I received a curious email from another reviewer informing me about a subwoofer that I should look into. He assured me that he had not lost his mind but wanted to stress that the Pioneer SW-8MK2 was an absolute "killer subwoofer." With amazement, he stated that this subwoofer not only had a ridiculously low retail price of $160 each, but that it also outperformed his current subwoofer that retails for $2,000 apiece. After I made arrangements to review and began auditioning a pair of the Pioneer SW-8MK2 subwoofers, I began an online search for information about this subwoofer. I learned that legendary speaker designer Andrew Jones was brought in to revise the SW-8MK2 to its present state. I also ran across several threads concerning a company located in Oregon, called Stereo Dave's Audio Alternative, that had modified the SW-8MK2 subwoofer for only $150 to greatly improve its total sonic performance to an even higher level compared with the stock unit.

Much like Henry Ford's Model-T, the Pioneer SW-8MK2 only comes in matte black ash. The subwoofer's dimensions are 14.19 inches high, 12.19 inches wide, and 12.19 inches deep, and it weighs 20 pounds. It is driven by an internal 100-watt amplifier with a downward-firing eight-inch woofer cone and a port located on the front. A Pioneer logo sits underneath the port, and a blue LED indicator lights up when the sub is powered on. Behind the panel of the SW-8MK2 are the controls for setting the crossover point, volume, phase, and power. The SW-8MK2 can be driven either by your amplifier/receiver directly into an RCA connection or by tapping into speaker connectors that are also located on the back. Pioneer rates the SW-8MK2's frequency range from 38 Hz to 150 Hz. For a piece that only sells for $150, the physical appearance and built quality are quite good.

About two years ago, I reviewed the excellent REL Acoustics T-7 subwoofer, retailing for $1,000 a unit, and bought the review pair for my smaller system. While having a pair of subwoofers does lower bass extension and improve slam, the major advantage, when properly set up, is that dual subwoofers increase the soundstage in all directions. You also get much stronger image density and more three-dimensional aspects to the individual players. I set up the pair of Pioneer SW-8MK2 subwoofers in the same location as the T-7s, located on the outside corners of the Lawrence Audio Mandolins with the subwoofers two and a half feet off of the front wall. I kept the volume, crossover, and phase consistent between the two pairs of subwoofers. To my disbelief, the $320 SW-8MK2 pair performed at the same sonic level as the highly regarded pair of T-7 subwoofers. The SW-8MK2 produced all the sonic spatial qualities and offered as much bass extension and slam as the T-7 subwoofers. One aspect of the SW-8MK2's performance was even a slight improvement over the T-7 model: the accuracy of the tone and timbres of different bass instruments.

Excited to contact Sean Scoggin of Stereo Dave's Audio Alternative, I called him to discuss what his modifications were to the Pioneer SW-8MK2 and discovered that they use a proprietary method to influence and speed up the electron flow of the subwoofer's amplifier. Modifying the driver allows the subwoofer to move faster and have better freedom in its excursions for accuracy and speed in its ability to track the low frequencies it is replicating. All the modifications successfully work to quicken the subwoofer and increase its bandwidth/frequency range, making the subwoofer sound faster, more powerful, and deeper while still maintaining bass texture and detail.

When I got the pair of modified SW-8MK2 subwoofers from Sean, I set them up exactly as the stock pair had been set up in my system. To my amazement, I heard the sonic improvements in the first few moments of auditioning the modified pair. The modified SW-8MK2 subwoofers truly were much faster and more dynamic, they created deeper/flatter bass extension, and they had more accurate tonality in a natural way, making their integration with my Mandolins even more seamless. With this modification, the SW-8MK2 significantly outperformed my T-7.

High Points
• The Pioneer SW-8MK2 subwoofer is very well built for its price point and has the look of a more expensive unit.
• The stock SW-8MK2 offers terrific sonic performance in the areas of increasing soundstage dimensions, image density, and extension of lower frequencies.
• Its controls allow for hassle-free hookup and dial-in for seamless integration with your system.
• The modified version of the Pioneer SW-8MK2 subwoofer takes this already excellent performing unit to another sonic level across the board in speed, power, bass extension, and accurate bass tonality.

Low Points
• The Pioneer SW-8MK2 subwoofer only comes in a matte black ash finish, which might not match the color or wood grain of your main speakers.

Comparison and Competition
In today's market, I cannot come up with any subwoofer that costs only $160 and comes anywhere close to the remarkable performance of the stock Pioneer SW-8MK2. My REL Acoustics T-7 subwoofer, at $1,000 each, was equaled in performance by the standard SW-8MK2. Then, if you choose to have the SW-8MK2 modification done by Sean Scoggin's company for an additional $150 (plus shipping and handling costs), you have a subwoofer that performs at a sonic level that normally would cost you at least a couple thousand dollars. Either way, Pioneer and Andrew Jones have created one of the greatest bargains in a subwoofer for any two-channel or home theater system.

Conclusion
The Pioneer SW-8MK2 subwoofer offers remarkable performance, not just for its very inexpensive price but because it competes with much more expensive units. With the $160 stock model, the SW-8MK2 already has excellent bass extension and tonality. If you choose to have the SW-8MK2 modification done by Stereo Dave's Audio Alternative, you will have a subwoofer that outperforms rival models retailing in the thousands of dollars. The ultimate compliment a reviewer can give a piece of equipment is to purchase the piece he or she has reviewed, as I have done with the SW-8MK2 pair. I highly recommend putting the Pioneer SW-8MK2 on your short audition list, and I would consider getting it modified to improve its already excellent performance for a relatively modest price. Either way, you will get great performance and a great bargain.

Additional Resources
• Check out more subwoofer reviews in the Subwoofer Section at HomeTheaterReview.com.
• Pioneer SP-FS52 Floorstanding Loudspeaker Reviewed at HomeTheaterReview.com.