Can you hear a difference between dac+amp path with 92dB vs. 78dB SINAD? (test)

[solderdude]

Who normally listens to music with their ear right next to the tweeter?

I often have my ears just right next to a driver (not tweeter)

To mimic the 'easy to hear the difference' method I would have to crank up the volume right to 120dB average SPL and high-pass shelve at a few a few kHz and then only listen to a the system without much or any signal.

So in reality it is not an audible difference but as one can see a difference in noise level of the system at a certain SPL that difference will become audible.
There is nothing strange about that.

Listening at 85dB average at 3m turns into the equivalent of around 120dB at 5cm from a tweeter.
So increasing the gain by 35dB at a quiet passage should make the difference audible.

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[pma]

So increasing the gain by 35dB at a quiet passage should make the difference audible.

I would like to see the passage of the test files, dacamp_test1.flac and dacamp_test2.flac, where the 35dB gain makes audible difference in noise. Excluding first 2s, that were generated as a "digital silence". I would like to see the real thing, instead of theoretical debate. I am just one ear.

 

[DanielT]

Can you hear a difference between dac+amp path with 92dB vs. 78dB SINAD?

Quite a lot has been said here about “audibility” of SINAD, or existing/non-existing sound differences between amplifiers or DACs. Quite often we forget to evaluate SINAD of the whole audio chain consisting of a DAC, power amplifier, and eventually a preamplifier. It is the gain structure of the whole chain and individual noises of the components used that usually define the resulting SINAD of the complete audio chain, in case we have no ground loop issues. The gain structure and noise is a key, as will be explained.

Let's investigate 2 complete audio chains, one of them consisting of a DAC1, analog preamplifier and a power amplifier, the other one just from a DAC2 with digital volume control and the same power amplifier.

Chain1: Topping D10s DAC, OPFET preamplifier with balanced output (my design), Hypex NC252MP power amplifier.

Chain2: iConnectAudio4 DAC with digital volume control, Hypex NC252MP power amplifier.

Output signal is recorded from NC252MP outputs. Output voltage from NC252MP was 0 – 4V, to match common listening level at home listening conditions. NC252MP has 26dB gain (20x), so the DAC or preamp output would be only 0 – 200mV, about 20dB below the DAC full scale output.
-------------------

Chain1 with Topping D10s and the preamp shows THD = 0.002%, THD+N = 0.0025% and SINAD = 92.04dB at 4Vrms measured at the NC252MP output.

View attachment 328781
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Chain2 with iConnectAudio4 shows THD = 0.00098%, THD+N = 0.013% and SINAD = 77.72dB at 4Vrms measured at NC252MP output. SINAD is now of 14dB worse, as a result of higher permanent voltage noise at the output of the iConnectAudio4 DAC analog output. Though there is one componet in the chain missing (the preamp), SINAD is worse due to higher noise of the DAC analog output.
View attachment 328782
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THD vs. frequency comparison

View attachment 328830

The same track was recorded through Chain1 and Chain2 and you can download these 2 files from

https://pmacura.cz/dacamp_test.zip

The files are in 96/24 flac format. You can try if you hear a difference and if you do, please let us know and also post a foobar2000 ABX protocol here.

The files were also compared by Paul's @pkane excellent Deltawe software and these are the results:

View attachment 328783 View attachment 328784

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And this is my ABX report

foo_abx 2.1 report
foobar2000 v2.0
2023-11-23 15:29:47

File A: dacamp_test1.flac
SHA1: d18e80d55835f5f2db9e29c2246e9bb67e5e36e9
File B: dacamp_test2.flac
SHA1: fbab6bd34063f58dfb5962479bbe62c88810d35e

Output:
ASIO : Topping USB Audio Device
Crossfading: NO

15:29:47 : Test started.
15:31:05 : 00/01
15:31:25 : 00/02
15:31:38 : 00/03
15:31:54 : 01/04
15:32:24 : 01/05
15:32:40 : 02/06
15:33:07 : 02/07
15:33:18 : 03/08
15:33:47 : 03/09
15:34:05 : 04/10
15:34:25 : 04/11
15:34:46 : 05/12
15:35:05 : 05/13
15:35:33 : 05/14
15:35:55 : 06/15
15:36:16 : 07/16
15:36:16 : Test finished.

 ----------
Total: 7/16
p-value: 0.7728 (77.28%)

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4f3a6e8052276d96850c23e7c0f8ee297ffa2ab0

______________________________________
Edit
Original file

I am posting the original file as well:

https://pmacura.cz/dacamp_orig.zip

Please feel free to use it in your ABX comparisons as well.

