Working with some people from the hearing aid industry (real growth in audio business there) I learned that there is some really solid evidence that people fill in the missing parts at a pretty low level in the processing. This is from measurements using MRI /PET of musicians with hearing loss. The missing parts in music are replaced internally by the musician even though the person could not hear them. I'll try to get some published references to this. This is related and may be interesting but is not what I'm looking for: http://brain.oxfordjournals.org/content/123/10/2065.full.pdf I found a number of other interesting references on hearing while looking.
May I point out what this thread is about !!!
We are now having a conversation that has been had many times and can be had anytime and will probably be repeated ac nauseam....
But that is not what this thread is about:
IT IS ABOUT GETTING OUT YOUR SOLDERING IRON.
The rest is essentially just noise, if you don't just do that FIRST !!!
Cheers, Joe
.
We are now having a conversation that has been had many times and can be had anytime and will probably be repeated ac nauseam....
But that is not what this thread is about:
IT IS ABOUT GETTING OUT YOUR SOLDERING IRON.
The rest is essentially just noise, if you don't just do that FIRST !!!
Cheers, Joe
.
This is because the brain 'knows' the structure of the piece, through previous exposure. The answer when assessing is to deliberately, mentally switch off from that "knowing", and register the playback as a sequence of sound textures having no special musical meaning - it's a type of defocusing, it reminds me of that fad some years ago, of books of specially printed patterns, which turned into 3D worlds when looked at the "right way". If you analytically tried to see something it never worked, you had 'to let go' in your mind to see the objects - and a similar sort of thing helps when listening to audio, for differences ...
People talk of "active" listening, concentrating on what you're hearing - this is when the gaps are likely to filled in, whether you think it's happening or not. "Passive" hearing - using the music like a background filler - stops this ...
I do wonder if "objective listening" is an oxymoron?
I don't think there is such a thing.
It like vision, you see what you focus on only - and it is a subjective decision what you focus on.
That decides it, yes "objective listening" is really a decision on the fly of "what should I listen to" - and as soon as you think that as the music starts (unless you enjoy listening to test tones?), then objectivity has gone AWOL.
Now I think I will measure my hamburger before I eat it... could end up eating it cold?
But seriously - whether we like it or not, with all its flaws and weaknesses, with pitfalls galore... do we honestly have any better... or maybe... we really have no choice but to listen, so we might as well enjoy it. 🙂
Cheers, Joe
.
Prestons, where the M7 and M5 meets up - here 90% of the time, so 0412-203382 me if you ever get down near here. Promise I can make it interesting if you come around (sorry if it makes me sound like I am a perv attracting a victim). 🙂
Cheers, Joe
There are so many ways to listen - the simplest test for me is as my current tag line says, if the SQ isn't a slam dunk, every time, then there's some 'problem', something to be sorted out.
I've heard audio replay do amazing stuff - for me, there are no limits as to how good it can get - if the user goes to enough effort in refining everything. The human hearing system can soak up an amazingly complex sound scape, and comfortably make sense of it all - if one doesn't make it too painful to do so!
Thanks for the invite, probably in a couple of weeks time ... 🙂
Cheers,
As I can remember, it was a discussion here maybe about hearing of ultrasonic frequencies...
Fully by chance, I got an quite small ultrasound device used to get rid of the small animals around (mouses, rats, and so on). Of course I had to check if it is working... Connected it to the main and pressed the start button. It was a very low audible (like white) noise signal out of the special speakers, at one meter distance. But in very short time I had to switch it off again, because I start to had a sort of pain in my ears. And I had that almost pain many minutes after this experience.
It may be enough power in such devices, and this one works in declared range of 24Khz to 45Khz.
I head never before the occasion to try/"hear" a ultrasound device...
So, I can confirm, after this by just chance experiment that it may be possible for human hearing to detect sounds quite much over the audible range... Of course, the power level of these sounds it may play a important role...
One may not be very aware about these sounds, but something it may happen with the human senses, and some reactions or interpretations it may come as a results of such very high frequencies sounds...
Fully by chance, I got an quite small ultrasound device used to get rid of the small animals around (mouses, rats, and so on). Of course I had to check if it is working... Connected it to the main and pressed the start button. It was a very low audible (like white) noise signal out of the special speakers, at one meter distance. But in very short time I had to switch it off again, because I start to had a sort of pain in my ears. And I had that almost pain many minutes after this experience.
