i think it is very likely that within certain frequency ranges we are more likely to hear distortion than in others. this type of effect might arise from an increased cortical representation for certain frequency bands. there are several publications showing that for the sense of "touch", increased cortical representation correlates with increased spatial acuity. it would not be unreasonable to think that something analogous happens with hearing.
at the level of the ear i don't think there is any evidence for a frequency preference (over frequencies we can hear). the ear is actually performing a mechanical FFT on the incoming sound waves.
one interesting idea, however, is that there is cortical feedback to the ear whereby activation of hair cells actually vibrates the same membrane that is excited (indirectly) by changes in air pressure. This might serve to amplify incoming sounds, perhaps at specific frequencies. the activation of these hair cells can be heard in the form of otoacoustic emissions.
here is an example of an abnormally loud otoacoustic emission from a dog
at the level of the ear i don't think there is any evidence for a frequency preference (over frequencies we can hear). the ear is actually performing a mechanical FFT on the incoming sound waves.
one interesting idea, however, is that there is cortical feedback to the ear whereby activation of hair cells actually vibrates the same membrane that is excited (indirectly) by changes in air pressure. This might serve to amplify incoming sounds, perhaps at specific frequencies. the activation of these hair cells can be heard in the form of otoacoustic emissions.
here is an example of an abnormally loud otoacoustic emission from a dog
Lineup,
all things that make a sound has a fundamental and harmonics.
All sounds have an arrival time at your ear, some direct and indirect. There are a variety of ambient noises present, people animals, cars, toilet flushing. Sounds mix with each other in your ear, because your ear is not linear and it causes more distortions.
Your brain processes these sounds adding and subtracting things from it that you have memorized, or some emotionally related things.
I do not think it is something one can easily solve.
There is no perfect amplifier, speaker, listening room, ears, and brain.
Nor is the ambient ever the same. Even air temperature has an effect on the propagation of the sound. Just moving your head from side to side makes things sound different.
By swallowing spit or yawing changes what you hear because the nose, throat and ear channels share some air pressure.
I do not think that there is anybody that could put it down as simply the harmonic content of an amplifier or the particular topology or magical components creating some sweet sound.
In my opinion we are fooling ourselves most of the time and it is our brains telling us this is nice and that is not. It is like taste, when it is absolutely neutral is it almost sweet or almost bitter?
Because of our analytical nature we are trying to solve a very complex equation with endless number of variables expecting to reduce this to a simple answer. In five decades I have been trying and never came close.
So for us hi-fi buffs, we try and eliminate as much as we can by using a wire with gain, design transducers with no inertia, zero mass, infinite compliance and absolutely rigid. We connect all these things together with oxygen free, super conductors.
Then we go and buy a mediocre recording of Madonna with an electronically generated orchestra and chorus wondering if this is how it should sound. I guess it is.
all things that make a sound has a fundamental and harmonics.
All sounds have an arrival time at your ear, some direct and indirect. There are a variety of ambient noises present, people animals, cars, toilet flushing. Sounds mix with each other in your ear, because your ear is not linear and it causes more distortions.
Your brain processes these sounds adding and subtracting things from it that you have memorized, or some emotionally related things.
I do not think it is something one can easily solve.
There is no perfect amplifier, speaker, listening room, ears, and brain.
Nor is the ambient ever the same. Even air temperature has an effect on the propagation of the sound. Just moving your head from side to side makes things sound different.
By swallowing spit or yawing changes what you hear because the nose, throat and ear channels share some air pressure.
I do not think that there is anybody that could put it down as simply the harmonic content of an amplifier or the particular topology or magical components creating some sweet sound.
In my opinion we are fooling ourselves most of the time and it is our brains telling us this is nice and that is not. It is like taste, when it is absolutely neutral is it almost sweet or almost bitter?
Because of our analytical nature we are trying to solve a very complex equation with endless number of variables expecting to reduce this to a simple answer. In five decades I have been trying and never came close.
So for us hi-fi buffs, we try and eliminate as much as we can by using a wire with gain, design transducers with no inertia, zero mass, infinite compliance and absolutely rigid. We connect all these things together with oxygen free, super conductors.
Then we go and buy a mediocre recording of Madonna with an electronically generated orchestra and chorus wondering if this is how it should sound. I guess it is.
