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Cheapo HDMI Audio Extractor - some measurements

Lalaland

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Good afternoon all

So I got this cheap HDMI 7.1 audio extractor (aprox. 50$) off ebay or aliexpress (can't quite remember). Usually these kind of products either miss a bunch of specs or stated specs are a blatant lie. So I decided to try some measuring myself. Be warned though - I am no expert, more like a total noob.

My intended use for this thing was a cheap gateway into multiway active speaker building. Started out with my Yamaha AVR's HDMI input and EQAPO, but never got comfortable with the idea of the AVR internal DSP and circuits messing with things, so I got this audio extractor. Still using the AVR, but with analog multi channel inputs.

Mostly I was interrested in voltage on max output and noise floor - no high expectations.

Here it is:

HDMI box f.PNG
HDMI box r.PNG


Running REW with Java drivers (EXCL?) as Asio wont work. Capture device is Behringer UMC204HD TRS insert to bypass preamps.

Noise floor with no connection on input(forgot to close settings window, so there is a little spike at 18kHz not seen):
Behringer UMC204HD no input noise floor.jpg

HDMI extractor connected, no signal:
HDMI extractor no input noise floor.jpg
 
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Lalaland

Lalaland

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Calibration sweep:
HDMI extractor cal sweep.jpg

1kHz sine:
HDMI extractor sine 1kHz.jpg

Scope reading at 0dBFs (UMC204 disconnected, as it clips at this level):
Scope full output.PNG


So that's what I got this far. Please let me know if you have suggestions, comments or advice
 
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Lalaland

Lalaland

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Opened the case to have a look, so if anyone should be interrested the DAC chips are 4354-CSZ, main chip EP92A3E.
I'm guessing my measurments are not too useful/valid, but PCB had a manufacturers name, so found the specs on the webpage

Specs.PNG
Inside.PNG
 

Rja4000

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Interesting.

Is REW set for 24 bits ?
Could you try and measure the SPDIF out, by any chance ?
 
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TonyJZX

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Looks like better results from your basic tests than most Denon or Marantz AVRs.

'high quality thru simplicity'

i have the cousin to this... basically a $20 four port hdmi switcher that has optical out... works fine... uses the same style sheet case print and colours.

about the dac on board:

The CS4354 is a 24-bit, 192 kHz stereo audio digital/analog converter (DAC) with a 101 dB dynamic range and on-chip 2 VRMS line driver working from a single 5 V power supply. Based on a charge-pump architecture, this IC outputs a 2 VRMS voltage without the need for a high voltage regulator and features a ground-centered output architecture removing the need for external DC blocking capacitors and any pop prevention circuit. The results is a reduction in external component and valuable.

should be like a few dollars in the thousands

if you load in "HDMI 7.1 audio extractor" in your local ebay you should get this

to my thinking this is a dumb 'decoder'? the diagrams show you just plug it into an 7.1 channel input surround receiver and it just goes?
 
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Lalaland

Lalaland

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Interesting.

Is REW set for 24 bits ?
Could you try and measure the SPDIF out, by any chance ?
REW set for Java drivers - WASAPI exclusive mode. I'm just learning about this feature. It is indeed working as 24-bit, but I'm not sure there is a function to monitor data-flow for output. Only input is shown as actual data used
REW input data.PNG


I guess I could try out some measurements of the SPDIF out, but I have to "borrow" my Minidsp 2x4HD from my living room setup, so I'll try to find time soon.
 
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Lalaland

Lalaland

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'high quality thru simplicity'

i have the cousin to this... basically a $20 four port hdmi switcher that has optical out... works fine... uses the same style sheet case print and colours.

about the dac on board:

The CS4354 is a 24-bit, 192 kHz stereo audio digital/analog converter (DAC) with a 101 dB dynamic range and on-chip 2 VRMS line driver working from a single 5 V power supply. Based on a charge-pump architecture, this IC outputs a 2 VRMS voltage without the need for a high voltage regulator and features a ground-centered output architecture removing the need for external DC blocking capacitors and any pop prevention circuit. The results is a reduction in external component and valuable.

should be like a few dollars in the thousands

if you load in "HDMI 7.1 audio extractor" in your local ebay you should get this

to my thinking this is a dumb 'decoder'? the diagrams show you just plug it into an 7.1 channel input surround receiver and it just goes?
Seems to me like HDMI ports are just "pass-trough" or what one would call it, it just lets you tap into the audio channels. I have not tried out the HDMI out as I'm only using it as a multichannel output device from pc based dsp experiments. I did read the data-sheet on the CS4354 DAC, and to me it does not seem to be implemented as suggested by manufacturer. It might be room for improvements, but I'm not sure and probably not worth the effort
 
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Lalaland

Lalaland

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Looks like better results from your basic tests than most Denon or Marantz AVRs.
I have both my Yamaha and a Denon AVR so could probably do some tests to compare, but I would need some pointers on how to set it up for the tests to be valid
 

Biblob

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Not that bad first impressions. Could you measure on other outputs? Also, I'm curious what the output voltage is.
 

