How Much Are You Missing From 20khz to 45khz?

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Kr4, do you think there's any value or advantage for a speaker to be able go above 20khz?
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Kr4
Do you hear any difference between a CD and SACD?

12-27-12: Mitch4t: Kr4, do you think there's any value or advantage for a speaker to be able go above 20khz?

I think that it is necessary that speaker response extend at least to 20kHz and have a smooth, well-behaved rolloff above.

12-27-12: Don_c55: Kr4
Do you hear any difference between a CD and SACD?

I do but I doubt that it has to do with FR. For example, at an audio show, I was able to pick out the addition of an ultra-tweeter that was effective only above 20kHz even though I have audiograms which show that my hearing at 20kHz is more than 20dB from reference.

The SACD improvement over CD on most recordings i feel relates to improved digital processing and frequency response, that I easily hear on my Magnepan ribbon tweeters which go to 40 kHz. On phono, MC improvement over MM, more clearly relates to FR. IMO the difference comes down to more accurate complex harmonic structure in the audible higher frequencies under 20 kHz. Most all audiophiles prefer SACD over CD, and MC over MM.

The less phase shift, the better the imaging.

Tonality will also improve since phase shift causes improper summing of harmonics. I'm not sure about speakers but amplifier has at least 45 degree phase shift at -3dB frequency limit. My -3dB@60kHz amplifier has 20 degree phase shift at 20kHz. Newest amplifiers from Jeff Rowland have 350kHz bandwidth.