My Pro tests

onlyoneme

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Oct 20, 2022
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I've got my unit, so time for testing.
First batch are tests when connected to RME ADI-2.
In REW FFT tests there is nothing to say - performance over coax and toslink is the same and equal to Mini. My measurements include sine 0 dBFS, j-test, SMPTE and sweeps, all in 48kHz and 96 kHz.
 
Chromecast measurements look quite good if peaks are below 0 dBFS.

sine -0.1 dBFS:

1672143642844.png

sine 0 dbFS:

1672143718621.png


As a result Pro cannot pass RME bit-perfect test when chromecast is used.
 
thank you
no surprise...
;-)
you can compare mini and pro analog output?
1k -12k, imd ,and multitone like ap32?

; -)
 
Considering time domain it's possible to get bit-perfect stream when connected to the RME ADI-2, with an exception for mentioned fade-in effect at the very beginning.

It's not possible when chromecast is being used. Some samples are removed:

1672146078950.png
1672146114863.png
 
DeltaWave calculates PK metric quite low when comparing a stream casted over chromecast to the original one:

PK Metric (step=400ms, overlap=50%):
RMS=-63,2dBFS
Median=-109,7
Max=-45,3

99%: -47,54
75%: -107,91
50%: -109,69
25%: -111,8
1%: -∞

And for bit-perfect comparison:

Files are NOT a bit-perfect match (match=9,33%) at 16 bits
Files are NOT a bit-perfect match (match=0,04%) at 24 bits
Files match @ 50,044% when reduced to 13,22 bits

Test sample was 6 s long.
 
Measurement on miniDSP Flex have shown some differences between Mini and Pro. Flex doesn't have a sophisticated jitter suppression over spdif nor reclocking, but uses ASRC instead to hadle a jitter. All below in digital domain only.

Mini j-test:
1672155998229.png

Pro j-test:
1672156023262.png

Mini sine:
1672156060443.png

Pro sine:
1672156087551.png

Drawings look cleaner for Pro.
 
So, with EQ turned off, the Pro will contribute nothing audible. Great.

Now I hope they get Roon support working before Amir tests it, lol.
 
Performance in the analog domain looks quite similar for Mini and Pro, with a small advantage of Pro, again especially in SMPTE test. Frankly speaking it's a very rough comparison as performance of AD conversion of Flex itself is far from perfect.

Mini:
1672164952856.png
1672164971365.png

Pro:
1672165038583.png
1672165058166.png

All tests above with really cheap RCA cables and devices powered by strong power bank.
 
thank you..
on the analog it is good to observe left and right...
in any case on certain mini the differences can be significant..

the pro indeed seems a bit cleaner...
at least so modest..go the right way
;-)
 
I've repeated chromecast tests with Hi-Fi Cast instead of LMS with cast bridge. This time no distortions at 0 dBFS, but still not bit-perfect. All data captured with cheap spdif recorder Hifime S2 Digi.

Chromecast 48 kHz/24 bit:

1672171568537.png

DLNA 48 kHz/24 bit:
1672171625355.png
 
Results of comparison in DeltaWave were much better then before:

PK Metric (step=400ms, overlap=50%):
RMS=-109,9dBFS
Median=-110,6
Max=-105,3

99%: -105,37
75%: -108,56
50%: -110,59
25%: -111,72
1%: -116,62

And for bit-perfect comparison:

Files are NOT a bit-perfect match (match=85,16%) at 16 bits
Files are NOT a bit-perfect match (match=1,14%) at 24 bits
Files match @ 50,002% when reduced to 18,16 bits

Test sample was the same as before.


Hi-Fi Cast can obviously deliver gapless playback over chromecast.
 
DeltaWave calculates PK metric quite low when comparing a stream casted over chromecast to the original one:

PK Metric (step=400ms, overlap=50%):
RMS=-63,2dBFS
Median=-109,7
Max=-45,3

99%: -47,54
75%: -107,91
50%: -109,69
25%: -111,8
1%: -∞

And for bit-perfect comparison:

Files are NOT a bit-perfect match (match=9,33%) at 16 bits
Files are NOT a bit-perfect match (match=0,04%) at 24 bits
Files match @ 50,044% when reduced to 13,22 bits

Test sample was 6 s long.
but with dlna ..what is the result with deltawave?
;-)
(
to specify the reason for the precaution of observing l and r in analog..
from memory:
I typically had this kind of thd+n value on the left..and the same kind of value you see on your pro measurement in "r" and
with a fairly significant difference in level between the two channels ..

to be honest, I expect to find something a little cleaner and above all more balanced on the pro.
to have..
(this explains why I was again pointing out the idea of mono and balance)
;-)
)
 
Last edited:
but with dlna ..what is the result with deltawave?
;-)
(
to specify the reason for the precaution of observing l and r in analog..
from memory:
I typically had this kind of thd+n value on the left..and the same kind of value you see on your pro measurement in "r" and
with a fairly significant difference in level between the two channels ..

to be honest, I expect to find something a little cleaner and above all more balanced on the pro.
to have..
(this explains why I was again pointing out the idea of mono and balance)
;-)
)
For DLNA it's a bit perfect transfer.
 
This is deal breaker as I thought chromecast is bit perfect.
Well, maybe it's possible but I cannot achieve it.

I've repeated some tests over chromecast. My conclusion is that for 48 kHz sample rate the audio stream seems to be very close to the original even for 0 dBFS peaks, as it can be seen on the last graphs. Things look worse for 96 kHz unfortunately as you see that when I've used LMS.
When I've used Hi-Fi Cast with 96 kHz I got the same performance in FFT as with LMS, so casting application didn't matter here.
 
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