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
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. 
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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.
I suspect it more that they save 20% of streaming/download space by not letting it go out to 20k regardless if there's info on it or not.

Cheers George
I checked my Roon settings.  The only thing I find related to frequency response is a low pass filter which is set at 30 kHz.  I don't think that is the issue.  The speakers go the full 20 kHz when playing back a FLAC version of my CD test disk loaded on the music server HDD.  The iPhone mic picks up 20 kHz no problem as I saw both from the CD test disc and my vinyl test record.
The only thing I find related to frequency response is a low pass filter which is set at 30 kHz
Depends what order it is and how many db down at 30k it already is.

Cheers George