[KeithEmo]

I agree....
That is the way I've always seen the description of how we hear a sound and identify its frequency.

HOWEVER, according to many recent studies, there seems to be a lot more stuff going on in terms of how our nervous system and brain process incoming audio, and what the various nerves attached to them are able to differentiate. For example, in some cases, nerve signals originating at our two ears are time shifted and subtracted. This system is consistently claimed to enable us to hear differences between our two ears of as little as 10 microseconds. I am providing that as an example of how sometimes our brain can extract information from what we hear that seems to be outside the range of what we can hear. As such, I very much DISAGREE that "we know all about how human eharing works"... and every recent book on brain science that I've read seems to agree.
My goal is simply to point out that the phenomenon of "human hearing" is quite a bit more complex than "a simple biological spectrum analyzer" - which is what you illustrated.

These guys seem to be talking about being able to detect differences in arrival time as small as 10 microseconds...
https://www.sciencedaily.com/releases/2014/04/140411103138.htm

And here's an interesting paper - from MIT.
This one describes how, independent of the frequency of a sound, we can detect differences in arrival times between our two ears as small as 10 microseconds.
http://web.mit.edu/2.972/www/reports/ear/ear.html

And these guys are looking for article submissions on the direct effect of ultrasonics on nerves.
They seem convinced that ultrasonic cignals, up to around 500 kHz, affect things like emotion directly.
https://bmcneurosci.biomedcentral.com/about/transcranial-ultrasound-stimulation

And here's an interesting lecture - from Princeton - about how and why we sometimes hear things that aren't there.
The slide on pg38 is interesting.... it shows how adding noise can make sound with gaps more intelligbile.

They all seem to agree that we still have a lot to learn about how human hearing actually works.

this is the basic principle and as far as we know, how we hear. just that the apex area of the basilar membrane is in fact wider than the base, and the extreme values are kind of BS, but the graphs on the right help understand what I'm trying to say, so I show this one^_^. any vibration with a strong enough intensity can reach that area and shake the hair cells enough to trigger some electrical impulses. in fact you could even just have something shake the head regardless of what goes on in the ear canal, and still successfully trigger "hearing"(like bone conduction and stuff like that, which are really all just about shaking the hair cells enough to activate them).
now the cells "detecting" high frequencies are at the base, I have never seen anything challenging that tonotopic map of the receptors(given tones related to a position in the ear, and later to a position in the brain). when you send high freqs, the base is narrow and stiff and a rapid vibration is rapidly attenuated(if it wasn't already while traveling to get there inside the head). so high frequencies will significantly shake the entrance of the basilar membrane(the bigger the amplitude the bigger the area that's going to shake, but the resonance is going to be at the entrance.

now if we have a 2khz vibration, it will propagate further down and resonate wherever the shape create the resonance for 2khz. the hair cells in that area will be shaken more than the rest but everything from the base to that 2khz area is also shaking, and then the vibration will get reduced and probably won't shake anything in the area for low end frequencies.


a 60hz tone now. it will create a traveling wave all the way down that hopefully will still reach a place where it resonates so we can identify it by its tone(although that low we start to have the body shaking to go with it anyway).

on the B C D examples in the graph, despite the caricature and the tube being straightened up, what is true is how the base tends to shake significantly no matter the frequency of the tone. that is the reason why that's where we usually lose our hearing the fastest. stronger amplitudes and all sounds causing movements. but the implication is also that when you have a mix of signals, for the 19, 20 or 25khz to be identified for what it is, we cannot afford to have the rest of the music creating bigger vibrations at the base of the basilar membrane. otherwise we get masking, the same way we get it in frequencies close to the resonance point of any tone. if a tone is 5khz, it will resonate massively in the 5khz area and that will also shake things directly next to that area, even though it won't resonate like at 5khz. so if at the same time we have a 4.5khz signal, but the amplitude of the shaking even at the resonance point is still smaller than the shaking from the 5khz bringing each sides for the shaky ride, then we have no way of knowing that the 4.5khz tone even existed. it is masked.
this can happen for ultrasonic and probably for a bunch of the higher treble freqs too, when almost any other tone played at the same time. it's all a matter of amplitudes(how loud it is, and how well it will be carried into the ear. as after all, our sensitivity changes a good deal for very low and very high frequencies).

so we need:
- the ultrasonic content to be recorded without much attenuation from distance or the mic rolling them off.
- same thing for playback gears. while it's not hard to find headphones with stable and extended ultrasonic content, that may not be what we own.
- we need to have ears with that area not damaged so much that it's either dead or firing signals all the time as noise(which does happen in small proportions everywhere even for "good" ears, explaining in part why we do have hearing thresholds in the first place, the other reason being how neurons don't necessarily activate with any level of signal they receive).
- those ultrasonic signals to reach the cochlea and still have enough amplitude to shake things around the base of the basilar membrane.
- and that needs to be bigger than all the already occurring shaking at the base, caused by the rest of the music. because those cells can't possibly identify such frequencies with the period of the vibration, the cells are rather slow to reload once they have fired(I'm guessing potassium and whatever else like in almost everything electrical in the body). I remember watching a video with a guy measuring individual hair cells potentials from rat ears or whatever, but I can't find it when I need it.there was a lot to learn from, and also a few mysteries.

can we get all that? yeah it's possible, young with the right gear and the right track, and maybe we'll perceive all that. and maybe even when we don't notice consciously, our brain will subconsciously. but let's just agree that the chances aren't on ultrasounds' side.