Nico Ras said:
Nico,
you are probably very right.
We can only do our best to make amplifier + loudspeaker be:
input = output
There are small adjustments we can achieve by trimming our audio system.
But in the end, the actual outcome is very difficult to predict.
There are many more things involved than only Harmonics Spectrum
and other forms of measurable Intermodulation, Delay, Phase and such.
Will this stop me from trying to find my solutions to how to make amplifier+speaker 'sound right'??
... The Answer is 100% sure ... Nooooooo!!!!!
Nico,
nice post, however I must not sway away from my analretentive, perfectionistic, technocrate personality and ask..
did you never manage to make an amp that was transparent?
AFAIK there are several pieces of gear that actually is transparent out there and that is my goal with all transmissionlinks. I view mic's and speakers as encoding/decoding devices so it's not as easy to specify what they should do since (IMO) it depends on the situation and what you want to achieve..
/Peter
nice post, however I must not sway away from my analretentive, perfectionistic, technocrate personality and ask..
did you never manage to make an amp that was transparent?
AFAIK there are several pieces of gear that actually is transparent out there and that is my goal with all transmissionlinks. I view mic's and speakers as encoding/decoding devices so it's not as easy to specify what they should do since (IMO) it depends on the situation and what you want to achieve..
/Peter
I find Nelson Pass shines some interesting light onto these Harmonics issues in his paper.
He does not present to us a some final solution. He admits there are things we still have to know more about.
He is a person of long time experience. He's got a gathered knowledge, not only from his own observations, but from many audio people he has met & talked with during his life in Audio.
Furthermore, he is a person that likes to investigate using meaurable data. Not only use his subjective opinions/observations.
This makes him, in my opinion, a person well worth listening to
Nelson Pass - Distortion & Negative Feedback - full article
Pan said:
Hi Peter,
we came close to doing this, but it was a paying contract. Took seven months and 9 engineers as well as cost the customer a fortune. It was a challenge to design to a written technical specification, but it can be done. Whether this was musical or not is anybodies guess.
Distortion was nothing, slew rate was phenomenal, frequency response DC to daylight.
What did it sound like. It was very nice, I guess knowing that you are listening to everything else making up the system.
It still did not make anything perfect neither more enjoyable nor better than the next system. It did not blow us away.
It sounded different, that is all.
I would say that instead of designing amps and speakers and things one should rather design the gadget that hooks into your brain directly so all the junk can be eliminated and you can experience the pure performance exactly as it happened.
This may not be as far fetched as it sounds. In Star Trek they had communicators, this was far fetched. Less that 20 years later we have cellphones which would put any communicator to shame.
Peter I think everyone in this forum are seeking musical nirvanna but never will and that is what makes it fun. Look at Lineups comment. If and when you reach it, what will you be doing next, build model trains? No chance you will die of boredom.
Kind regards
Nico
worse that gambling or alcohol or even smoking.
i thought that article by nelson pass was fantastic.
his keen rational approach shines a bright light on the darkness that audiophiles seem to inhabit.
i find it painfully ironic that the thread that article was originally posted in is but a few pages long while threads like: "is my amplifier blameless" and "do cables make a difference" are too long to read (likely did not get the titles exactly right but i am sure most of us here know the threads i am referencing)
creating an amplifier that accurately recreates (differences are inaudible) the original signal is well within reach (may already be here - just not the amps i build). the variables are not overwhelming and their individual contribution and interactions can be understood.
lastly, there is no reason to believe that people perceive sound differently. listening skills can certainly be honed, just like any other skill, but generally speaking people hear and see the same things.
his keen rational approach shines a bright light on the darkness that audiophiles seem to inhabit.
i find it painfully ironic that the thread that article was originally posted in is but a few pages long while threads like: "is my amplifier blameless" and "do cables make a difference" are too long to read (likely did not get the titles exactly right but i am sure most of us here know the threads i am referencing)
creating an amplifier that accurately recreates (differences are inaudible) the original signal is well within reach (may already be here - just not the amps i build). the variables are not overwhelming and their individual contribution and interactions can be understood.
lastly, there is no reason to believe that people perceive sound differently. listening skills can certainly be honed, just like any other skill, but generally speaking people hear and see the same things.
