Super tweeters, are they worthwile?


Hello guys
I've been reading some infomation on the web about super tweeters and I've got curious.
First I didnt believe in subwoofers, I thought the would only add bass quantity to my system and then I got convinced and I tried one. Well, I couldnt believe how much it improved the 3D image, making it rock solid and so real. And I thought soundstage was mostly the tweeters job. 
Now I read some guys swear that super tweeters can also improve the soundstage, 3D image and bass!!  Well, If a sub can improve the mid and high frequencies, I think I can believe super tweeters could improve bass. 
First, I would like to now your experience with super tweeters, please only the ones who actually tried them. 
Second, if I listen all of my music streaming Tidal hifi (44.1 kHz), does this sample rate have ultrasonic infomation for the super tweeters to play? If not, does software or hardware (DAC) upsampling delivery it? 
Finally, wich super tweeters would you recomend under 1k the pair? I mean, ready to plug and play. I dont have the expertise, nor the time and patience to build crossovers, etc.
Just to mention, I live in a country where I dont have the chance to borrow them from a dealer with a trial period. I have to buy everything blindly. 
Thanks!! 

plga
Op, you're correct in wondering if a cd quality recording has any information at that high a frequency.  It doesn't. Perhaps a wider dispersion tweeter would be more beneficial for you? I like the idea of upgrading your dac as well.
So tidying up is the reason, thank you. I have also heard about the value of "moving air" even if its  above the audible level. The dogs may love it but somehow I think my money has to go into what I still can here. 
Show me a speaker to A/B with to prove your point and I will concede.
Signed, Missouri.
plga OP

I use a pair of these passively (18db) crossed over from 10khz up on my Martin Logan Monolith III's, even though the ML's have the latest panels and have incredible highs, the Plasma tweeters are so much better, the highs dance in front of you like fireflies, you swear you can reach out and grab them.
  https://www.ebay.com.au/itm/Magnat-Plasma-MP-02-ion-tweeter-massless-air-plasma-speaker-Plasmahochtoner/272894087984?hash=item3f89c15330:g:V5sAAOSwCJxZ6PXy&frcectupt=true

Cheers George  
So tidying up is the reason, thank you. I have also heard about the value of "moving air" even if its above the audible level. The dogs may love it but somehow I think my money has to go into what I still can here.
Show me a speaker to A/B with to prove your point and I will concede.
Signed, Missouri.
....Since the dogs are not paying for any of this stuff who cares what they hear :-)

As theTownsend Super Tweeters has an ’Off’ switch at the back you can do the A/B comparison on your own speaker easily.
Back in the day, when KEF Concertos were a big deal, I built a pair of KEF Transmission Lines around 1978 which had a super tweeter as the only hardware difference between the two.

Having said that, there was a lot of difference in the cabinets both internally and externally and the TLs were designed with the super tweeter in mind.

The Transmission Lines used Rogers speakers that I imported from the UK.

They did sound a lot different to my friends Concertos. Bassier and certainly a bit more up top.

I suspect some of the difference came down to the cabinets.
Are you planning on pulling out your tweeters and replacing them with the supers? I think they are meant to augment existing tweeters and you will probably end up losing more of the "lower" high frequencies if that makes sense. I’m sure you added the subs without removing the existing bass speakers, right?

In my experience, I find that I can't agree with the remarks about the frequencies above 10Kh not making any audible difference.

Just as the subs added something extra, the super tweeters probably will to. It’s all in there in the recordings and each addition that enables you to hear more of it helps to make it sound more balanced and complete from top to bottom.
Enjoy the journey.