 

[bigshot]

Wouldn't it be a heck of a lot easier to just reacquaint yourselves with the M&M study?

I like to double check stuff with my own ears and equipment if it's a simple test like this. I did the same with CD-R generation loss, AAC generation loss, vinyl rips vs the LP, compression codecs, digital player transparency, amp transparency, headphone EQ, etc. Doing the tests for myself gives me a practical basis for my understanding that some folks who operate purely in theory seem unable to grasp.

Btw, I'm not sure you can do that test on a SACD player, all the ones I've come across have a [probably intentional] delay when switching between layers, and how would one be certain that the analogue circuits relating to the 44.1 DAC are of similar quality to those related to the DSD DAC?

Two players synced as closely as possible. In my test, I threw all the limitations on the CD side and it still didn't make a difference. They sounded identical.

 

[KeithEmo]

That was my impression.

I've read the Oohashi study, and several of the so-called "debunkings" of it.

It is quite noteworthy that Oohashi chose to use some relatively unusual recordings of some very specific instruments - and described why those in particular were chosen. Now, when attempting to scientifically confirm or contradict results in an experiment, the first step is usually to try to duplicate the experiment exactly - both to see if your results agree and to enable you to pick out possible weakness in methodology and just plain experimental error. However, I do NOT remember reading anyone who tried duplicating his test using the same sample recordings of the same rather unusual instruments. Instead they chose to try and contradict his results - using different equipment and different samples. (He listed the specific sample recordings he used... so they were available for use.)

Therefore, while several others pointed out some flaws in his test methodology, and conducted DIFFERENT experiments that failed to duplicate his results, they were never actually directly "debunked" at all. For example, one example noted that there was significant IM distortion in some of Oohashi's equipment, which could have produced errors in the result. But they neglected to then duplicate his experiment exactly, using the same sample content, but correcting that single error, to confirm that it had caused erroneous results.

(Sadly I didn't keep the links... )

From what I've been gathering, it's just Oohashi's conclusions regarding listener preference that have been discredited. But not his findings about physiological brain response to high-frequency audio. If you have more in-depth informaton, I'd appreciate a link to the source.

IMHO, it's an entirely different question to ask whether an ultrasound stimulus will trigger a human brain response in the auditory cortex, or whether we can distinguish Hi Res from RBCD in a conscious listening test.

FWIW, here's the most comprehensive summary on the former question that I've found:

Spoiler: Perception of Ultrasonic Sounds

12. Perception of Ultrasonic Sounds
The frequency range of human hearing is normally defined as extending from 20 Hz to 20 kHz
(Newby & Popelka, 1985). This range is commonly referred to as the sonic range. The lower limit
of hearing (20 Hz) is defined by the lowest frequency at which the listener hears one continuous
sound. The upper limit of hearing (20 kHz) is defined by the highest frequency at which the
listener still has an auditory sensation, regardless of sound intensity. The highest frequency
perceptible differs greatly among individuals and is difficult to determine because some high
frequency sounds can cause a painful or a tactile sensation but not an auditory sensation. In
addition, some investigators have noted that the operational (normal) range of human hearing may
be extended to frequencies beyond 20 kHz when the ear is stimulated by bone conduction as
opposed to air conduction. Ultrasonic frequencies refer to frequencies above the range of air
conduction hearing (greater than 20 kHz), and the human ability to hear sounds in this frequency
range is normally referred to as ultrasonic hearing.
Although air-conducted sounds cannot be heard at frequencies above 20 kHz (Wever, 1949),
ultrasonic hearing as high as 100 kHz has been demonstrated through bone conduction stimulation.

150
Ultrasonic hearing has been found to be capable of supporting frequency discrimination and speech
detection in normal and older people with severe and profound hearing loss. One of the first
groups of investigators to report perception of ultrasonic frequencies by bone conduction demon-
strated this phenomenon by generating ultrasound waves in water (Deatherage et al., 1954). First,
auditory perception was noted when a listener’s jaw bone was placed in contact with a container
filled with water in which a transducer produced a signal of 50 kHz. The threshold for this signal
was approximately 2000 dynes/cm2, which equates to about 140 dB SPL. Second, auditory
perception was demonstrated through submersion of the listener in a container of water containing
the transducer. In this condition, the threshold was approximately 1000 dynes/cm2 at 50 kHz,
which equates to about 134 dB SPL. To support their claims that the vibrations were being
perceived by bone conduction, Deatherage et al. (1954) showed perception of a 7-kHz signal in
a body of water at a threshold of 12 dynes/cm2, which agreed well with previous bone conduction
threshold data obtained by Bekesy using direct mechanical stimulation.
Since this early report of auditory perception of ultrasonic stimuli delivered through bone
conduction, several investigators have pursued measurement of the human auditory system’s
sensitivity and discrimination ability in the ultrasonic range. For example, Corso (1963) evaluated
high frequency sensitivity to bone-conducted sounds by people with normal air conduction hear-
ing. Placing vibrators on the mastoid bone, Corso measured bone conduction thresholds for
frequencies between 6 and 95 kHz and reported good sensitivity for frequencies below 14 kHz and
poor or no sensitivity to sounds of frequencies between 20 and 95 kHz. In contrast, a later study
demonstrated that the sounds in the ultrasonic range can be heard by listeners (Lenhardt, Skellet,
Wang, & Clarke, 1991).
The mechanism through which ultrasonic sound is perceived by the listener is not known, although
several theories exist. These theories include
• Perception by the saccule within the vestibular system,
• Demodulation of the ultrasonic stimulus through the bones of the skull, which is then
perceived by the cochleae,
• Direct stimulation of the brain matter and cerebrospinal fluid, and
• Direct stimulation of the cochleae through the brain.
The first theory is that the bone-conducted sound is perceived by the saccule, one of the three
vestibular canals present in the inner ear, as demonstrated through the perception of ultrasound in
people with nonfunctional cochleae (Lenhardt et al., 1991). Figure 79 is a diagram of the cochlea
for review. In order to accept the saccule theory, the traditional pathways need to be eliminated
first (Dobie, Wiederhold, & Lenhardt, 1992). In support of this effort, several investigators have
demonstrated that ultrasonic stimulation through bone conduction cannot be masked through air
conduction which leads away from a cochlear-based process. Furthermore, ultrasonic signals
presented through bone conduction cannot be measured in the EAC (Staab et al., 1998).


