For years, cinema exhibitors struggled to reduce costs and maximize profits without sacrificing the customer experience. In areas like concessions, it’s easy to measure profit through the sale of popcorn, candy, and soda—but it can be rather difficult to quantify a return on investment for a world-class sound system.
In this article, we’ll explore the current state of cinema speaker performance and discuss how two-way systems can be designed to achieve a level of performance usually reserved for more expensive three-way solutions.
Two-way or three-way?
Three-way speakers are typically selected for applications where high output, good low-frequency response, and deep sub performance is required. This can be prohibitively expensive, especially for small and mid-sized rooms catering to smaller audiences. So, to reduce cost, many exhibitors choose to install two-way loudspeakers. Historically speaking, these two-way speakers provide less performance than their three-way counterparts—especially in the crossover.
By using a carefully engineered mold or “aperture” that’s integrated into the low-frequency (LF) driver of a two-way speaker, as in the JBL 200 Series, the system can provide a wider, more uniform coverage pattern so that the entire audience can enjoy improved frequency response—particularly in the mids where audio information is critical for intelligibility.
How does the aperture work?
Traditional two-way systems create a “beaming” phenomenon, which occurs in the mids produced by the LF driver. As illustrated in Figure A, the higher the frequency, the more pronounced this effect will be, with very narrow energy above 1kHz. In most standard two-way speakers, the mid frequencies ultimately suffer outside of the sweet spot seating area because the LF driver is trying to perform at a frequency that’s not very directional. The result is that anyone sitting outside the sweet spot will be missing significant audio information, particularly in the crossover range.
Now the Entire Theater is a Sweet Spot
What most theatergoers have realized, subconsciously or consciously, is that the known sweet spot in traditional audio systems is about two-thirds of the way back in a cinema, towards the center of the room. The sweet spot in traditional systems can be quite small—so if a blockbuster movie is released, it’s going to be difficult for most people to get a seat in that area.
The aperture (as seen in Figure B) widens the sweet spot area as much as possible, so whether you’re at the front, middle, or back, you’ll get a premium audio experience. There’s no longer a need to compromise or sacrifice just because the theater is full. And cinema operators can enjoy the affordability of a two-way system while providing three-way-type performance to audiences.
Do you have experience getting uniform coverage out of two-way cinema speakers? Share your insights in the comments.