The Small Speaker challenge

When the small "bookshelf" loudspeakers became popular some 30 - 40 years ago, they established a new market niche. Stereo setups could now much more easily find their way into normal living rooms. Many of these small speakers did not impress with their sound quality, however, although there were exceptions. On the other hand, most small boxes were aimed at a consumer market where the requirements on sound quality were low, if any at all. However, many small studio monitors, for example, meet very high standards on several parameters. Lennart Jarlevang was approached by the owner of a mid-prized high fidelity loudspeaker of small size (net volume about six liters). The owner liked the basic tone and performance of the speaker very much, but complained about an annoying chill and harshness in the high frequency area. Initially thinking that this, as often is the case, was a tweeter issue, Lennart soon found the problem to be caused by a more interesting phenomenon. He set out to unravel the riddle and to modify the design for even better performance.