151
A second theory about the perception of ultrasound is that the bone conduction process is suffi-
ciently nonlinear to demodulate the signal (Dobie et al., 1992; Lenhardt et al., 1991). Demodula-
tion refers to the perception of a frequency that is within the audible range that represents the
fluctuations of the carrier signal. According to this theory, the presentation of ultrasonic vibrations
to the skull does not allow for transfer of these vibrations through the middle ear to the cochlea but
to the cochlea directly. The cochlea then demodulates the signal into a range where it can be
heard.













Figure 79. Spatial relationship between the structures of the vestibular system,
the cochlea, and the celebrospinal fluid (CSF) spaces (Salt, 1996).
Several investigators have argued against the theory of the bone conduction pathway for ultra-
sonic perception following an examination of ultrasonic stimulation through the use of magneto-
encephalography (MEG) (Hosoi et al., 1998). In this procedure, areas of the brain are examined
through a scanning device to determine where neurons are activated in response to a particular
stimulus. Hosoi and colleagues (1998) stimulated listeners who had normal hearing with ultra-
sonic sounds by placing a vibrator on their sternocleidomastoid muscle (between the neck and
shoulder). They found brain activity in response to these stimuli in the auditory cortex. This was
true for people with normal hearing and for those with profound hearing loss. Imaizumi et al.
(2001) found the same results using positron emission tomography scans. Again, stimulation in
people with normal hearing or profound hearing loss resulted in activation of the auditory cortex.
This activation occurred through stimulation by air conduction, bone conduction, ultrasound and
vibro-tactile methods (Imaizumi et al., 2001). Regardless of the pathway or mechanisms behind
the phenomenon, it has been demonstrated that ultrasound can be perceived by the listener when
vibrations are applied directly to the human head or neck.
When an ultrasonic carrier signal, which is presented to the listener through bone conduction, is
amplitude modulated by a speech signal, the result is a clear perception of the speech stimuli and
not a sense of high-frequency vibration. In a study by Lenhardt and colleagues (1991), speech
recognition rates through this method for people with normal hearing were on the order of 83%

152
for the WIPI (word-identification through picture identification) task. For people with profound
hearing losses (pure tone averages of greater than 90 dB HL), performance in the same test was
between 20% and 30%. These results support the belief that ultrasonic hearing may be used as a
communications channel and thus as a non-surgical approach in the rehabilitation of profound
hearing losses. The results also imply that ultrasonic stimulation for speech communication may
be applicable for people with normal hearing.
An amplification device using ultrasonic stimulation through bone conduction called HiSonic was
developed by a group of investigators in Arizona (Staab et al., 1998). This device was developed
for use with people with profound hearing loss for whom standard hearing aids would not provide
sufficient amplification. Such a device would allow a non-surgical alternative to cochlear implants
as a hearing solution (see section 10). The device consists of a bone conduction vibrator that is
positioned on the mastoid bone of the wearer. In the Staab et al. (1998) study, pure tone stimuli in
the range of 500 to 2000 Hz were shifted in frequency to the ultrasonic range, and thresholds were
measured for listeners with normal hearing as well as those with profound hearing loss. For the
people with profound hearing loss, a comparison of thresholds measured with and without the
ultrasonic shift showed a clear advantage of using the HiSonic device in that thresholds obtained
with the device were considerably lower than those obtained without the device. Although there
was considerable variability among the performance of the individual listeners, benefit through use
of the device was demonstrated in 65% to 70% of the participants (Staab et al., 1998).
The third theory about a mechanism for ultrasonic perception is that the skull vibrations are
being transmitted directly to the brain and surrounding CSF, including direct stimulation of the
auditory cortex. Skull vibrations can be transmitted to the cochlear fluids and to the non-com-
pressible brain matter and the surrounding CSF. The resulting changes in fluid pressure can be
transmitted through the internal auditory meatus and cochlear aqueduct to the perilymph of the
scala tympani or through the vestibular aqueduct to the endolimphatic sac of the vestibular
system and further to the saccule (see figure 79). This mechanism of bone conduction was
proposed as an alternate pathway explaining the presence of auditory sensation during direct
stimulation of brain tissue and the CSF. However, the hypothesis of the vibration transmission
from the CSF to the cochlear fluids is contradicted by relatively high mechanical damping of
structures (neurons, blood vessels, connective tissue) occupying the aqueducts (Bystrzanowska,
1963, p. 19).
The fourth theory about the mechanism for ultrasonic perception is a mechanical conduction of
sound to the cochlea proposed by Freeman et al. (2000) and Sichel, Freeman, and Sohmer
(2002). This mechanism involves direct excitation of the CSF in the skull cavity. The CSF is
the watery fluid that occupies the spaces around the brain and the spinal cord providing shock
absorption protection to these organs. During some conditions, this fluid can enter the cochlea
from the subarachnoid space that is connected to the scala tympani through the cochlear aque-
duct (diameter ˜0.5 mm). The investigators in these two studies directly vibrated the brain matter
of rats, guinea pigs, and fat sand rats and demonstrated that direct stimulation of the brain


