Loudspeaker EQ

In January I started to look again at my GX300 crossovers. I use a handy program called Passive Crossover Designer which I feed with measurements taken with REW v5.1, both are freeware and really good in the latest versions in my opinion. I bought a U-MIK test mic recently and downloaded the calibration curve for my serial number and it led me to do a lot of driver and speaker testing before being ill.

REW's response curves, waterfalls, and other graphs are really interesting. I've written about them before in the room acoustics context so will not digress. I started to look at the distortion analysis this time and have been measuring various speakers in my collection with the sine wave sweep and also with two tone/intermodulation tests. Very interesting, especially when comparing closeup readings with listening position. The latter picks up more of the room's contribution obviously but also shows how being off axis can reduce the closeup distortion.

On my GX300, which I still enjoy, I am toying with adding the missing inductor to make the midrange LPF third order to match the third order HPF on the tweeters. I have rigged the extra part up to listen and to measure the impact, still not sure it's worth the admittedly limited effort to make the change properly. Temptation may overcome me yet...