Bookshelf Speaker Reviews

If there’s any speaker spec that’s routinely bogus, it’s bass response. You see a lot of little speakers rated to deliver bass below 40 Hz, but that measurement is almost always taken at -10 dB, instead of the industry standard of -3 dB. Even if the little speaker does hit, say, 36 Hz at some level, it almost certainly can’t deliver any usable volume at that frequency.

There are ways, though, to get legit sub-40 Hz response from a little speaker. One is H-PAS, or Hybrid Pressure Acceleration System, invented by Solus-Clements and now used and licensed by Atlantic Technology.

H-PAS employs internal resonating cavities that allow a speaker to deliver much deeper and more powerful bass response than a similarly sized, conventionally vented or sealed speaker could.

We saw proof of the H-PAS concept in Atlantic Technology’s AT-1 speaker. Even though it was pretty impressive that the AT-1’s bass output matched a lot of midsized subwoofers using only two 5.25-inch woofers, still, it’s a pretty big speaker. For H-PAS to impress me, I told Atlantic president Peter Tribeman, it would have to deliver big bass from a small speaker.

That’s just what the AT-2 seeks to do.

The AT-2 is the same size as a typical so-called bookshelf speaker (more accurately described as a stand-mounted speaker or mini-monitor), at just 15.75 inches high. It uses a 5.25-inch woofer — standard for this size of speaker. There’s a large slot port at the bottom. If I didn’t know there was something special going on inside, I’d have eyeballed this thing’s -3 dB bass response at maybe 50 Hz.

The 1.13-inch tweeter is the same Low Resonance Tweeter used in the AT-1. It uses a fat 4mm surround to give it more excursion, which in turn allows a lower crossover point and better dispersion. A tweeter level switch on the back allows you to raise or lower the tweeter output slightly to fine-tune the response to your room and/or your taste.