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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
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
483 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.
sandthemall
544 posts
 
15khz! That’s crazy! Now, if you don’t mind, I’m gonna listen to my records. Good stuff…

tonywinga's avatar
tonywinga OP
844 posts
 
This is all not so straight forward.  I streamed music, both 16 bit and 24 bit and I see frequenciies out to 20kHz.  Then I went back to the test disc on Qobuz titled, "Audio Line-up Test Tones".  Some tracks cut off at 15kHz such as the test tones at specific frequencies, frequency sweeps  and some pink noise tracks but some tracks go out to 20 kHz such as the white noise tracks and other pink noise tracks at -10dB for example.  Really strange is that the specific 18 kHz test tone track shows no response for me while my own test CD shows a response at that frequency just fine.
My conclusion is Qobuz is streaming the full bandwidth and I happened to stumble across a test disc in their library with some foibles.  
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