Introduction

The new line of drivers from SB Acoustics has received a lot of attention. They are well-built with an affordable price. Early test reports were good and caught my interest. When John "zaph" Krutke offered to let me test a pair of the tweeters, I didn't hesitate. He has since donated a pair of the 6" (OK, 170mm) woofers so that I could work up a design. "The Chameleon" is the result of that effort.

Why "The Chameleon"? It's not because it disappears the way a Chameleon can, no 2-way system stands a chance of doing that. A Chameleon changes its colors in an attempt to blend in with its surroundings. The T/S parameters of the SB midwoofer allow it to be used either closed box or bass-reflex. More to the point, the same box size can be appropriate for either case. This means that it can be used bass-reflex initially and have its "coloration" changed to closed box by simply covering or sealing the PR or a port if used. This lets it "blend into its surroundings" more easily if it's moved, say, from out in the room to nearby a wall.

In addition, several crossovers have been developed as options. The two best ones just happen to have nearly identical topologies and even share the same large inductors (read expensive). Converting from one to the other doesn't require a complete repurchase/replacement of all components. The two sound similar, but not identical and give the option to "change" the coloration more easily than most systems, so-to-speak.

These drivers are capable of good sound in a good design, limited bass notwithstanding. They do what many consider the most important, they do the midrange right. Vocals sound natural, there's no excessive sibilance, they don't have an "etched" sound (if that descriptive makes sense) and the timbre of acoustic instruments (on good recordings) comes through. They just won't do bass. But how many 6.5" drivers can?

It took a while to get the best from them. When one considers the driver cost they're even more impressive. One caveat is that the flattest crossover is a bit more complex than one might want for drivers used at this price point. Another is that the system sensitivity had to be dropped more than some may prefer. You'll want an amp with a reasonable amount of power, I'd say one rated a minimum of 100W into 8 ohms.

There are several crossover options. I tried to reduce parts count and have component values that are directly available as much as possible, but none are the simple ones often found with inexpensive drivers. The audible differences between the crossovers are relatively small, somewhat of a surprise. The tweeter crossovers are also a bit unconventional in one way. I've rolled off the tweeter top end to tame it to my liking, but adjustments for personal taste should be easy.

One thing that some may find helpful is that they integrate reasonably well with a subwoofer crossed roughly where many cost-effective subs do, around 85Hz. My tests were with an active woofer, not a sub, but these might work in a sub-sat setup. I hope to test them in that configuration at some point. I'll update this if and when I do that.

We'll go through the design from concept to completion. I've tried to include as much detail as is reasonable.