This is the new top-of-the-line full-range model in the PINNACLE^® line, which starts in the two hundreds and includes all kinds of speakers--stereo, home theater, in-wall, subwoofers, etc. It is a vented system, with three fat diagonally slanting tubes called Diaduct acting as ports in the back, and four drivers: two 8-inch woofers with paper cones and rubber surrounds, a 5 1/4 inch midrange with the so-called Aerogel treatment, and a 1-inch Ferrofluid-cooled metal-dome tweeter. The crossover frequencies are 500 Hz and 5 kHz; the network is quite complex, with filter slopes and shelving circuits tailored to the drivers, and build with high-end components such as air-core coils and polypropylene capacitors.  . The speaker is rather tall (44 in.), quite narrow (9 1/2 in.), and of moderate depth (15 in.).

One of the most difficult tasks a speaker designer can set for himself is to engineer a monolithic system with a small footprint that does it all, covering the full audio spectrum with high efficiency and low distortion, while keeping the cost within reason.  It's a delicate balancing act, which the PINNACLE^® engineering team (headed by Richard Rothenberg and Peter Moore) has executed about as neatly as I've ever seen.  This is a genuinely excellent all-around loudspeaker system a discriminating audiophile can live with and not go into debt.

The frequency response of the unit is best measured on the tweeter axis, as it is less good on the midrange axis. Interestingly enough, the 1-meter response improves in the stereo position, 30° inboard. In the 0° position the tweeter level is set too high, and average of 3 dB above the midrange level. The midrange response itself is very flat up to about 3 kHz, and the tweeter response is also reasonably flat up to 14 kHz, but there is this distinct upward step in the 3 to 14 kHz band, which looks much better 30° off axis. In the latter position I would characterize the response as +/- 2 dB right up to 16 kHz, except for a 5 dB dip at 3 kHz. The low-frequency response, as aided by the Diaduct port, appears to be quite flat down to 26 Hz but is hard to measure accurately because of the opposite-firing woofers and ports. The vented box is tuned to approximately 35 Hz, maybe a little lower.

I measured the distortion of the system only at the 1-meter SPL of 90 dB. At that rather loud level the tweeter is virtually distortionless, fluctuating between 0.06% and 0.13% THD. The midrange is also clean, 0.07% to 0.5%.  The woofers, naturally, distort a little more, 0.2% to 1%.  I think these THD figures are outstandingly low.  Needless to say, the speaker can play a lot louder than 90 dB; it is also more efficient than most.

The impedance curve of the system fluctuates between 3.4 Ohms and 15 Ohms in magnitude (8 Ohms nominal) and +/- 40° in phase, with smaller swings than that over most of the audio range.  Just about any decent amplifier can drive such a load.

The sound resulting from the sum total of the above characteristics is essentially neutral, highly defined, transparent, and dynamic. The bass is particularly excellent; no subwoofer is needed, certainly not for music. If I wanted to nitpick, I would perhaps point out a very slight heaviness in the lower midrange--or is it the upper bass? It may be due to floor reflections but is in any case quite minor, not enough to trigger an investigation. Bottom line: if a tall, floor-space-saving, full-range speaker is what you need in your room and the price is in the ballpark for you, I can unreservedly recommend the (what a mouthful!) PINNACLE^® Classic Gold Aerogel Tower.