Good initiative PMA! But 92dB vs. 78dB ..hm... Can't you get down to 92dB vs 68dB or 58dB. Because I say like Thomas:

Nice to see these ABXs trials. However, I already know this is below my threshold of audibility and there will be a null result.

Same with me.

 

[solderdude]

Good initiative PMA! But 92dB vs. 78dB ..hm... Can't you get down to 92dB vs 68dB or 58dB. Because I say like Thomas:

Same with me.

use the programm distort or use an audio editor to add noise at those levels or even use both.
You can generate your own test files.

 

[DanielT]

use the programm distort or use an audio editor to add noise at those levels or even use both.
You can generate your own test files.

I came to think of when it becomes audible. At least it MUST have been so with the HiFi I had in my younger teenage years. Mostly bad to mediocre stuff. Tuner and then FM radio recorded via cassette recorder then played back on ...well some type of DIY speaker I borrowed from my father.
I can guess that there was upwards towards 10% distortion in that solution.
Anyway, it wasn't something I reflected on at the time It kind of just was what it was.

 

[restorer-john]

I just ran a 16 trial test. Thought I could hear differences, but clearly I couldn't. I might try again later without the fan blasting and a better pair of headphones.

 

[pma]

Thought I could hear differences, but clearly I couldn't.

That’s it. Very often. I am no exception .

 

[ctrl]

As expected, no chance of recognizing a difference. In the first attempt 6/10 in the second attempt 4/10 - so both recordings are interchangeable for me.

 

[Glaurung]

Greetings to all,
This is my first post on this forum. My two cents on this: you have a Spurious Free Dynamic Range (SFDR) pretty good (>90dB) for both systems despite the relatively high SINAD difference. Will be very difficult to detect an audible difference on the attached files. Maybe if you record these at -60dBFS the SINAD difference will come into place.

 

[pma]

Greetings to all,
This is my first post on this forum. My two cents on this: you have a Spurious Free Dynamic Range (SFDR) pretty good (>90dB) for both systems despite the relatively high SINAD difference. Will be very difficult to detect an audible difference on the attached files. Maybe if you record these at -60dBFS the SINAD difference will come into place.

Hi, welcome to ASR! You may be right about recording at -60dBFS, but, I am sure that in such case people would turn volume up to maximum to hear the difference. Standard listening conditions would be violated.

 

[DanielT]

Greetings to all,
This is my first post on this forum. My two cents on this: you have a Spurious Free Dynamic Range (SFDR) pretty good (>90dB) for both systems despite the relatively high SINAD difference. Will be very difficult to detect an audible difference on the attached files. Maybe if you record these at -60dBFS the SINAD difference will come into place.

I say as PMA: Hi, welcome to ASR!

The challenge is very much to have speakers or headphones with really low distortion and low noise. Because everything is added in the chain:

How do you sum up distortion in the sound chain?

That's the question. Anyone have the answer? It's not as simple as just a plus, is it? For example 0,03% + 0,3% = 0,33%? Edit: After a bit of googling that it seems to be about some kind of Root Mean Square calculation ..Or...

audiosciencereview.com

Having said that even with ULTRA low distortion speakers/ headphones to detect 92dB vs. 78dB I think is really hard. I don't know because I don't have any such speakers or headphones. Regarding really low distorting speakers, I'm thinking of, for example, electrostatic ones. That type of speaker can have super low distortion.

 

[Glaurung]

Hi, welcome to ASR! You may be right about recording at -60dBFS, but, I am sure that in such case people would turn volume up to maximum to hear the difference. Standard listening conditions would be violated.

Thank you! Definitely they will push the level up. But when you do this the difference between the two records will become obvious.
I run a simple experiment which I encourage everyone to do. Just generate a simple tone of a frequency between 1kHz and maybe 5kHz. Set the generator to 0dBFS and don't forget to set the volume knob to the minimum! Increase the volume until you can hear the tone at an acceptable loud level. Now don't touch the volume knob anymore and play with the generator level (go down to -100dBFS). Stop when you cannot hear the tone. In my case and for my system this level was at -94dBFS. Can't go lower. This is my usable dynamic range (ears+DAC/Amp+Headphones) in the "lab conditions". For a recorded material this dynamic range will be worst (distortions of different kind, noise and so on). For my particular case, a system with a SFDR of 90dB is a competent one and I will not be able to detect any difference if I compare this with a system that has a greater SFDM. Things will change if I redo the test with a reference level of -60dBFS. In this case I will start to notice the difference as I will push the volume up to compensate for the steep decrease in the level. All artifacts introduced by the system will show up quickly.
P.S. The test is more difficult to run that it may looks. Ambient noise is a big pain once you go to very low levels.