John Curl's Blowtorch preamplifier part III

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Sample rate is 50MHz, bit depth is 9bit. It is unimportant, because one can make measurement with shorter time base and more Y sensitivity. However, it is unimportant. Nothing interesting is happening there. Time difference between the plots is quite exactly 150ns.

One has to keep in mind that it is only 6m of cable and we speak about audio frequencies, and kilometers of wavelengths, not about nanoseconds and centimeters or meters of signal wavelengths.

Sometimes I have a feeling that many people do not make a difference between seconds, milliseconds, microseconds and nanoseconds or just are unable to transform it into frequencies or wavelengths. They just look at the signal shape without taking into account time axis.

Audio signal is too slow to create any cable reflections or energy storage if cable length is few meters. The only signal that might create cable reflections is HF EMI interference.
You present silly arguments. That is why you do not understand. You are hopelessly lost in the lack of understanding of t-line analysis and it's ABSOLUTE EQUIVALENCY to an LC lumped model.

Since you cannot understand, nor do you even come close to asking the right questions, do this instead..

Model a 20 foot zip as an LC delay line using the per foot parameters, do 20 sections.
Then drive it with a step into an 8 ohm load and then a 150 ohm load.

You will produce the exact same results as a T-line analysis because we are talking about the first 10 microseconds of the response, not audio frequencies. So your "wavelength of audio" argument is just a diversion, nothing more. And not a very good one at that, well beneath you.

This is only the first hurdle you need to understand. The second is human ITD MEASURED response. The third is that a speaker impedance vs frequency is not fully characterized by a single frequency sweep, but has a position, velocity, and acceleration component.

Measurement of the dynamic full spectrum impedance of a speaker while it is being pushed hard by music is the end result, and as I see, two levels of understanding above the level of arguments posed here. Sorry.
Jn
 
That's what I thought. This is where the confusion began for me


Here's some info on ear function Perception Lecture Notes: Frequency Tuning and Pitch Perception
If you read S&M's post fully & followed the link he gave you would have seen that complex sounds i.e. real world sound, not single tone signals, are comprised of temporal fine structure (TFS) which makes up the temporal envelope (ENV) of the sound. We perceive both of these aspects as the full sound envelope. This envelope has various stages, ADSR as you know from your references to music synthesisers. The risetime of the attack portion of this envelope (also called amplitude envelope) is dependent on how fast the build up in amplitudes of the individual TFS frequencies & doesn't involve additional frequencies - this is a different definition & understanding to the basics of FFT decomposition of complex waves - the temporal nature of the waveform is hidden in FFTs in preference for frequency focus.

So, if the risetime of the attack portion of the envelope is fast "The LF HCs will be stimulated quickly with a fast attack and slowly with a slow attack, and therefore will respond differently."

To be clear the TFS defines the spectral structure of the sound, whereas the ENV defines its modulation over time or its temporal structure

I'm sure S&M will correct my misunderstandings if he is still around?
 
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The third is that a speaker impedance vs frequency is not fully characterized by a single frequency sweep, but has a position, velocity, and acceleration component.

Measurement of the dynamic full spectrum impedance of a speaker while it is being pushed hard by music is the end result, and as I see, two levels of understanding above the level of arguments posed here. Sorry.
Jn

Any suggestions for measuring the complex changing impedance of a speaker? My first thought would be to use the same method as measuring instantaneous power (V*I) except (V/I). Simple with modern digital scopes with math channels. However how to capture that in a useful way is the problem.

40 years ago on the first Spectral amp (CPU 1) I managed 1000V/uS. To show it off I added a slew rate meter on the front. Unfortunately even mistracking never got a wiggle from the bargraph until I boosted the gain enormously to more like 1V/uS full scale.
 