Rja4000

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I get similar results while looping back on my Blackmagic Design ATEM Mini Extreme ISO
(PC => BMD => PC)
Full numeric path (but 16 bits)

So I guess I'd get the same on the HDMI output or from an HDMI input.

BMD ATEM Min Extreme ISO - HDMI Loopback.png
 
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Lalaland

Lalaland

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I get similar results while looping back on my Blackmagic Design ATEM Mini Extreme ISO
(PC => BMD => PC)
Full numeric path (but 16 bits)

So I guess I'd get the same on the HDMI output or from an HDMI input.

View attachment 240240
Looks cleaner to me. What kind of software is your screenshot from? Looks interesting
 

Rja4000

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Looks cleaner to me. What kind of software is your screenshot from? Looks interesting
Well, as said, that's pure digital path.

The ATEM is basically an HDMI mixer, which may also mix (stereo) audio signals from HDMI (and to HDMI).

The software is Virtins Multi Instrument 3.9.
I created the dashboard.
You may find explanations in this thread.

There are several posts explaining the build of the dashboard. And the dashboard file itself is attached to (one of) the last post(s).

Here we are in pure digital, so the APU is not used, of course.
 
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Lalaland

Lalaland

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Well, as said, that's pure digital path.

The ATEM is basically an HDMI mixer, which may also mix (stereo) audio signals from HDMI (and to HDMI).

The software is Virtins Multi Instrument 3.9.
I created the dashboard.
You may find explanations in this thread.

There are several posts explaining the build of the dashboard. And the dashboard file itself is attached to (one of) the last post(s).

Here we are in pure digital, so the APU is not used, of course.
Thank you for posting this, your link is much apreciated. I don't think I will be at this level anytime soon, but I will read that entire thread to learn more about this topic.
 
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Lalaland

Lalaland

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Not that bad first impressions. Could you measure on other outputs? Also, I'm curious what the output voltage is.
All outputs measures the same in my setup. Output voltage is 2Vrms on 0dBFs
 

Rja4000

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I get similar results while looping back on my Blackmagic Design ATEM Mini Extreme ISO
(PC => BMD => PC)
Full numeric path (but 16 bits)

So I guess I'd get the same on the HDMI output or from an HDMI input.

One more measurement of the BlackMagic Design ATEM Mini Extreme ISO

Now with PC > BMD > BMD Headphones out > RME AD-2 Pro fs R ANA In
So, in that case, that's the DAC of the BMD in action.

PC Digital level set to -0.4dBFS (there is a very clear saturation at 0dBFS)
BMD Output Level is around 11.6dBu (around 3V)

BMD ATEM Min Extreme ISO - HDMI Loopback Headphones out_crop.png



Same, but with a load of 300 Ohm

BMD ATEM Min Extreme ISO - HDMI Loopback Headphones out_crop 300 Ohm.png



So your cheap device at 0.011% THD+N (79dB SINAD) is actually not that bad.
 
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Lalaland

Lalaland

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Did some more tests. Optical out looped back into minidsp 2x4HD

HDMI extractor optical out sine 1kHz.jpg

Is this realistic, with that low noise floor? REW settings are Exclusive mode. Monitor says 32 bit in 32 bit out, but output is not over 24 bit for this device.
And another RCA out, but multitone. I don't know, it doesn't look too good in my eyes

HDMI extractor multi tone.jpg
 
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Rja4000

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Did some more tests. Optical out looped back into minidsp 2x4HD

View attachment 240485
Is this realistic, with that low noise floor? REW settings are Exclusive mode. Monitor says 32 bit in 32 bit out, but output is not over 24 bit for this device.
And another RCA out, but multitone. I don't know, it doesn't look too good in my eyes

View attachment 240486

That's 125dB SINAD in pure digital.
A bit shy of the 24 bits (more like 21 bits), but for that price, that's pretty good. :)
 
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