semi-retired soundman with decades of experience making other people sound good
- From 1999 to 2018, also worked as a sidelines video camera grip for University of Virginia football and basketball games
More from Buck Pomerantz

Add some bass, save some space
Alpine’s SBR-S8-4 ported subwoofer gives you the hard-hitting bass your system was missing — without taking up the valuable storage space you need. The slim box makes placement easy — it’s only 6-5/8" deep, so you can install it behind the seat in a standard-cab pickup, and in many other places in small vehicles.
This enclosure is tuned by Alpine’s experts to give you impressive bass with minimal power requirements. The high-quality, medium density fiberboard (MDF) enclosure, internally braced to add stiffness and durability, perfectly matches the 8" Type-R subwoofer, guaranteeing maximum punch while maintaining a small profile.
More cone movement means louder, deeper bass
The High-Amplitude Multi-Roll surround (HAMR, patent pending) allows the cone to move much farther forward and back than a typical surround. This pushes more air, for louder, deeper bass. Its unique shape also lets Alpine put a larger cone in the standard-sized frame.
Plays cool, lasts longer
A subwoofer’s voice coil puts out a lot of heat when it plays, which could damage the sub if not taken care of. Alpine’s patented “Radial Vented Voice Coil Heat Sink & Airflow Management System” uses the motion of the sub itself to suck cool air in and force hot air out, extending the life of the sub.

Massive magnets control accuracy
The power to create music that sounds clear and free of distortion depends on the strength and shape of the magnetic field in the sub’s motor assembly. Alpine packs each Type-R sub with a 10-piece segmented magnet made of strontium ferrite that emits a large field, while maintaining a compact profile.
The shape of the pole piece focuses the magnetic field in the voice coil gap, reducing distortion. It also doubles as an air vent used in the cooling system.
A guide for the bass tones
A ported subwoofer enclosure allows sound from the rear of the woofer cone to travel out of the port and join the sound coming from the front, increasing loudness and enriching the tone. A reason ported subs hit so hard and deep is that the air flowing in and out of the port creates an audio effect like that made by blowing across the mouth of a bottle. That tone adds to and strengthens the note the cone plays.

The wraparound port
There’s no rule that says a port has to be straight, and Alpine cleverly made this one wrap around to save space and keep the enclosure compact. The flared port entrance helps prevent audible “huffing” as air goes in and out. The slanted construction of the port exit serves the same purpose.

Fits in and hits hard
The Alpine SBR-S8-4 8" subwoofer will fill your ride with cool bass no matter where you put it. Carpet covering protects the enclosure from nicks and scratches, while a metal grille guards the cone against any other hazards in your car.
Want one? Get yours today. Or give us a call if you have any questions.
RANDY B from SAN DIEGO
Posted on 9/9/2019
If it was powered it would cost more. I think this is an awesome system. It leaves it to you the owner to power it with your choice of amplifier. That way you can customize it's output to your own personal taste. I'm not a big fan of powered subwoofers anyway
Keith from Nacogdoches
Posted on 8/16/2015
If it was powered it would be awesome.