Yes most hifi over the years including digital is designed to work well from 20 hz to 20khz the standard range usually considered appropriate for human ears. Anything above that is even more of a potshot than that extreme already may be.
A lot of potentially fatiguing noise can occur naturally in that range so that is something worth considering case by case....how much better sound versus noise as a result.
Also if the device has response down to 10khz then it would seem best applied in systems that can use a boost in that upper range which with music is where "air" occurs. The result would likely be a sense of more "air" and perhaps a tad more "pierce" in that case which many might find desirable in some cases.
https://i.pinimg.com/originals/8b/4a/6f/8b4a6fd7b8d65711eed41850a194284e.jpg
A sound meter and some white noise played into the device should be all needed to determine the effects at least in the typical human audio range up to 20khz.
I would think some using it might want to consider an active crossover for it to blend it in properly for best/flat response similar to adding a subwoofer.
As mentioned above, another consideration is more high frequencies will always result in a smaller soundstage (higher frequencies are more directional) unless the device artificially disperses the high frequencies in some way. Whether that is a good or bad thing also will vary case by case.
Focal speakers tend to deliver more "air" than many in my experience, so would tend to think a supertweet with Focals in general is not the best pairing. Maybe still perhaps for some of us with older ears who are most likely to benefit from a 10Khz+ frequency boost?
A lot of potentially fatiguing noise can occur naturally in that range so that is something worth considering case by case....how much better sound versus noise as a result.
Also if the device has response down to 10khz then it would seem best applied in systems that can use a boost in that upper range which with music is where "air" occurs. The result would likely be a sense of more "air" and perhaps a tad more "pierce" in that case which many might find desirable in some cases.
https://i.pinimg.com/originals/8b/4a/6f/8b4a6fd7b8d65711eed41850a194284e.jpg
A sound meter and some white noise played into the device should be all needed to determine the effects at least in the typical human audio range up to 20khz.
I would think some using it might want to consider an active crossover for it to blend it in properly for best/flat response similar to adding a subwoofer.
As mentioned above, another consideration is more high frequencies will always result in a smaller soundstage (higher frequencies are more directional) unless the device artificially disperses the high frequencies in some way. Whether that is a good or bad thing also will vary case by case.
Focal speakers tend to deliver more "air" than many in my experience, so would tend to think a supertweet with Focals in general is not the best pairing. Maybe still perhaps for some of us with older ears who are most likely to benefit from a 10Khz+ frequency boost?