TBI Audio Systems bowled us over last year with its passive Majestic Diamond speakers; the company recently sent us the follow-up to those speakers (the Majestic Diamond IR) along with the new hybrid-powered Millennia MG3 Class D amplifier. (Buying the components as a package shaves $100 off the cost of acquiring them separately.)

Hybrid power means the amp can operate on either A/C power (using the included power supply) or eight AA batteries (not included). Plugging in the power adapter shuts off the batteries (but it won’t refresh any rechargeable batteries you might be using). Add a set of strong passive speakers and a digital media player capable of playing tracks encoded using a lossless codec (we used Cowon’s FLAC-friendly A3) and you have a fabulous audio system you can listen to just about anywhere.

The $500 amp’s faceplate features an oversize volume control knob, a power switch, and an 1/8-inch stereo input, which makes it easy to plug in a digital media player if the amp is on a bookshelf. An LED glows blue when the amp is running on AC power; red while using batteries. There’s a set of RCA inputs in back, along with a pair of five-way binding posts. The provided power supply is designed to drive eight-ohm speakers, but the amp can handle a four-ohm load if you use the optional 12-volt power supply.

The new single-driver Majestic Diamond IR speakers ($600) look exactly like the first-generation Majestic Diamonds, but they feature a new port design that TBI claims delivers improved low-end frequency response (60Hz, compared to the earlier design’s 70Hz) and drivers that deliver much better frequency response at the upper end of the scale. After extensive listening tests using FLAC files played on the Cowon A3, we agree with TBI’s claims.

Although the brick-sized amp produces just 40 watts per channel (with less than one percent total harmonic distortion), it puts out such full-spectrum sound it rivals much larger systems. (The unit produces 10 watts pwer channel while running on batteries.) Audiophile-quality sound systems, however, aren’t as unusual as they once were. B&W’s Zeppelin iPod powered speaker dock, for example, set the performance bar very high: It’s about $400 cheaper than the $1,000 Millenia/Majestic Diamond IR combo and it sounds better. That makes it tough to give the Millenia/Majestic Diamond IR combo a higher recommendation.

Editor's note: This article has been updated to correct an error in pricing (we had reversed the prices for the amp and speakers if purchased separately). We also needed to clarify that the amp produces 10 watts per channel while running on batteries; it produces 40 watts per channel when plugged into an electrical socket.--mb 8/27/2008

TBI Audio Systems MMD-1R

Grass-Fed Beef

Terrific sound from a very small package.

Corn-Fed Beef

Expensive; sound quality falls short of the cheaper B&W Zeppelin.

TBI Audio Systems