Yes, you can have asymmetric waveforms, BUT you have to have generate the DC component IF you take a symmetric waveform and distort it to be asymmetric. That is what happens in power lines, as best that I can tell, and we are talking about a POWER LINE in the first place. Get real guys, note what we are discussing, rather than trying to find exceptions.
I've conjectured that another one of the reasons people claim to like second harmonic distortion is that the low-frequency term ("d.c.", but always highpassed out in any real electroacoustic situation) gives a certain cue to the auditory system that something "big" is going on.
A project that awaits board layout is a voice coil temperature measurement system for Marshall Buck and his company Psychotechnology. Marshall had an experimental system some years back when he worked for Harman's Applied Technology division. His approach, to pick out the d.c. offset from a d.c. probe current while a.c.-coupling the main signal to do the primary heating of the driver under test, sounds straightforward enough. But if you consider the requirements on the filter and the need for stringent bandlimiting at low frequencies of the test signal, and the desire to have the d.c. probe current be fairly small, it turns out to be quite a measurement challenge. 5kW into 8 ohms while looking at an 80mV offset is really a needle in a haystack. In particular, if there is much even-harmonic distortion the d.c. component will produce a significant error. Now one can "chop" the probe signal, or reverse its polarity periodically. But I found, after a good deal of effort and experiment, a configuration for the lowpass filter chain that had low-enough distortion.
A project that awaits board layout is a voice coil temperature measurement system for Marshall Buck and his company Psychotechnology. Marshall had an experimental system some years back when he worked for Harman's Applied Technology division. His approach, to pick out the d.c. offset from a d.c. probe current while a.c.-coupling the main signal to do the primary heating of the driver under test, sounds straightforward enough. But if you consider the requirements on the filter and the need for stringent bandlimiting at low frequencies of the test signal, and the desire to have the d.c. probe current be fairly small, it turns out to be quite a measurement challenge. 5kW into 8 ohms while looking at an 80mV offset is really a needle in a haystack. In particular, if there is much even-harmonic distortion the d.c. component will produce a significant error. Now one can "chop" the probe signal, or reverse its polarity periodically. But I found, after a good deal of effort and experiment, a configuration for the lowpass filter chain that had low-enough distortion.
Some of the many Bob Pease “Floobydust” articles.
What's All This FLOOBYDUST Stuff, Anyhow?-part 5 | Archive content from Electronic Design
What's All This Floobydust Stuff, Anyhow? (1993) | Analog content from Electronic Design
What's All This Floobydust Stuff, Anyhow? (Part 6) | Archive content from Electronic Design
What's All This Floobydust Stuff, Anyhow? (Part 11) | Products content from Electronic Design
What's All This Floobydust Stuff, Anyhow? (Part 9) | Electromechanical content from Electronic Design
What's All This Floobydust Stuff, Anyhow? (Part 10) | Boards content from Electronic Design
I think we've started arguing over trivia, diodes clipping will make DC let's just say this is a sine at 0 frequency. My real complaint is over the statement that music is asymmetric (has DC) so sine wave testing is ineffective.
yep, more misdirection...
a statement about music tones/overtones containing DC morphed into an assertion about mains including it. of course it does, when rectifiers clip/fail or when switchmode supplies without power factor correction take from the positive going swing of all 3 phases, cause harmonic distortion. etc.
2 completely different things, yet one factor used to explain another.
a statement about music tones/overtones containing DC morphed into an assertion about mains including it. of course it does, when rectifiers clip/fail or when switchmode supplies without power factor correction take from the positive going swing of all 3 phases, cause harmonic distortion. etc.
2 completely different things, yet one factor used to explain another.
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Let's get real. A 50-60 Hz sine wave generated from the power company is free of 2'nd harmonic distortion as much as possible. WHY? Because the DC component would saturate the power transformers in the path, very easily.
This topic first occurred when the measurements made by AMES was critiqued. This is the nature of DC on the mains which is a REAL PROBLEM in many AC systems.
This topic first occurred when the measurements made by AMES was critiqued. This is the nature of DC on the mains which is a REAL PROBLEM in many AC systems.
