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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
campaigner8
11 posts
 
All you need to know about quality streaming. Courtesy of Bryston. Beware; Have a fat wallet if you want the best in the industry. Between approximately $4000 and $12,000 to stream and play your high resolution music at its best. https://bryston.com/digital-audio/
georgehifi's avatar
georgehifi
10,312 posts
 
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
tonywinga's avatar
tonywinga OP
844 posts
 
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.
georgehifi's avatar
georgehifi
10,312 posts
 
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
p05129
482 posts
 
Nonoise - you use a mediocre system for your streaming test (speakers with a built in dac and using usb probably using iTunes too) and you think this is a good representation of a good streaming system? I’ll take streaming/playing ripped songs over using a CD player or vinyl.
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