• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

"Things that cannot be measured"

Katji

Major Contributor
Joined
Sep 26, 2017
Messages
2,990
Likes
2,273
@Coach_Kaarlo , thank you. *very much.* Now I can stop stressing about it. I'd been thinking I should start making notes, preparation, otherwise any attempt I made would become extreme.
 

Coach_Kaarlo

Active Member
Joined
Apr 27, 2020
Messages
196
Likes
222
Location
Sydney
What's your evidence for 'Much of what we sense remains beyond our perception yet readily produces emotions, thoughts, and behaviour.' How could that ever be demonstrated one way or the other? If it 'readily produces emotions...etc.' then how can it be 'beyond our perception'?

Try Huberman Labs, some good content on the topic.

Or google?

Sensation and perception are two separate processes that are very closely related. Sensation is input about the physical world obtained by our sensory receptors, and perception is the process by which the brain selects, organizes, and interprets these sensations. In other words, senses are the physiological basis of perception. Perception of the same senses may vary from one person to another because each person’s brain interprets stimuli differently based on that individual’s learning, memory, emotions, and expectations.

[ Edit: neuroscience, behavioral economics, evolutionary biology, psychology, A.I. and machine learning, etc etc - have all been the focus of some self directed learning over the last 5 years. The nature of my work allows me 3-4 hours a day to consume this diverse content, process it, relisten to the content, and finally understand about 1% of it, and be able to explain 0.01%......I highly recommend it though - well worth the effort regardless.

However, the reason I decided to post something was I recognised certain patterns of behaviour pervading almost all areas of discussion in ASR, and equally after almost a year recognised the same individuals making the same comments about completely different topics or subject matter.]
 
Last edited:

Coach_Kaarlo

Active Member
Joined
Apr 27, 2020
Messages
196
Likes
222
Location
Sydney
So - is it 'perception' or 'beyond perception'?

Some things may be beyond perception until one becomes aware of the sensory input.

Trained listeners perhaps are an example? Their hearing ability (sensory input) remains unchanged, but they hone their perception.

So I think perception is fluid, but sensory input is fixed.

Oliver Saacs has some great content relating to perception and the senses - people with brain injuries and interesting sensory input / perception combinations.
 

Sawdust123

Member
Joined
May 3, 2019
Messages
49
Likes
160
Bruce Hofer, co-founder and analog genius behind Audio Precision has given several papers regarding nonlinearities in real world passive components. Capacitors and resistors will vary in value with voltage and current and heat. This variation will have linear and higher-order terms. Self heating will be a function of component size and frequency. In a prior life, I used to deal with the modeling of RF transistors and there were separate models for transient response and steady state. There is no reason to assume such issues don't exist at audio frequencies. ESS has a talk about how state variable changes within a converter can create audible noise problems. The point of mentioning all this is that we already have the science that explains why transient responses will be different than steady state responses yet the vast majority of our testing is steady state.
 

Xulonn

Major Contributor
Forum Donor
Joined
Jun 27, 2018
Messages
1,828
Likes
6,311
Location
Boquete, Chiriqui, Panama
and putting a stop to the activities of the village wind band (where I play the tuba).
A high school band in Wenatchee, Washington, USA, came up with the Covid-19 pandemic safety idea of putting band members in tall, skinny tents for indoor practice/rehearsals. It was a bit cramped for the tuba player...

Tuba - Tent.jpg
 

scott wurcer

Major Contributor
Audio Luminary
Technical Expert
Joined
Apr 24, 2019
Messages
1,501
Likes
2,822
Bruce Hofer, co-founder and analog genius behind Audio Precision has given several papers regarding nonlinearities in real world passive components. .

Bruce is a buddy, I was quite flattered when he visited us and insisted on a one on one meeting. We became a beta site for AP as we were for Tek in general. The AP is a reference measurement system, extrapolating the absurdly low distortions of generally good caps and resistors to audibility in consumer DAC's, etc. is silly. Out of the bin SMT resistors and capacitors used in reference designs had immeasurable distortion on any test with the latest AP. And yes I did tests that included self heating, yadda, yadda.
 

Beave

Major Contributor
Joined
May 10, 2020
Messages
1,382
Likes
2,989
^Along those lines, we used to test several audio and video parametrics with the DUT in an 'oven,' (a temperature & humidity controlled small chamber about the size of an actual oven, with small holes in the side to allow cabling in and out) in which we could vary the temperature and humidity. We could test over a 100 degree temp range with humidity from nearly 0% up to near 100%.

