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--- namespace:speaker_directivity_and_room_eq [2025/12/15 20:26] – [Speaker Directivity and Room EQ] tim
+++ namespace:speaker_directivity_and_room_eq [2026/01/21 02:23] (current) – [Speaker Directivity and Room EQ] tim
@@ Line 16: / Line 16: @@
 In summary, I've found a way to return my speakers to their original design configuration and have them sound very pleasing by NOT equalizing the output of the mid-horn flat at nearfield. I will continue to listen and perhaps tweak the equalization of the mid horn to result in a more gentle slope at the listening position and find out if that's better or worse. I've got a lot of questions remaining. Why doesn't it perceptually sound unnaturally dull when listening off-axis, or in another room? The upper frequencies being so narrow should be adding less total energy to the room. Somehow I'm not perceiving it as at all unnaturally "dark" sounding anywhere in the room or in adjacent rooms. It's really nice and easy on the ears. It also can get a //lot// louder because the EQ requirements are greatly minimized, and the tweeter isn't being asked to go so low.
+Update December 22, 2025
+I tried to adjust the room slope at the listening position to 0.5 dB/octave. This sounds too bright. I've also tried to model the fall-off rates for narrow vs wide dispersion drivers and the results are not showing a consistent brightening. This may be a specific problem with my room and the specific characteristics of the speaker I'm using. Fall-off rate is not intrinsically about directivity. It's more about the curvature of the wave front. It's possible to have a narrower pattern that is still made by a curved wave front, which means it will have the same fall off rate as a wider dispersion pattern that has the same wave front curvature at any given distance. As we move away from a small plane source we see that it's wave front curvature becomes very close to the same as the curvature of a point source at the same location. It's only up very close that this fall off rate differs a lot. This may be why 2 meters is considered sufficient for on-axis measurements. The anechoic on-axis response shouldn't change much with distance after that for most any "normal" speaker.
+My simulations did suggest that room acoustics can have some surprising effects, with diffusion being typically more effective on high frequencies than lower, this could mean diffusive elements can beam more high frequency energy back to the listener. If the walls are bass leaky, this could result in a brighter than expected response at distance, although the same would hold true with a speaker that was not beamy up top.
+I'm starting to suspect that the reason my speakers need a fairly steep room curve is due to the fact that for the anechoic response to be flat on axis at the listening position, the off axis energy in the lower frequencies is actually quite a bit higher. My problem may be that I don't have any way to get the anechoic on-axis response at 2 meters because of room reflections, so I'm really shooting in the dark and getting confused by the reflections creeping in. I had better luck by starting with an no-EQ result and then working backwards from there. I suspect now that if I could figure out how to get the on-axis anechoic response for the speaker what I like the sound of would actually look pretty flat.
+Update January 2, 2026
+It turns out that I can't seem to get a sound I really like that makes much sense in terms of ancehoic on axis response being prefectly flat for each driver. I'm not sure why, but it always seems best if I don't EQ the speaker drivers, but only set the crossovers and adjust their levels by ear. The end result in this room is a fairly steep room curve as noted earlier, but with some specific frequency cut backs as a room treatment.
+Update January 20, 2026
+Somehow I now am EQing the drivers flat fairly nearfield and I am liking the sound. I should never be a speaker reviewer. I don't know if it's my perception that changed or what but now I'm liking the sound with the coaxial tweeter EQ'd flat on-axis measured at 2 meters and crossed over all the way down at 600 Hz to the mid-horn, which is also EQ'd flat from it's 600 Hz crossover down to about 130 Hz. I don't understand what changed, but now at least this makes some sense. It actually sounded prettty good with a large overlap between the mid and tweeter, covering from about 1000 Hz to 5000 Hz working together. It was a little crunchy sounding at times but very present and lively and not strident or overly sibilent. Not perfectly neutral but very easy on the ears and worked well for me with everything I listened to. With the 600 Hz crossover I avoid dips in the off-axis response. Instead the off-axis starts sloping down at about 700 Hz or so in a straight line. This also sounds good. Not quite as punchy and intense but seemingly smoother, less colored.