measured the frequency response of the Rogers LS5/9 as being 65Hz to 21kHz ±4dB with the tweeter’s level set to 0dB, which is the response that’s shown in Graph 1. You can see that the frequency response almost tracks the 90dBSPL graphing line right up to 6.5kHz after which there’s a slight lift in the tweeter response that comes back down to the 90dBSPL line at about 12kHz then drops below it and remains at the same level out to 18kHz