We had requirements on products to be *functional* over certain very wide temp/humidity ranges, and other requirements that the product continued to meet parametric specs (freq resp, thd, snr, etc) over narrower ranges. For example (just making up numbers), product had to be functional from 40 deg F to 120 deg F, and had to meet all parametric specs while operating from 60 deg F to 90 deg F.

Of course, if the chamber temperature was set to x degrees, the actual temperature of some components on the board would be higher than x.
 

Wombat

Master Contributor
Joined
Nov 5, 2017
Messages
6,722
Likes
6,463
Location
Australia
I have no technical background in any of this. It seems to me we should be able to measure the quality of these devices.

But it just seems to me that measuring a speaker using a frequency sweep doesn't measure everything we ask a speaker to do. It's a physical device playing many frequencies at the same time.

Audi diesels measured well, but in the real world they didn't perform in the same way.

why isn't this a potential problems with the frequency sweep measurements that seem to be the standard today?

TIA!

Re Audi. Are you referring to the fraudulant different software mapping for govt. pollution testing vs that for general road use?
 
Last edited:

Sawdust123

Member
Joined
May 3, 2019
Messages
49
Likes
160
We had requirements on products to be *functional* over certain very wide temp/humidity ranges, and other requirements that the product continued to meet parametric specs (freq resp, thd, snr, etc) over narrower ranges. For example (just making up numbers), product had to be functional from 40 deg F to 120 deg F, and had to meet all parametric specs while operating from 60 deg F to 90 deg F.
I started my career designing mil-spec microwave components (mostly LNAs and SSPAs for radar). Temperature cycling was -55c to +125c. We also had to do shock and vibe testing. You see also sorts of interesting things happen to circuits, especially naval circuits that had to withstand 5000G (yes 5000) shocks (simulated torpedo impact). We also had to design for some pretty high MTBFs calculated according to MIL-HDBK 217. This really gave me an appreciation of good design techniques and the value in derating components. Components are a lot more forgiving when not being pushed to their extremes.
 

ctakim

Active Member
Forum Donor
Joined
Jan 3, 2021
Messages
148
Likes
195
Location
Menlo Park, CA
Hmmm....

I wouldn't agree.

Placebo effects are sensed.
I think we have a difference in semantics. I would define sensed as being triggered by sound waves impacting the tympanic membrane ultimately leading to stimulation of the cochlear nerve. The biology of hearing is ultimately physics. Auditory hallucinations are certainly perceived, but not sensed in that they are not triggered by stimuli in the physical world. By my definition, a placebo effect would also be perceived but not sensed. But perhaps I am really splitting hairs (or hair cells) here.
 

solderdude

Grand Contributor
Joined
Jul 21, 2018
Messages
15,988
Likes
36,190
Location
The Neitherlands
In general digital problems. clock drift, bit flips in some byte patterns, beat frequency of close but not locked clocks.
On the analog side maybe. DCDC converters that change the frequency randomly, maybe because of temperature or load variations.
Or because they intentionally do spread spectrum.

Would all show up in FFT as skirting or multiple frequencies or be visible in other types of measurements.
It's about things that are not measurable but audible.
 

Sawdust123

Member
Joined
May 3, 2019
Messages
49
Likes
160
Bruce is a buddy, I was quite flattered when he visited us and insisted on a one on one meeting. We became a beta site for AP as we were for Tek in general. The AP is a reference measurement system, extrapolating the absurdly low distortions of generally good caps and resistors to audibility in consumer DAC's, etc. is silly. Out of the bin SMT resistors and capacitors used in reference designs had immeasurable distortion on any test with the latest AP. And yes I did tests that included self heating, yadda, yadda.
AP added dual FFT measurements about a year (maybe 2) ago. I haven't had a chance to use that function (I have been gone for 4+ years) but had been asking for that function for many years. My interest was waveform comparisons using actual music as the test signal and real world loads. This should reveal and characterize any deviation from an ideal straight-wire-with-gain device.