Any suggestions for measuring the complex changing impedance of a speaker? My first thought would be to use the same method as measuring instantaneous power (V*I) except (V/I). Simple with modern digital scopes with math channels. However how to capture that in a useful way is the problem.
Not yet. However, that is why I posted the co-wound vc concept. It's another diagnostic tool in the box to play with.

Using zero phase shift resistors for absolute current accuracy, looking at the co-wound coil for the true coil induced voltage...perhaps a dynamic V/I as you mention but with the cowound coil?

The diff between the vc and the co-wound is the exact IR drop, that gives the total system losses both resistive and eddy.

I have given this long thought, and post so that other great minds here can work on it as well.

And there are many great minds here.

Jn
 
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If you read S&M's post fully & followed the link he gave you would have seen that complex sounds i.e. real world sound, not single tone signals, are comprised of temporal fine structure (TFS) which makes up the temporal envelope (ENV) of the sound. We perceive both of these aspects as the full sound envelope. This envelope has various stages, ADSR as you know from your references to music synthesisers. The risetime of the attack portion of this envelope (also called amplitude envelope) is dependent on how fast the build up in amplitudes of the individual TFS frequencies & doesn't involve additional frequencies - this is a different definition & understanding to the basics of FFT decomposition of complex waves - the temporal nature of the waveform is hidden in FFTs in preference for frequency focus.

So, if the risetime of the attack portion of the envelope is fast "The LF HCs will be stimulated quickly with a fast attack and slowly with a slow attack, and therefore will respond differently."

I'm sure S&M will correct my misunderstandings if he is still around?
Long time no see; nice to see to you participating.

While i agree on the importance of processing both (envelope and spectral information) i don´t think that the stimulation of LF HCs will be (very) different if a fast attack occurs.
From the literature it seems that attenuation of the TW is quite effective so that higher frequencies don´t have an impact on the far end of the BM where the low frequency decomposition takes place.
Although the tuning curves for each frequency band show the v-shape when increasing the level there is little expansion above the CF while the broadening (and typical tail) for frequencies below the CF is more pronounced.
So chances are higher that high frequency bands are reacting with neuronal activiy (above the spontaneous rate) if low frequency soundwaves with higher levels are present than the other way round.
 
Scott, if you consider it in simple terms of just one LF frequency & consider how quickly the amplitude of that frequency rises above inaudibility & reaches its full amplitude, then a faster attack (faster amplitude ramp up) will be different in temporal terms than a slow ramp up in amplitude.

This, along with other aspects of the ENV perception will translate into the timbre differences between a plucked bass string & the same string slowly bowed i.e the differences in the amplitude envelope will be perceived
 
SOP, the "Deflection" chapter. I'm not buying.

Is my above description of risetime of the ENV (i.e the Attack portion of a sound) not a case in point of the differences in definition between EE & acoustics or maybe just the difference between those who focus primarily on frequency alone & those who also consider the temporal aspects of the perception of sound or am I just a Fourier denier?
 
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Scott, if you consider it in simple terms of just one LF frequency & consider how quickly the amplitude of that frequency rises above inaudibility & reaches its full amplitude, then a faster attack (faster amplitude ramp up) will be different in temporal terms than a slow ramp up in amplitude.
OK........
This, along with other aspects of the ENV perception will translate into the timbre differences between a plucked bass string & the same string slowly bowed i.e the differences in the amplitude envelope will be perceived
What other aspects of the ENV perception will translate into timbral differences?
 
Then you'd be wrong, look up timbre (again)

Do you have to be so bullish & confrontational? I seem to remember your earlier definition of timbre was very wishy-washy - care to represent it here?

While you are doing that here's the definition from that link S&M gave
"Temporal envelope (ENV) and temporal fine structure (TFS) are changes in the amplitude and frequency of sound perceived by humans over time. These temporal changes are responsible for several aspects of auditory perception, including loudness, pitch and timbre perception and spatial hearing.

Do you mean that I didn't mention the ENV of each harmonic & overtone in my definition of timbre or that I didn't mention TFS also?
 
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