The crossover design is the last, and most important part of any speaker. I have auditioned excellent drivers with a bad crossover design that sounded commensurately bad. I have also heard relatively cheap drivers with an excellent crossover design that sounded quite good. The crossover is the heart of any loudspeaker. Measuring the results of crossover modification is critical. These method of obtaining these measurements have changed in favor of the home enthusiast during recent years.
Once upon time.. accurately measuring the response from a loudspeaker required a large anti-echoic chamber. This is because the room reflections would interfere with the measurement. While anti-echoic chambers are nice to have, they are are expensive. They are also no longer needed for accurate measurements. They are rapidly being replaced.
Computer measurement hardware/software such as LAUD, LspCad, LspLab have made accurate measurement available without the use of large anti-echoic chambers. There are many methods of measurement using these computer programs, but the one that is most easily conceptualized is the Gated Time Response.
The Gated Time Response uses a timed gate for the microphone via a computer, soundcard and amplification. Perfect measurements are quite simple. The computer turns on the microphone and sends a frequency pulse (A) through the speaker. The microphone remains open/on and receives the frequency pulse. After receiving the pulse the computer closes/shuts-off the microphone. This happens before the arrival of the reflected waveform (B). The gated time response nullifies the effects of room reflections and provides a perfect representation of the speakers response.
The advent of this technology has made the home crossover designer a viable competitor in loudspeaker design. There is obviously much more to a good crossover, but this is the tool that brought the very best designs down to the level of the skilled home designer.