153
through a bone oscillator resulted in measurable ABRs. Progressive elimination of potential
bone conduction mechanisms (i.e., ossicular chain, meatus, and skull through craniotomy) did
not result in complete elimination of the ABR. This finding supports the notion that an auditory
sensation can arise from direct vibration of the brain and CSF. The difference in the inter-
pretation of the mechanism involved is in the identification of the location of perception. The
hypothesis that auditory stimulation of the brain and CSF is possible is also supported by some
results of human studies (Sohmer et al., 2000). The studies did not eliminate direct stimulation
of the auditory cortex as was theorized by others but theorized that the stimulation was directly
detected by the cochleae.
The use of ultrasonic stimulation is not without its contraindications. Several investigators have
noted tinnitus of several days’ duration as a side effect associated with the ultrasonic stimulation,
which could be an early sign of hearing damage (Corso, 1963; Deatherage et al., 1954). This
side effect is not to be taken lightly. In order to consider the use of ultrasonic stimulation for any
person, the safety of that provision must be carefully considered. To our knowledge, there are no
reports about the safety aspects of the provision of ultrasonic stimulation of the bones of the
skull. Until those data are made available, long-term use of ultrasonic stimulation should be
avoided.
In summary, there is evidence to suggest that ultrasonic frequencies can be perceived as sound
by the listener when they are transmitted through bone conduction vibration on the skull. The
pathway for such perceptions is not clear, but four theories have been proposed, ranging from
demodulation by the auditory mechanism to the detection of sound by the CSF within the skull
cavity. Caution should be used when one is attempting to implement ultrasonic stimulation since
there is little known regarding the safety limitations. There have been some reports of the onset
of tinnitus following stimulation by ultrasound.

(source: link; warning: huge document)

 

[KeithEmo]

Geeee.....

If I've got a microphone with an inherent noise floor of 50 dB, a dynamic range of 172 dB, and a FR to 70 kHz....
That means it's got a USABLE dynamic range of over 120 dB....
So I'd insert a 30 dB attenuator between the microphone and the preamp.....
Then the inherent noise floor at the output would drop to 20 dB... and it still wouldn't overload at 142 dB.
(But, then, if I'm recording something at 140 dB SPL, I doubt the 50 dB noise floor would matter much.)
Seems pretty possible to me... right here and now...

1. NO you are not talking about scientific measurements and NO, we do not "tend to look at things differently"! The laws of physics exist and are always applicable, unless you're in some alternate universe. What you're actually doing is making up nonsense and then passing it off as "science", so in fact you're actually perverting the science and are thereby insulting this forum!
2. Inherent noise of 50dB makes it almost unusable for recording musical instruments but regardless, it does NOT have "an inherent noise of 50dB" anyway! The 50dB figure is "A" weighted and due to rising thermal noise with freq (which is real science and in this universe!) the mic will have far higher self-noise in the ultrasonic range.
3. EXACTLY!! It's your "guess" and that guess is based on "inadvertent" errors which fortuitously just happen to support your agenda . How is that even slightly "science"? It's pretty much the exact opposite of science! Instead of making up nonsense claims and falsely passing it off as science, why don't you actually try just the very first step of science and get a musician to perform on cymbals, use this mic to record them and then see for yourself if it will record "everything up past 70kHz"??
4. I do have a measurement mic, in fact more than one.
4a. But you're NOT discussing what's possible! I'm discussing what exists and what's possible BUT you're discussing what's possible in some alternate universe where you get to choose which laws of physics apply!