BTW, Bruce was a big fan of Analog Devices until they announced the discontinuance of a matched pair of BJTs that AP used a lot of (forget the model). Apparently the announcement was made after the foundry shut down the process leaving no chance for large last time buys. He vowed at the time to design out all AD devices in all AP gear and never do business with them again. If I recall correctly AD later reconsidered their decision.
 

jsrtheta

Addicted to Fun and Learning
Joined
May 20, 2018
Messages
947
Likes
1,008
Location
Colorado
A high school band in Wenatchee, Washington, USA, came up with the Covid-19 pandemic safety idea of putting band members in tall, skinny tents for indoor practice/rehearsals. It was a bit cramped for the tuba player...

View attachment 115539

That's a Sousaphone, not a tuba.

Trust me, I know from bitter experience.
 

Katji

Major Contributor
Joined
Sep 26, 2017
Messages
2,990
Likes
2,273
:oops: That's probably the most bizarre thing I've seen in the covid pandemic context. ...I hope it's the most bizarre thing I see today. :D
 

Zog

Active Member
Joined
Mar 13, 2019
Messages
255
Likes
290
Bottom line: by first principles, every signal change that may ever cause audible differences can always be reliably measured (quantified in some way) and exposed. Period.
I am reporting you to the police. The expression 'Period' after a 'period' or, in more common language - a 'full stop' is a redundancy. That is to say you have entered the same expression twice in a row. (I have just done a redundancy). More important is that the effect of sense (an expression used by Umberto Eco) is that one is using an 'intensifier'. That is to say a word like 'F...' or the use of the word 'very', or the use of an exclamation mark. In my humble opinion they should never be used. At least not in such an august forum as ASR.
 

StefaanE

Addicted to Fun and Learning
Forum Donor
Joined
May 12, 2020
Messages
528
Likes
930
Location
Harlange, Luxembourg
I am reporting you to the police. The expression 'Period' after a 'period' or, in more common language - a 'full stop' is a redundancy. That is to say you have entered the same expression twice in a row. (I have just done a redundancy). More important is that the effect of sense (an expression used by Umberto Eco) is that one is using an 'intensifier'. That is to say a word like 'F...' or the use of the word 'very', or the use of an exclamation mark. In my humble opinion they should never be used. At least not in such an august forum as ASR.
This is the police. Please give us your email address so we can send you the forms to fill out to register your complaint. In triplicate, and with a biro. Blue, not black or red.
 

Blumlein 88

Grand Contributor
Forum Donor
Joined
Feb 23, 2016
Messages
20,685
Likes
37,398
This is the police. Please give us your email address so we can send you the forms to fill out to register your complaint. In triplicate, and with a biro. Blue, not black or red.
I would think only this ink should be official. Using a proper fountain pen, not some mass produced biro.

1614587218591.png
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
21,529
Likes
21,802
Location
Canada
^Along those lines, we used to test several audio and video parametrics with the DUT in an 'oven,' (a temperature & humidity controlled small chamber about the size of an actual oven, with small holes in the side to allow cabling in and out) in which we could vary the temperature and humidity. We could test over a 100 degree temp range with humidity from nearly 0% up to near 100%.

We had requirements on products to be *functional* over certain very wide temp/humidity ranges, and other requirements that the product continued to meet parametric specs (freq resp, thd, snr, etc) over narrower ranges. For example (just making up numbers), product had to be functional from 40 deg F to 120 deg F, and had to meet all parametric specs while operating from 60 deg F to 90 deg F.

Of course, if the chamber temperature was set to x degrees, the actual temperature of some components on the board would be higher than x.
Seeing as we are on the topic of baking ovens. :D I worked as a QA/QC tech for a downhole tool company. We made tools that go downhole when drilling or monitoring petroleum wells or any other deep well needing monitoring. They measured up to a average of ~175C, 20KPSI plus torque and strain. We would mount a few hundred ICs on PCBs and mount wires for test on each and then put them in the oven with the leads protruding out for a test at high temperature. The qualifying rate for them to operate at ~170C (338F) and up to ~184C (363F) was not very high and it varied from batch to batch but there where good ones in there and they commanded a high price. It was my job to analyze tools that where returned for service or repair. Some of them looked like they had been stuck in a volcano and baked there. The environment downhole is corrosive and harsh and so the casings where machined in house from hastelloy which is extremely prone to galling and is very difficult to machine without proper tooling and experience. Never in my mind had I thought a IC could operate up to 184C but they can and do after qualifying the good ones.
 
Last edited:
Top Bottom