Thanks for posting that frequency response curve. I agree, it's a heck of a rising swing.
That figure is taken from a December 2015
Stereophile review Paradigm Prestige 95F speakers. Our friend in the Netherlands says he's interested in the Prestige 85F, the smaller brother of the 95F. They look to be similar designs, but the 95F has 8" (203 mm) woofers & mid-woofer, and the 85F has 6½" (165 mm) drivers. It is possible that they share the same tweeter. The 95F is a 2½-way speaker, where all three of its 8" drivers operate in the bass. The two lower woofers roll off above 400Hz, while the topmost 8" cone, operates as a mid-woofer, continues alone up to 2kHz, where it hands off to the tweeter. The 85F speaker, also a 2½-way design, has crossover frequencies at 500Hz and 2kHz.
That same review also showed this frequency response curve where the green trace shows the responses of the three 8" woofers, and the red trace shows the response of the tweeter. The blue trace shows the port responses.
View attachment 60686
I see 3 peaks and I'm troubled by 2 of them. They are not what I'd like to see in a smooth sounding speaker. Do they indicate tweeter harshness?
- Between 600 and 1,000 Hz, the green trace drops and then rises rapidly to a peak between 1000 and 2000 Hz. Depending on the music and volume level, I think that peak could be heard. Because that is coming from the 8" mid-woofer, I wonder if that is cone breakup resonance. If so, that might be perceived as unwanted noise, or harshness. The peak is a high enough frequency for listeners to mistakenly blame the tweeter. That's in the larger 95F speaker. Would we see something similar with the 6½" mid-woofer in the 85F? Perhaps not. I'd prefer to see a frequency response graph.
- The red trace from the tweeter shows a broad rising response above 3,000 Hz. It peaks between about 5,000 and 13,000 Hz. That might be heard as brightness, but I don't know if it would sound harsh. Above 5,000 Hz, there is much less much less content in most music. If this tweeter of the 95F is the same as in the 85F, it could be trouble.
- There is a sharp peak above 20,000 Hz. That is common to metal dome tweeters, and I'm not concerned about it. It's not audible.