Continuing for those interested in the actual facts (in this universe!) ...
1. Ask yourself the obvious question, if this mic is so accurate/perfect why is it "nobody ever does it that way", why don't we always record with calibrated measurement mics? In short, there is no such thing as a perfect mic, they must always be compromised: You cannot have a mic with a very low noise floor, a very accurate freq response and resilience to high SPLs. In practise (in this universe) it's a trade-off, you improve one of these areas at the cost of another. Some specialist measurement mics are designed to measure very low SPLs and therefore have very poor resilience to high SPLs and typically poor freq accuracy. Other measurement mics are designed for highly accurate frequency measurement but at the cost of a very high noise floor (which isn't typically a problem because they are designed to be used with optimal/high level test signals). However, the performance of a musical instrument is not a test signal, there will be both loud and quiet elements: A snare drum for example will have a loud impact transient, immediately followed by the relatively quiet sound of the snares sympathetically vibrating against the bottom head and additionally, not every snare hit will be very loud, there will almost certainly be grace notes/flams which are far quieter, and, this effectively applies to all musical instruments. The reason that "nobody ever does it that way" is because these quieter elements would be below the noise floor of a measurement mic (such as the one KeithEmo cited). And, that's even in the audible freq band, let alone the ultrasonic band where the measurement mic will have an even higher noise floor! We always use music/studio mics rather than measurement mics to record music because music/studio mics are optimised for recording music in studios (duh)!
2. This statement is FALSE! Every commercial studio I know of has at least one measurement mic and these days, also studio mics which extend into the ultrasonic range.
3. It wouldn't "sound" at all, if it's below the noise floor of the mic!
4. That as well!
5. And I would remind anybody coming in late that what we're discussing here is the science applicable to recording commercial audio, the stuff that your audio reproduction system is reproducing. KeithEmo on the other hand is discussing certain bits of science and "inadvertently" ignoring the other relevant bits, inventing hypothetical scenarios which never exist and misrepresenting what is science and what is recording technique, which is particularly absurd as he clearly doesn't know anything about recording technique and refuses to try some recording tests and actually find out!

1. Firstly, how are you going to sit 3 feet from the band, they're all going to be standing/sitting in a tiny circle around you are they? In this universe, the audience is typically going to be sitting in front of the band (with the drumkit at the back of the band) and therefore many meters away from the cymbals. At many meters away from the cymbals there's going to be a great deal less ultrasonic content than the only 6% they're producing in the first place, rolling off the very high and ultrasonic content of closely mic'ed cymbals is not an artistic decision, it's a technical decision based on the laws of physics. Not rolling-off those freqs would be an artistic decision but as human perception partly relies on the attenuation of high freqs at distance, you'd effectively end up with the cymbals sounding much closer (more present) than the rest of the drumkit.
2. Again, you're joking right? You seem to have this bizarre notion that sound engineers pick the worst mic they can find and never test or experiment with anything. This notion is ridiculous and the exact opposite of the actual facts/truth! The recording of breaking glass is so common in film and TV that Foley teams always have a large crate of glass in their store rooms and the recording of breaking glass has been tested to death with just about every mic imaginable, in just about every position by thousands of different engineers all over the planet for decades. Personally I only have mics that go up to 40kHz, so not 50kHz but still plenty of ultrasonic content and no, it does NOT sound more realistic, either for me or for the countless other engineers, sound designers, Foley artists, Directors, etc. In fact, generally less so because generally the glass is breaking more than just a few inches from the sound POV and therefore has attenuated high freqs (and ultrasonic freqs).
3. A lot of what you keep saying on this forum boils down to: "I have absolutely no idea what extensive testing has been carried out by thousands/tens of thousands of engineers over the course of decades, so I'm just going to make-up an "inadvertent" misrepresentation that it's never been tested and everyone who disagrees with me is just guessing. I on the other hand have never tested either and refuse to do so but my guesses are worth more than the actual facts. According to me, that's SCIENCE!".
4. Firstly, there's clearly a big difference between the amount of evidence which exists and the amount of evidence you personally know about. Time and again audiophiles state "we don't know this or that", when in fact it's perfectly well known, often for many decades or even centuries, it's a fallacy based entirely on their own IGNORANCE of the facts. Just because they don't know doesn't mean that we (science/mankind as a whole) don't know. There's a mass of evidence, by (as mentioned) the engineers who work with the content every day, industry bodies such as the AES, EBU, ITU (and others), state organisations such as the BBC, NHK (and many others) and some published scientific papers as well. Secondly, this is NOT the "What KeithEmo Strongly Believes" forum!!
5. Then why do you keep doing it??? Why don't you AS AN INDIVIDUAL actually learn some of the facts/evidence, why don't you take YOUR OWN ADVICE and try recording some drumkit solos (and breaking glass) with measurement and other mics and until you do, why don't you STOP making far-reaching claims based on ABSOLUTELY NO EVIDENCE WHATSOEVER? How come you're not "always bugged" by yourself?

1. Just to be clear what you're effectively saying and the truth of the matter:
Ten years ago snake oil salesmen made a big marketing push for 192kHz audio files and 192/24 DACs. That marketing was successful, many/most consumers believed the BS and now demand 192kHz. So all the chip makers now only make 192kHz chips and you're just satisfying the market demand (for snake oil) that ten years ago you helped create. Of course, now that 192kHz is no longer a "product differentiator" and even very cheap DACs now include it as standard, the audiophile snake oil industry has to come-up with some new BS to act as a "product differentiator" (and justify their 10-100 times price premium), hence the next round of even greater snake oil; 32bit, 384kHz and 768kHz, just as 192kHz was the next round of greater snake oil over 96kHz.
2. Because either you'd have to fake the tests and run the risk of being found out and having potentially disastrous publicity or provide accurate tests demonstrating that you and the rest of the audiophile industry have been BS'ing and selling snake oil for well over a decade. That's a no win scenario and why neither your company nor any other audiophile company ever conducts or publishes such tests. To be certain, if there were an audible difference/improvement, the audiophile world would be awash with the test results!!