I would like to ask a question to all here. Who has become addicted to simulators.
I admit I have since 1996. Is this a general trend or am I just loosing touch with life.
If someone did not tell me about the economic crisis that faces the world it would have passed without me knowing of it.
I admit I have since 1996. Is this a general trend or am I just loosing touch with life.
If someone did not tell me about the economic crisis that faces the world it would have passed without me knowing of it.
I have something close (no 3rd 5th etc.) It is a plus for
FLAC or the best HQ mp3 but I notice a very good amp
will bring out the deficiencies of a poorly encoded source
I can now hear the "swishyness" in all its glory on
some of the 128kbs garbage Mp3's on my new amp.
(too accurate)
They are more pronounced on this amp than my "blameless"
or DX (bootstrapped) topology amps.
I just hit that level.. not yet addicted, but it is VERY useful.
That ends when you hook the real thing to your speakers,
then one must go "destroyer X mode" (with soldering iron) change Cdom or other comp., degen stages for different
currents, etc. stand back , crank it up.. assess, try again.
All this should be tried first in the model to make sure you
don't end up with a smoking mess.
OS
okapi said:
Let's make Nelson Pass thread longer.And focus on matters his article raise. And share our findinds/thinkings:
Pass Labs >Distortion and Negative Feedback
okapi,
I see you might be working on some utility/software for using PC for Distortions Measurements, Topic:
THD measurement - how to?
What setup you have to measure?
Nico Ras said:I would like to ask a question to all here. Who has become addicted to simulators.
I admit I have since 1996. Is this a general trend or am I just loosing touch with life.
If someone did not tell me about the economic crisis that faces the world it would have passed without me knowing of it.
Nico, you are not the only ...
Far from. And you are in very good company.
Some of the best amplifier designers in this world are frequently spicing things up ....
I admit! I am addicted. For like 2 years now.
Simulations have saved me lots and lots of money. And burnt equipment.
Of course I would like to try to build my best Spice Created Amplifiers.
But currently, I am not in the situation to do this.
Neither my money nor my room for working space does allow me to do this practically.
I do not think my amplifiers are bad. Just because I did not build them. There is no logic into state this.
-> And our dreams, hopes & ideas are more worth, than harsch, cruel reality and the fullfillment of our dreams <-
I love my spice working board
New ideas are born, tested and refined.
A part of my day. For good or for bad. Anyway, this is the fact.
Lineup
Because the wife is NOT an audiophile and downloads garbage
My sytem is almost commercial in the confines of the
household and is used by all.
Quality ranges all the way from 320kbs CBR /FLAC(most of it) to
the wifes soundtracks and music video's (the garbage) , so
I am "exposed" to some quality issues at times.
OS
Hi Lineup,
distortion measurement is not that complex and one may achieve it quite simple with analogue stuff.
Firstly, the measurement is based on ratios referred to as SINAD (Signal Noise and Distortion) compared to NAD (Noise and Distortion).
For making this measurment you need two filters at the frequency of interest. Unfortunately you have to design filters for every frequency of interest say 1 kHz, 10 kHz and 100 Hz. these filters has to have extremely hi Q and is best done with passive components that does not add any distortion of their own.
You do not have to worry about, levels, power or the like you will compare one unit of output to one unit of noise and distortion and from there a ratio which is converted either into a percentage or a dB ratio.
Unless the distortion is very very low, a simple audio mili-volt meter or oscilloscope can be used.
Do you want to know more?
Nico
distortion measurement is not that complex and one may achieve it quite simple with analogue stuff.
Firstly, the measurement is based on ratios referred to as SINAD (Signal Noise and Distortion) compared to NAD (Noise and Distortion).
For making this measurment you need two filters at the frequency of interest. Unfortunately you have to design filters for every frequency of interest say 1 kHz, 10 kHz and 100 Hz. these filters has to have extremely hi Q and is best done with passive components that does not add any distortion of their own.
You do not have to worry about, levels, power or the like you will compare one unit of output to one unit of noise and distortion and from there a ratio which is converted either into a percentage or a dB ratio.
Unless the distortion is very very low, a simple audio mili-volt meter or oscilloscope can be used.
Do you want to know more?
Nico
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