It may be enough power in such devices, and this one works in declared range of 24Khz to 45Khz.
I head never before the occasion to try/"hear" a ultrasound device...
So, I can confirm, after this by just chance experiment that it may be possible for human hearing to detect sounds quite much over the audible range... Of course, the power level of these sounds it may play a important role...
One may not be very aware about these sounds, but something it may happen with the human senses, and some reactions or interpretations it may come as a results of such very high frequencies sounds...
Last edited:
Hi Coris
I don't think what we are experiencing is level dependent IMO, but I can quite believe the effect that consistent ultra-high frequencies can have on a person. For example, it is known that taking a square wave in the middle of the audio range and then filter above 20KHz, should not be heard, but is readily audible to many who can't even hear 15KHz sine waves and sometimes even lower than that.
Personally I believe the logical explanation is incomplete 'integration' of pulses coming out of delta-sigma DACs that has to be performed by an analog post-DAC filter, that the common practice of filtering is insufficient to reconstitute the analog signal and that this is audible.
Think about, we must not hear the pulses but only the density of those pulses.
This would be audible at all levels.
Cheers, Joe
I don't think what we are experiencing is level dependent IMO, but I can quite believe the effect that consistent ultra-high frequencies can have on a person. For example, it is known that taking a square wave in the middle of the audio range and then filter above 20KHz, should not be heard, but is readily audible to many who can't even hear 15KHz sine waves and sometimes even lower than that.
Personally I believe the logical explanation is incomplete 'integration' of pulses coming out of delta-sigma DACs that has to be performed by an analog post-DAC filter, that the common practice of filtering is insufficient to reconstitute the analog signal and that this is audible.
Think about, we must not hear the pulses but only the density of those pulses.
This would be audible at all levels.
Cheers, Joe
I am all too familiar with those devices - when you live in a 250-year-old canal house, you learn a lot about keeping rodents at bay. Some people who visit us hear them, some not, so I decided to measure the output. Despite their specs, those devices produce a fair bit of energy at frequencies below 20 kHz -probably the result of intermodulation products caused by rather non-linear drivers.
"It is known" usually equates to "I have once heard someone claim"....
The only studies I have seen that have "shown" the effect you have described have been thoroughly debunked. Studies like that often fail to take into account intermodulation products in the audible range.
What Coris is describing has nothing to do with DACs, delta-sigma or otherwise.
I understand the words, but not the sentence...
I can believe it - worked in one place and several guys were badly affected by a 19KHz sine wave and complained. They couldn't necessarily hear it, but they were quite able to pick it when it was on, yet they were told only early teenagers and very young children could hear it - but you didn't need to hear it to be affected. It is not what we hear that is important, it is what we perceive.
Cheers, Joe
Well, my previous described experiment have nothing to do with the DAC, and this subject I think is really OT.
I just wanted to point out and confirm by own experience that ultrasonic frequencies it may be detected by human hearing in one or another way. This kind of sound is definitely not audible, but a human can detect something in this area. As Julf state, some people can "hear" this, some not...
When about this subject, I`m quite convinced that the impact of the ultrasonic frequencies on the audible sounds is very well detected/heard by us. The interpretation of such impact it may differ from one to another, and that because the "subjective" aspects in all this.
But when about audio spectre, there are not only the ultrasonic frequencies involved... The infrasonic frequencies it have their important part in the total appreciation of sounds by humans.
Have someone ever wonder why it is used the bass instruments in music? Why the need to have such low frequencies besides other in a band, orchestra, etc?
Infra-sounds are of course not to be heard in any way, but are to be feel it with the whole body, or parts of it. To feel the infra sounds is a quite important for the defence system of bodies (human or animal). We are made to detect such events, to instinctual defend us against hazards.
The low/very low end of audio frequencies spectre it have its important role in receiving the musical "messages", f. ex....
All these abilities give to many of us some special ways to appreciate the audio world, music and so on. Detecting sounds over the standard audio spectre, give to the bodies the abilities to appreciate very fine details, harmonics, distortions, spacial distribution of sounds sources, directions, etc. Detecting in the very low end of the spectre, it make for many to just feel the music... And this it may be a quite special experience.