G

 

[bigshot]

I don't see the value in spending money for higher bit rates...but am always open to being convinced by a rational argument. That said, I will spend money for a better/different version of an artist's work.

A better/different version would be better mastering and perhaps remixing. Those things aren't dependent on format. There are terrible sounding SACDs and great sounding MP3 downloads. The best way to find better/different versions is to speak to collectors in music forums where there are people who have compared different versions carefully and have determined which are the best. Sometimes that is an old CD from the early 90s, sometimes that is a current blu-ray audio disc. The only way to tell which is the best is to listen. Price tag and bitrate aren't a good determiner of audio quality. That's my experience, and I have a house full of tens of thousands of 78s, LPs, cassettes, R2Rs, CDs, DVD-As and Blu-Rays that backs it up. I had one recording that meant an awful lot to me that I bought in multiple formats and releases over the years, only to discover that the best possible version was a 1935 78rpm first pressing on Z shellac.

You can't judge by the numbers. You have to judge by sound.

why is the hi-rez source material downsampled instead of the low-rez source material upsampled and then the test run by playing back through that resolution?

To guarantee that you are comparing the same mastering in "hi-res" as you are in 16/44.1.

 

[bigshot]

IMHO, it's an entirely different question to ask whether an ultrasound stimulus will trigger a human brain response in the auditory cortex, or whether we can distinguish Hi Res from RBCD in a conscious listening test.

I agree with that completely. When we listen to Mozart in our living room, we might smell the dinner cooking in the kitchen, see the color of the walls of the room, feel the texture of the fabric of the couch we are sitting on, and we can taste the glass of wine we're sipping... but none of that changes the way our stereo system reproduces sound. We're in a forum dedicated to high fidelity reproduction of music in the home. A brain wave tick in response to frequencies we can't hear won't make our recorded music sound any better. It's irrelevant to the reproduction of commercially recorded music because 1) it can't be heard, 2) it doesn't add anything to perceived sound quality, 3) frequencies that high aren't generally produced by musical instruments, and if they do produce them it's at a volume level likely to be masked, 4) those frequencies are generally not a part of commercial music mixes and 5) it's unlikely that our transducers can reproduce them in any balanced sort of way.

Super audible frequencies are irrelevant to the playback of commercially recorded music.

 

[dprimary]

If you really want to make a general test of "whether SACDs sound audibly different than CDs"....

You really need to use more than one SACD, more than one CD player, and more than one sample of each medium.
You also need at least a few samples which have been confirmed to contain what you're testing for.

Therefore, at a minimum, you must confirm three things....
1) you must confirm that the master used for both was the same
2) you must confirm that the entire sginal path of both productions took full advantage of the medium
3) you must confirm that your player is taking full advantage of both types of media playback
(if the analog signal path of your SACD player only extends to 20 kHz, then that is the limit of your test)

If you want to compare the high frequency response, or the ultrasonic response, of two different recordings...
Then you must first confirm that the master recording that both were produced from actually contained those frequencies.
Then you need to confirm that the rest of the signal chain hasn't failed to reproduce what you're testing for.
Then you need to confirm that the actual output of your SACd player is delivering both signal accurately.
(And you also need to confirm that your speakers, or headphones, aren't limiting the respons eeither.)

You can't tell whether 30 kHz is audible unless you start with a test signal that CONTAINS 30 kHz.
If you want to test whether the "ability" of an SACD to deliver ultrasonic frequencies makes a difference...
You must first confirm that the test samples you choose actually do so...

Proving that specific SACDs don't sound better doesn't prove whether ANY SACD CAN sound better or not.
It could trun out that most commercial SACDs are mastered badly and fail to live up to the potential of the medium.
(I would suggest that most CDs in fact fail to live up to the potential of the CD medium.)

NOTE that this isn't all that hard.
First you confirm, using proper test equipment, that the actual outputs of the two are in fact different.
Then you confirm, using proper test equipment, that your reproduction chain is delivering that difference to your ears.

I should also point out the obverse.....
If you simply want to test if there is a difference that is audible TO YOU ON YOUR SYSTEM....
Then performing the test using your system and your ears is perfectly adequate....

At the very least you should play both from the same model of player. While the conversation from D to A is different the rest of the chain would be the same reducing many variables. Ideally using a player that can output the full bandwidth of the two formats over the analog outputs. Switching between HDMI sources introduces a load of other problems. The CD source must be converted from the SACD to be sure it is the same master just bandwidth limited. It would be easier if you could filter DSD. If you could move the filter point on the DSD convertor down to 20k that would work.

 

[bigshot]

I've done this test. Maybe I'm the only one.

 

[analogsurviver]

I agree with that completely. When we listen to Mozart in our living room, we might smell the dinner cooking in the kitchen, see the color of the walls of the room, feel the texture of the fabric of the couch we are sitting on, and we can taste the glass of wine we're sipping... but none of that changes the way our stereo system reproduces sound. We're in a forum dedicated to high fidelity reproduction of music in the home. A brain wave tick in response to frequencies we can't hear won't make our recorded music sound any better. It's irrelevant to the reproduction of commercially recorded music because 1) it can't be heard, 2) it doesn't add anything to perceived sound quality, 3) frequencies that high aren't generally produced by musical instruments, and if they do produce them it's at a volume level likely to be masked, 4) those frequencies are generally not a part of commercial music mixes and 5) it's unlikely that our transducers can reproduce them in any balanced sort of way.

