When thinking of high-performance subwoofers, the name Velodyne is probably the first that comes to mind, and for good reason. Velodyne has been on the cutting edge of subwoofer technology from their beginning in 1983. Since then, Velodyne has employed numerous new technologies to make subwoofers more accurate, including servo-control, advanced cone materials and, most recently, room correction in their Digital Drive series of subwoofers. Fortunately, Velodyne has decided to share their powerful room correction with owners of subwoofers from other manufacturers, too.

The $749 SMS-1 is a standalone device that uses powerful software to analyze and compensate for room anomalies, which reduce the performance of your subwoofer. The SMS-1 is inserted between your preamp/processor and the subwoofer by either single-ended or XLR connection. The SMS-1 uses a series of generated frequency sweep tones and an included microphone to determine how the signals interact with the room. The frequency response of the room is displayed onto your TV, which allows you to make manual corrections or, if you prefer, you can command the SMS-1 to do this automatically.

The difference that the SMS-1 made in my system was nothing short of jaw-dropping. I have a very high-performance subwoofer in my system and I always thought it did an excellent job. What I didn't know was just how much my room was hampering the performance of it. With it, my system creates kick drums that thump you in the chest, explosions that make the hair stand up on your arms and volume that makes my wife yell at me to turn it down.

The SMS-1 can store up to six different corrections that can be tailored for different types of music or movies. Each of these corrections are selectable in real-time via the remote control, and makes it simple to find the ideal response for specific listening material.

High Points
- The SMS-1 is extremely powerful, yet also very easy to operate. Simply connect it to your system, connect the microphone, let the SMS perform a self-tune and your subwoofer will instantly be transformed into a much better subwoofer.
- Multiple settings allow the user to have complete control over the way the system performs, depending on the type of material.

Low Points
- The remote control is rather large and not backlit, which makes using it in the dark nearly impossible. It's best to determine which sound correction setting you want to use before starting the movie and dimming the lights.
- When powering off, my subwoofer would emit a rather loud thump. The obvious way to eliminate this is to simply leave it powered on at all times.

Conclusion
The Velodyne SMS-1 is a superbly designed and built product. It allows the user to tweak the performance of the subwoofer to his or her heart's content. It also cleverly includes a self-tune function for those customers who want to plug and play. Regardless of what type of enthusiast you, are the SMS will make your subwoofer perform better and increase your enjoyment of your system.