I just want to say that I`m personally a little bit frustrated when I have to use headphones to listen to my music. For me is definitely not the same as when I get the music out from speakers. It may be for sure the same for many others...
There is quite known that we do not know too much about ourselves possibilities and/or abilities...
When about this DAC filtering subject (to be back into the topic...), I must say that I`m quite disappointed about some or many`s scepticism in trying it this out (when is so simple to be done), and then express their opinions about...
I just wanted to point out and confirm by own experience that ultrasonic frequencies it may be detected by human hearing in one or another way. This kind of sound is definitely not audible, but a human can detect something in this area. As Julf state, some people can "hear" this, some not...
When about this subject, I`m quite convinced that the impact of the ultrasonic frequencies on the audible sounds is very well detected/heard by us. The interpretation of such impact it may differ from one to another, and that because the "subjective" aspects in all this.
But when about audio spectre, there are not only the ultrasonic frequencies involved... The infrasonic frequencies it have their important part in the total appreciation of sounds by humans.
Have someone ever wonder why it is used the bass instruments in music? Why the need to have such low frequencies besides other in a band, orchestra, etc?
Infra-sounds are of course not to be heard in any way, but are to be feel it with the whole body, or parts of it. To feel the infra sounds is a quite important for the defence system of bodies (human or animal). We are made to detect such events, to instinctual defend us against hazards.
The low/very low end of audio frequencies spectre it have its important role in receiving the musical "messages", f. ex....
All these abilities give to many of us some special ways to appreciate the audio world, music and so on. Detecting sounds over the standard audio spectre, give to the bodies the abilities to appreciate very fine details, harmonics, distortions, spacial distribution of sounds sources, directions, etc. Detecting in the very low end of the spectre, it make for many to just feel the music... And this it may be a quite special experience.
I just want to say that I`m personally a little bit frustrated when I have to use headphones to listen to my music. For me is definitely not the same as when I get the music out from speakers. It may be for sure the same for many others...
There is quite known that we do not know too much about ourselves possibilities and/or abilities...
When about this DAC filtering subject (to be back into the topic...), I must say that I`m quite disappointed about some or many`s scepticism in trying it this out (when is so simple to be done), and then express their opinions about...
But can' t that end up meaning "It is not what we hear that is important, it is what we think we hear"?
Absolutely.
And I just wanted to point out that your example only showed that the devices actually generate sound in the audible range (at least for some people).
Some people can hear up to 20 kHz, most can not. The ultrasonic rodent deterrent devices have significant energy *below* 20 kHz (but above 15 kHz).
There has been thousands of scientific studies showing that the human audible range ends around 20 kHz. There has been no verified ones showing any sort of hearing above 22 kHz, and anything above 18 kHz or so requires a lot of energy to be even vaguely audible.
Yes, and the effect of infrasonic frequencies is well researched and documented.
They would, if we could...
I had an ultrasonic mosquito repellent... Since the power supply in it did not have a smoothing capacitor, its output was ultrasonic, but with 100 Hz modulation. Extremely annoying.
Who thought that this thread it may be abandoned, it took wrong...😉😀
Well, I had in the last time the opportunity to take a closer look at this filtering trick, this time for ES9018 chip. BTW, it worked and it still work just fine for me on PCM1792.
In my system with ES9018, I use a post DAC signal processing without any filtering of the residual DAC HF noises. I have reduced their levels at under 100mV, for a useful audio signal of 12-16 Vpp, so is fine for me. My output on the L/R channels looks like in the pic 1
The probes are connected directly to the L/R channels output (no any audio signal). BTW, this residual HF noise is present only when the clock signal is active at the DAC clock pin.
I have connected 2x1n between the ES9018 differential output phases on its channels configured for stereo. So, 2n film caps on each side/channel. I got the results shown in pic 2. The increaseing of the residual noise level is obvious. A close up of this noise shape is in pic 4.
I have removed one of 1n caps on each channel, and then I got the noises shown in pic 3. The same shape, but not just in phase as before. Quite strange...
I have used for audio test a recording which it have a very good definition of the sound stage, with instruments and voice well and easy to locate in the sound stage. Playing this recording in normal conditions, it give me the voice not just in centre, but a little bit off centre, on the left hand side (between speaker and centre). Listening this recording with the caps (2n) over the DAC phases (differential output), I got the voice just in opposite side (right) but almost the same distance off centre. The rest of the instruments were in the same places... Even more strange...