Super audible frequencies are irrelevant to the playback of commercially recorded music.

1.) true
2.) false
3.) false
4.) true for most production, BUT NOT ALL - particularly not recent native HR, whether DSD or PCM/DXD
5.) false; transducers that cover well up to at least 40 khz are with us for - at least - approx 40 years.

 

[bigshot]

There is absolutely no reason for you to read or answer my posts. I don't read yours. And I'm sure it works fine in your own head, but I doubt anyone else will get much out of a list of trues and falses without any context.

The sound you can hear is the sound that matters. Most of us probably can't hear much above 17kHz anyway. Regular old CD quality sound and high data rate lossy is plenty to achieve audible transparency. Anything beyond the range of human hearing is just packing peanuts to fill up a digital container with stuff you don't need.

 

[castleofargh]

I agree....
That is the way I've always seen the description of how we hear a sound and identify its frequency.

HOWEVER, according to many recent studies, there seems to be a lot more stuff going on in terms of how our nervous system and brain process incoming audio, and what the various nerves attached to them are able to differentiate. For example, in some cases, nerve signals originating at our two ears are time shifted and subtracted. This system is consistently claimed to enable us to hear differences between our two ears of as little as 10 microseconds. I am providing that as an example of how sometimes our brain can extract information from what we hear that seems to be outside the range of what we can hear. As such, I very much DISAGREE that "we know all about how human eharing works"... and every recent book on brain science that I've read seems to agree.
My goal is simply to point out that the phenomenon of "human hearing" is quite a bit more complex than "a simple biological spectrum analyzer" - which is what you illustrated.

These guys seem to be talking about being able to detect differences in arrival time as small as 10 microseconds...
https://www.sciencedaily.com/releases/2014/04/140411103138.htm

And here's an interesting paper - from MIT.
This one describes how, independent of the frequency of a sound, we can detect differences in arrival times between our two ears as small as 10 microseconds.
http://web.mit.edu/2.972/www/reports/ear/ear.html

And these guys are looking for article submissions on the direct effect of ultrasonics on nerves.
They seem convinced that ultrasonic cignals, up to around 500 kHz, affect things like emotion directly.
https://bmcneurosci.biomedcentral.com/about/transcranial-ultrasound-stimulation

And here's an interesting lecture - from Princeton - about how and why we sometimes hear things that aren't there.
The slide on pg38 is interesting.... it shows how adding noise can make sound with gaps more intelligbile.

They all seem to agree that we still have a lot to learn about how human hearing actually works.

your examples are about interpretation, and the ultrasonic link seems to not even be concerned about hearing at all. yes I present hearing as a sort of spectrum analyzer, or maybe more as a sort of really weird microphone. not because I believe that our brain can't do amazing stuff with the data from that sensor, but because if something can be masked or is simply outside the range of sensitivity of that sensor, then there will be no extra data to interpret. which seems pretty important to me when considering what might matter.

now if you want to use transcranial stimulation as an argument that ultrasounds even when not perceived by our auditory system can still affect our experience, I'm fine with that of course. but I'm not fine with considering that as hearing. and if like @Phronesis you wish to extend the notion of hearing beyond signals captured by our ears, and go deep inside the brain at a cellular level or just as a thought, I'm also fine with that but only so long as your notion of hearing is very clearly and strictly defined. because as of right not it isn't my definition of hearing. there are many non audio aspects that can trigger a change or even cause a reaction in the auditory cortex or anywhere else. just with the research available, we cannot doubt that to be true. but is it hearing? in a brain where our different senses are never strictly isolated(at least not when it comes to interpretation), one could argue that placebo is hearing. that touching is hearing. we even have people for whom the link between senses is more direct, and a sound will have a color or vice versa. but should we define human hearing with such standards?
when we agree in this section that all those non audio variables need to be eliminated in a listening test, we do imply that they all have the potential to affect our interpretation of sound. so all in all it's not a big move to go from our usual position to a position redefining hearing as a more global experience. but it's a very massive difference in definition!
even then, all we do is allow more variables to count as audio. even with that trick, demonstrating that the typical amount of ultrasounds in records is having a clear impact(a positive one!) on the listener, is still something I'm waiting to see. if anything I'd argue that if we open our definition of hearing to a wider range or variables, it automatically makes ultrasounds an even smaller part of what forms our audio experience.

 

[GearMe]

A better/different version would be better mastering and perhaps remixing. Those things aren't dependent on format. There are terrible sounding SACDs and great sounding MP3 downloads. The best way to find better/different versions is to speak to collectors in music forums where there are people who have compared different versions carefully and have determined which are the best. Sometimes that is an old CD from the early 90s, sometimes that is a current blu-ray audio disc. The only way to tell which is the best is to listen. Price tag and bitrate aren't a good determiner of audio quality. That's my experience, and I have a house full of tens of thousands of 78s, LPs, cassettes, R2Rs, CDs, DVD-As and Blu-Rays that backs it up. I had one recording that meant an awful lot to me that I bought in multiple formats and releases over the years, only to discover that the best possible version was a 1935 78rpm first pressing on Z shellac.

You can't judge by the numbers. You have to judge by sound.

Exactly what I was saying...a better version not a higher bitrate. Did you think I meant something else?

