Frequency response while streaming stops at 15kHz- did I miss something in the fine print?


I am streaming with Qobuz.  It sounds great playing both CD quality and hi-rez music.  So what's the trouble?  While working to get the bass response in my room just right I found test tracks on Qobuz.  This was very handy as I played 30-60 Hz test tones over and over.  So when I was done with that I streamed a pink noise track and pulled up the FFT analyzer app on my iPhone.  Surprisingly, I see the trace drop straight down to 0 dB above 15 kHz.  I streamed some test tones and confirmed that above 15 kHz nothing is happening at the speakers.  In my old and decrepit state I can no longer hear above 15 kHz so I am relying on the app.  In a panic that something is wrong with my speakers I pull out my vinyl test record.  I have a nice, pretty flat frequency response from 20-20 kHz showing on the FFT app.  I put in a test CD and again show a good 20-20k.  Lastly, I ripped the test CD onto my server and again had a good 20-20k response.  So why did I not know about the limited bandwidth while streaming?  Is it just me?  It is an abrupt cutoff above 15 kHz while streaming.  What's going on?
128x128tonywinga
My guess would be something in your streaming setup is filtering above that frequency.   Could  be a setting somewhere.  
While you may not hear above 15khz, the overall effect on the music can be significant. After decades of working on my system, and own Heils and other planar speakers I realized that the real high frequency has a profound impact on the overall sound quality. I have not fiddled with measuring up that high. But a cut off sounds artificial. I’ll be interested to hear more about this.
Allan Silverman one of the recording industries best.
https://youtu.be/EiRMYoqU3ys?t=575

So Digital is a quest for loudness. Utter garbage. 

I did the same experiment but used test tones played back from my PC and the response seemed to stop at 15 to 16KHz.  I suspect the reason was not my test tones or my system, but a limitation of the iPhone microphone.