I agree completely with Mrtennis here and in experimenting through the years, especially with Quads, but also with other ELS, the only really satisfactory (to my ears of course) top end was found with the tweeter panels of the long defunct Servo Static speakers, which I tweaked, so I could attenuate them. Later with the Quad63s after much experimentation I settled with the aCapella plasmas which I placed on top of the Quads and drove them separately so that I could adjust their SPLs. They go up to 35khz. For the bats there of course, but the addition of these speakers had a tremendous influence (positive in the sense of more natural) on the entire sound stage and the rendition of transients, bloom,overtones and ambience .
Another thing is to be considered: Experiments have shown (unfortunatly I don't remember where I read about this, so I cannot point you to this, it was about 20 years ago), that listeners, unable to hear tones above 10khz, felt uncomfortable when music was played to them with its upper freqencies cut off above 18khz. So even if we cannot hear it, we obviously feel something is missing, when it is not there. So I personally am not a believer in fixed roll off points in the highs, but prefer, as MrTennis suggests, if I read him right, to set the highs myself, so that I have all the liveliness and ambience I wish for, without the sound per se getting thin, even if it practically means to set up a second chain to do so. (By careful placement, phase anomalies can be easily avoided)
At the moment, from what I've measured, the Sound Labs seem to start attenuating close to 20khz in my room and to me they sound just right. I still have the aCapella tweeters and will in due course experiment with them, driving them with the Zanden9600s to see what happens andI shall report, Nil, if you are interested.
Another thing is to be considered: Experiments have shown (unfortunatly I don't remember where I read about this, so I cannot point you to this, it was about 20 years ago), that listeners, unable to hear tones above 10khz, felt uncomfortable when music was played to them with its upper freqencies cut off above 18khz. So even if we cannot hear it, we obviously feel something is missing, when it is not there. So I personally am not a believer in fixed roll off points in the highs, but prefer, as MrTennis suggests, if I read him right, to set the highs myself, so that I have all the liveliness and ambience I wish for, without the sound per se getting thin, even if it practically means to set up a second chain to do so. (By careful placement, phase anomalies can be easily avoided)
At the moment, from what I've measured, the Sound Labs seem to start attenuating close to 20khz in my room and to me they sound just right. I still have the aCapella tweeters and will in due course experiment with them, driving them with the Zanden9600s to see what happens andI shall report, Nil, if you are interested.