To guarantee that you are comparing the same mastering in "hi-res" as you are in 16/44.1.

Just clarifying this part of the test for my own sanity as it seems this thread has been all over the place. I would think you'd want to get a well-recorded source/master with verified hi-rez content, (i.e. recorded with 'hi-rez' equipment, includes > 20kHz content, no compression, etc.) and compare it to the same 'limited' source/master (<=20kHz content). Then, you'd want to upsample the 'limited' copy to the native resolution of the 'hi-rez' copy, play both of them back through gear that is designed/capable for the 'hi-rez' applications, and do the DBT on that...yes?

 

[bigshot]

Right. When I did my test I used an SACD that was recorded natively in DSD. That guaranteed super audible content. It sounded exactly the same as the same in CD quality sound.

 

[gregorio]

Geeee.....
If I've got a microphone with an inherent noise floor of 50 dB, a dynamic range of 172 dB, and a FR to 70 kHz....
That means it's got a USABLE dynamic range of over 120 dB....
So I'd insert a 30 dB attenuator between the microphone and the preamp.....
Then the inherent noise floor at the output would drop to 20 dB... and it still wouldn't overload at 142 dB.
(But, then, if I'm recording something at 140 dB SPL, I doubt the 50 dB noise floor would matter much.)
Seems pretty possible to me... right here and now...

Geeee ..... What's the name of this thread, is it "Refusing to test audiophile claims and myths (and just make-up a bunch of new ones)" or is it pretty much the exact opposite of that? Why don't you take YOUR OWN ADVICE and record a few drumkit solos with your wonder mic??

For everyone else (in this universe):
KeithEmo is suggesting the use of a very specific type of piezoelectric measurement mic. This type of measurement mic has the advantage of being able to withstand extremely high SPLs and is designed for measuring shock waves! As mentioned previously there is always a trade-off, there is no perfect mic, you can't have a mic capable of such extreme SPLs which still performs as well as other mics in other respects. The trade-off for these types of measurement mics is that they have very poor sensitivity and very high self-noise. Unfortunately, KeithEmo "inadvertently" omits to mention the sensitivity issue and proposes to simply pad (attenuate) the output by more than 30 times to reduce the self-noise. In other words, he proposes taking a mic with very poor sensitivity and effectively reducing it's sensitivity by a further 30 times?!

Just to be clear what we're talking about here: This measurement mic has a sensitivity spec of -60 1V/Pa, which means that with a 94dB SPL signal the mic will output just 1 millivolt. This output level is already BEYOND the ability of studio mic pre-amps to amplify to a useable level (line level) and KeithEmo is proposing to reduce it by another 30 times?!

For what this mic is designed for, 1 millivolt from a 94dB input is not a problem because it's designed for far higher input SPL levels (up to nearly 10,000 times higher!). In other words, if we get this mic close enough to a cymbal and hit the cymbal hard enough to produce a transient peak of 124dB SPL, the output level of this mic with Keith's attenuator would be a single millivolt and once the fraction of a second of the cymbal's transient peak was over and we're into the decay phase of the cymbal hit (and therefore SPLs many times lower than the initial impact/transient peak), what then? KeithEmo's statement "it will record everything up past 70 kHz" - actually means it will record (at a very low level) a transient peak lasting a few milli-seconds and then pretty much nothing! Of course, if KeithEmo actually took his own advice and tested his claim, he would see for himself how ridiculous it was.

There's a good reason we don't use mics designed to measure shock waves for recording music and it's got nothing to do with artistic decisions and everything to do with simple physics! We can all ignore certain facts and realities and then virtually anything would "seem possible to me ... right here and now...". If for example we ignore the law of gravity, it would "seem pretty possible" that pigs could fly. However, this is the sound SCIENCE forum, gravity does exist and pigs cannot fly!

In addition to all the above, you (KeithEmo) cannot just keep repeating falsehoods even after they've been shown to be false. You specifically chose this mic as an example due to it's ultrasonic freq response (and high SPL capability). However, it's specified 50dB noise floor is an "A Weighted" measurement, which means at 20kHz it's noise floor is most likely double the 50dB figure you're quoting and by 70kHz it's probably around 3-4 times higher but could be as high as about 90dB. As has already been explained, the law/rule of thermal noise demands that the noise floor is higher at higher freqs, so you already know the 50dBA noise floor figure is inapplicable/false in the ultrasonic range, yet you repeat it as a true/applicable fact anyway, why is that?

G

 

[Phronesis]

This is what I'm gleaning at this point regarding ultrasonics:

- They're produced by various musical instruments (usually transiently) and in nature and the built environment at meaningful levels. Hence many species being able to hear far above 20 kHz.

- It's possible to record and reproduce these very high frequencies with gear, though that's not usually done.

- These high very frequencies may produce brain responses in auditory regions via pathways which bypass the eardrum, such as through the skull and eyes.

- Some people can consciously perceive these very high frequencies. Others may perceive them only subconsciously. The thresholds for these effects vary a lot between people.

- The effect of accurately recording and reproducing these very high frequencies with respect to music enjoyment is uncertain. It may vary among people.

- If the effects of these very high frequencies are via pathways which bypass the eardrum, headphones may not be a viable option to produce them, and attempting to produce them via headphones may actually be detrimental for music enjoyment.