The sound stage, paying back that recording with the caps in place, was not very special well (defined), but acceptable.
Removing the caps, everything was back to normal, with a very good definition of the sound stage.
My conclusions so far: There is enough obvious that in case of ES9018 chip, these caps increase the residual noises level on output, when one do not filter out these.
I can not expect something good, after heaving this experience, even with filters between I/V and final...
I could see a decrease of the noise amplitude after I have mounted 2n, than in the configuration with 1n. It may mean this that increasing even more the capacity over phases it may have positive impact? I did not proceeded yet to this experiment...
For me, the best result so far is not to have these caps over the DAC phases, when about ES9018...
I just start to think if the resulting effect (larger sound stage) when using these caps in that places is not a kind of psycho acoustic effect, due to some modifications/alterations in signal phases, or an effect due to the AC coupling in between of the DAC differential outputs (phases), when these caps are in that place...
It could be nice to have some more peoples involved in finding out more about this case, but it looks to me that the interest for the subject is quite low...
Well, I had in the last time the opportunity to take a closer look at this filtering trick, this time for ES9018 chip. BTW, it worked and it still work just fine for me on PCM1792.
In my system with ES9018, I use a post DAC signal processing without any filtering of the residual DAC HF noises. I have reduced their levels at under 100mV, for a useful audio signal of 12-16 Vpp, so is fine for me. My output on the L/R channels looks like in the pic 1
The probes are connected directly to the L/R channels output (no any audio signal). BTW, this residual HF noise is present only when the clock signal is active at the DAC clock pin.
I have connected 2x1n between the ES9018 differential output phases on its channels configured for stereo. So, 2n film caps on each side/channel. I got the results shown in pic 2. The increaseing of the residual noise level is obvious. A close up of this noise shape is in pic 4.
I have removed one of 1n caps on each channel, and then I got the noises shown in pic 3. The same shape, but not just in phase as before. Quite strange...
I have used for audio test a recording which it have a very good definition of the sound stage, with instruments and voice well and easy to locate in the sound stage. Playing this recording in normal conditions, it give me the voice not just in centre, but a little bit off centre, on the left hand side (between speaker and centre). Listening this recording with the caps (2n) over the DAC phases (differential output), I got the voice just in opposite side (right) but almost the same distance off centre. The rest of the instruments were in the same places... Even more strange...
The sound stage, paying back that recording with the caps in place, was not very special well (defined), but acceptable.
Removing the caps, everything was back to normal, with a very good definition of the sound stage.
My conclusions so far: There is enough obvious that in case of ES9018 chip, these caps increase the residual noises level on output, when one do not filter out these.
I can not expect something good, after heaving this experience, even with filters between I/V and final...
I could see a decrease of the noise amplitude after I have mounted 2n, than in the configuration with 1n. It may mean this that increasing even more the capacity over phases it may have positive impact? I did not proceeded yet to this experiment...
For me, the best result so far is not to have these caps over the DAC phases, when about ES9018...
I just start to think if the resulting effect (larger sound stage) when using these caps in that places is not a kind of psycho acoustic effect, due to some modifications/alterations in signal phases, or an effect due to the AC coupling in between of the DAC differential outputs (phases), when these caps are in that place...
It could be nice to have some more peoples involved in finding out more about this case, but it looks to me that the interest for the subject is quite low...
Attachments
Last edited:
You need to look a the output in the frequency domain to get an idea of the ultrasonic component. It will be proportional to the signal level making it harder to see on a scope.
I think you are saying that the output low pass caps increase the ultrasonic noise? if you are seeing that I would suspect an error in the application somewhere. My concern is that anything that demands a lot of transient current on a system (which this does) will stress the inner circuits a lot. I would rather see inductive filters in series to reduce the transient current demand.
I think you are saying that the output low pass caps increase the ultrasonic noise? if you are seeing that I would suspect an error in the application somewhere. My concern is that anything that demands a lot of transient current on a system (which this does) will stress the inner circuits a lot. I would rather see inductive filters in series to reduce the transient current demand.
- Status
- Not open for further replies.