E1DA 9038D performance according to df-metric

[solderdude]

It would be interesting to listen to the nulls which are amplified with the same gain.
apples vs apples

 

[Serge Smirnoff]

It would be interesting to listen to the nulls which are amplified with the same gain.
apples vs apples

+30dB applied to both NULLs

 

[pkane]

It would be interesting to listen to the nulls which are amplified with the same gain.
apples vs apples

Null signal audibility is interesting, but not always representative of the real audible differences between two devices due to various psychoacoustic effects. For example, level and frequency masking.

 

[solderdude]

Yep, but at least you can hear if the null does not sound 'distorted' in sound. If the distortion sounds 'nice' at least you know the change that is there is not going to be unpleasant sounding.

 

[solderdude]

+30dB applied to both NULLs

That's quite a substantial difference now.
It would appear as though the 9038 changes the sound a lot, hence the poor results.
The issue, however, seems to be phase only and not magnitude. This means that the substantial changes you hear are phase differences only and they appear to be gradual phase shifts so not of audible concern.

It would be interesting if someone measured the phase difference to quantify it and the second question (to @IVX ) would be where that would come from.
Even when it is not of any audible concern.

 

[IVX]

solderdude, 9038D has AC coupled output with HPF around 5Hz@-3db 1st order, probably, well-known "phase distortions" are detected which have every real HPF/LPF.

 

[pma]

Seems like another nitpicking about inaudible pseudo-issue.

 

[MaxwellsEq]

solderdude, 9038D has AC coupled output with HPF around 5Hz@-3db 1st order, probably, well-known "phase distortions" are detected which have every real HPF/LPF.

This is the thing I find fascinating. Just from a stability / risk point of view, I've always considered AC coupling a a good idea. What's more, I've assumed DC coupling is audibly unnecessary, since most of us cannot experience sub 20Hz music at home!

But the df-metric (which is supposed to map well to subjective opinions), is poorer for AC coupled designs due to relatively gentle phase shifts in the audible frequency range. Have we been missing something?

 

[solderdude]

Yep, but my question (to IVX) was what could cause the phase difference as it seems to be a high pass but was unsure if this was by design (output capacitor) and it seems it was just that.

Obviously the generated numbers are negatively affected giving the 9038 an undeserved thumbs down.
Of course Serge also noted it was only a phase thing and not amplitude thing.

Nulling works fine for amplitude differences but as soon as phase shifts come into play (bottom and upper part of the audible range) it would need to be characterized and the phase part of the null should be masked or compensated for before the 'numbers' are generated if the goal is to asses audibility issues.

This should be possible as the source is known, a sweep can be included for phase characterization and the ADC part can also be fully characterized.
Then we only have clock drift and thought Paul addressed that part successfully.

 

[IVX]

Yep, but my question (to IVX) was what could cause the phase difference as it seems to be a high pass but was unsure if this was by design (output capacitor) and it seems it was just that.

Obviously the generated numbers are negatively affected giving the 9038 an undeserved thumbs down.
Of course Serge also noted it was only a phase thing and not amplitude thing.

Nulling works fine for amplitude differences but as soon as phase shifts come into play (bottom and upper part of the audible range) it would need to be characterized and the phase part of the null should be masked or compensated for before the 'numbers' are generated if the goal is to asses audibility issues.

This should be possible as the source is known, a sweep can be included for phase characterization and the ADC part can also be fully characterized.
Then we only have clock drift and thought Paul addressed that part successfully.

exactly, and as I said on the first page of that topic:
1) the new method has to prove that it flawlessly includes a classic test set and adds new tests for a better characterization of the Sound Quality perception. I.e. not just another one but a better test.
2) get right to talk about the SQ
3) whatever
I am always jealous ICC(International Color Consortium kinda analog of AES but for eyes) approach because it's a lot more structured and systematic than the audio area.
ICC builds a new "human vision" model(CIECAM16 the latest one) every 10 years or so, and that is always like a Successive approximation, no any surprises only the model becomes closer and closer to our vision sense.

 

[half_dog]

This is the thing I find fascinating. Just from a stability / risk point of view, I've always considered AC coupling a a good idea. What's more, I've assumed DC coupling is audibly unnecessary, since most of us cannot experience sub 20Hz music at home!

But the df-metric (which is supposed to map well to subjective opinions), is poorer for AC coupled designs due to relatively gentle phase shifts in the audible frequency range. Have we been missing something?

I have to disagree. With most recents IEMs and some closed back headphones is not that difficult to hear infrasound (honestly, I think infrasound is an old "definition", there are some papers pointing that we can hear below 20Hz). But I agree musics seldom have material in this range.

 

[IVX]

yeah, 20Hz is easy but 15Hz is already only a wind in my ears, what about 5Hz?

 

[half_dog]

yeah, 20Hz is easy but 15Hz is already only a wind in my ears, what about 5Hz?

I'm completely fine with a HPF at 5Hz and consider it necessary .
About hearing 15Hz and lower for me it seems more a pulsing sensation (wind?) than a pure tone. I just think we should not say "we can not hear below 20Hz".

 

[IVX]

I guess it was said rather about the subwoofer than the headphones.

 

[MaxwellsEq]

I have to disagree. With most recents IEMs and some closed back headphones is not that difficult to hear infrasound (honestly, I think infrasound is an old "definition", there are some papers pointing that we can hear below 20Hz). But I agree musics seldom have material in this range.

I typed:

most of us cannot experience sub 20Hz music at home!

Which is why I typed "music". There's evidence we can experience pressure level changes sub 20Hz, and perhaps there's something coming out of IEMs that moves the eardrum, but I'm not convinced it's musical. At those frequencies most acoustic recordings include traffic rumble and air-conditioning etc.

 

[nagster]

Phase measurement of 9038D.
I don't have a Shanling device.

* All measurements were conducted with AP balanced input (200kohm) and no load.

 

[IVX]

nagster, looks real, and indeed the interpolation filter by default has some roll-off near 20k. You can change that to the Brickwall or so to get 22k -.5db or less.

 

[nagster]

nagster, looks real, and indeed the interpolation filter by default has some roll-off near 20k. You can change that to the Brickwall or so to get 22k -.5db or less.

I got it. thank you. I'll try downloading the app next time.

 

[solderdude]

Phase measurement of 9038D.

I don't have a Shanling device.

Is that loaded with 32ohm ?

 

[dualazmak]

I'm completely fine with a HPF at 5Hz and consider it necessary .
About hearing 15Hz and lower for me it seems more a pulsing sensation (wind?) than a pure tone. I just think we should not say "we can not hear below 20Hz".

Interesting, essentially agree with you; I do not have any objective measurement data though.

Just for your (our) reference, I recently shared this post on my project thread;
- Reproduction and listening/hearing/feeling sensations to 16 Hz (organ) sound with my DSP-based multichannel multi-SP-driver multi-amplifier fully active stereo audio system having big-heavy active L&R sub-woofers: #782
Where I wrote;
....
One another critical aspect of 16 Hz sound would be that we "hear" and "feel" such low Fq sound not only by our ears but also (more importantly/significantly) with our whole body receiving the sound-pressure (just as if receiving sharp pulses of vigorous transient storm windshear).

Consequently, the description/presentation/sharing of my (our) listening sensations/experiences to 16 Hz sound inevitably becomes mainly rather subjective expressions, with only a little bit of objective data and/or spec representation.
....