SongTower transmission line cabinets are a sleek 8" wide, 11.25" deep and 44.5" tall (not counting plinths and spikes). The design begins with the Hiquphon OW2 tweeter. One of the finest 3/4" dome tweeters being made today, the OW2's smaller cone allows it to produce a more detailed and accurate top end than a typical 1" dome tweeter. Of course, it will not cross as low as a 1" dome. That is where the ER15's come into play. These high-performance 5" drivers have a very extended and flat top end, making them a perfect match for the OW2's. Of course, 5" midwoofers to not typically play all that low. That is where the SongTower's "Quarter Wave Tube" transmission line cabinet comes into play. Paul Kittinger did a marvelous job utilizing Martin King's mathcad formulas to develop the perfect TL cabinet for the SongTowers. This cabinet design allows the woofers to play lower than they would in a typical ported cabinet. The result is deeper bass than one would expect out of a speaker with 5" drivers. The combination of the drivers selected, the transmission line cabinet and Dennis Murphy' crossover design come together in a formidable speaker indeed. The SongTower's frequency response is 42Hz to 20,000Hz +/- 3db. And the response is very flat - even off-axis! Check out the SongTower's specifications.