@phusis wrote:
"The EV Constant Directivity horns (HP9040 + DH1A) on my EV main speakers, by virtue of not narrowing the HF response on-axis, should require equalization in its upper band above some 3kHz, at least for their intended cinema use, but surprisingly we’ve only found it necessary and most important to apply some notches and a peak suppression via a Xilica DSP (active config.)... What’s your assessment here?
The short answer is, I don’t know.
Perhaps the crossover filtering is providing the equalization without obviously using a dedicated EQ circuit, by cutting the lows instead of boosting the highs. Perhaps EQ is being applied somewhere without you knowing about it. Perhaps your compression drivers have signifcantly better frequency response than the published curve; I have found that to sometimes be the case, the manufacturer apparently having made unannounced improvements in the frequency response... but usually not to that extent. I don’t see an impedance curve online, perhaps there is an amplifier interaction with the impedance curve which results in a rising top end with your amp, or which resulted in a drooping top-end when the published curve was measured.
That being said, the published unequalized curve for that horn/compression driver combination looks right to me. It looks like the curves I get with large-format compression drivers on constant-directivity horns.
All of the above speculative explanations are unlikely, perhaps even highly unlikely, which brings me back around to "I don’t know".
Sorry about that!
Duke