K Series Features Tour

Directivity

There is an important relationship between woofer size and waveguide coverage pattern but it is frequently overlooked. It's known that all woofers have very wide coverage at lower frequencies and narrowing coverage as frequency increases. The smaller the woofer, the wider its coverage will be at a given frequency. However, many speaker designs simply ignore this acoustic principal and pretend that only the high-frequency horn coverage matters. But in reality, a smooth, directional transition from woofer to high-frequency is important in terms of consistent audience coverage and loudspeaker power response.

K Series is designed using the Directivity Matched Transition (DMT) approach. DMT matches the high-frequency coverage angle to the natural coverage angle of the woofer at the crossover frequency. As a result, frequency response remains far more uniform across the entire audience area.

The chart below shows the three K series full-range models (violet, blue and red lines) along with a theoretical 15" 2-way speaker (the black and gray lines) using a 50° x 100° horn and a crossover frequency of 2.2 kHz. As you can see, the horizontal coverage of this speaker dives all the way down to 50° before the high-frequency horn takes over and brings it back to 100°. What this means is that listeners who are more than 25-30° off axis won't be hearing much of the mid-range content (like vocals or instrumental solos) at all.



This brings us to the next point. Many manufacturers offer speaker models with smaller diameter woofers. But typically those components are lower cost and inferior in performance compared to their larger-woofer siblings. QSC took a radically different approach by maintaining the same high performance level across the entire K Series line, regardless of woofer size. Each is powered by the same 1,000 watt amplifier module.

The K8 delivers wide 105° coverage making it a great choice for performers who work in more intimate venues where the audience is closer to the stage and spread more widely.

The more directional K12 with its 75° coverage is a better choice when more "throw" is needed.

The K10, of course strikes a fine balance between both width and throw. No matter which model you select, you'll get flat frequency response across the entire coverage area.