No one has said that. Thats your reading of it. When I used the term Dc it was in reference to an average level at a short time period (not infinite time) such as a transient's average level. Everything you has addressed is off base and not about finding a model in electronic terms which describes the thd found in some caps... some more or less than others. All cap models ignore the non-linear portion of the part. Can you describe the model or make up a model that predicts the thd of an electrolytic or a ceramic (non npo)? That is what we would like to see.... a non-linear model from you that matches a measurement. That would help a lot more than going over how everything can be explained with sine wave combinations. yes. but so what? We want a model that predicts thd or any other form of distortion and backed up by measurment. Thats all we are looking for. Thx-RNMarsh
Richard, I guess you missed it, it was said and not for the first time. you seem to be on a completely different tack....its an old chestnut that gets pulled out whenever in depth testing with instruments does not match miraculous claims.
it was made in reference to the BQP, asking SY if he could repeat the testing with music signals or multitone testing that is more like 'real music' because 'real music' often has an asymmetric waveform with a DC component. Scott's post was illustrating that you can add sinewaves any way you like and still not get any DC. then there was a misdirect pointing at AC mains suply having DC, which is caused by DC being spilled back into the mains, or energy being given/taken asymmetrically from the AC, NOT the addition of more sinewaves.
it was made in reference to the BQP, asking SY if he could repeat the testing with music signals or multitone testing that is more like 'real music' because 'real music' often has an asymmetric waveform with a DC component. Scott's post was illustrating that you can add sinewaves any way you like and still not get any DC. then there was a misdirect pointing at AC mains suply having DC, which is caused by DC being spilled back into the mains, or energy being given/taken asymmetrically from the AC, NOT the addition of more sinewaves.
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Anybody Willng ?...
Back to the BQP......
Is there any similar product available ?.
There are numerous reviews of the differing forms (models) of BQP, all state that the BQP causes subjective difference, most reviews are positive, and at least one review is negative in particular context.
I have spoken directly to an Australian speaker manufacturer who incorporates BQP's into his loudspeakers and his opinion is entirely positive, and his subjective description fully in line with what other reviewers and users are saying but added that subjective distortion is also reduced.
So far we have no test results that confirm what subjective evaluations are stating.
Do we have any BQP users present here who are willing to do a 'Diffmaker' type test using music signals and perhaps some other 'to be defined' steady state signal, in order to differentiate signal changes ?.
Do we have any BQP users present here who are willing to present a review of the subjective effects on their systems ?.
Regardless of the BS explanations presented on the Bybee website, it does seem that there is 'something' interesting going on, and 'expectation' factor of users/reviewers is not a factor.
SY, I understand that your steady state testing methods whilst entirely correct have not revealed behaviour that would account for the subjective findings.....this leads me to the conclusion that standard steady state test methodology is not appropriate to analyse the behaviour of this circuit element.
We have good brains around here with good test gear that ought to be able to discriminate and then analyse what BQP's are doing.....anybody ?.
Thanks, Dan.
Back to the BQP......
Is there any similar product available ?.
There are numerous reviews of the differing forms (models) of BQP, all state that the BQP causes subjective difference, most reviews are positive, and at least one review is negative in particular context.
I have spoken directly to an Australian speaker manufacturer who incorporates BQP's into his loudspeakers and his opinion is entirely positive, and his subjective description fully in line with what other reviewers and users are saying but added that subjective distortion is also reduced.
So far we have no test results that confirm what subjective evaluations are stating.
Do we have any BQP users present here who are willing to do a 'Diffmaker' type test using music signals and perhaps some other 'to be defined' steady state signal, in order to differentiate signal changes ?.
Do we have any BQP users present here who are willing to present a review of the subjective effects on their systems ?.
Regardless of the BS explanations presented on the Bybee website, it does seem that there is 'something' interesting going on, and 'expectation' factor of users/reviewers is not a factor.
SY, I understand that your steady state testing methods whilst entirely correct have not revealed behaviour that would account for the subjective findings.....this leads me to the conclusion that standard steady state test methodology is not appropriate to analyse the behaviour of this circuit element.
John's passage above confirms that steady state testing is inappropriate.
We have good brains around here with good test gear that ought to be able to discriminate and then analyse what BQP's are doing.....anybody ?.
Thanks, Dan.
Max how exactly would one reduce 1/f noise passively without effecting a signal?
edit: sorry I think i've misunderstood your post. I thought SY said hed done multitone? I fail to see how substituting music will make any difference and gather the testing SY did was far more extensive than mentioned here. just look at the thing, do you honestly think there is magic inside?
the marketing is a bunch of unadulterated subterfuge and lies, do you really think if there was a technical reason it 'works' that it would not have been big scientific news?
edit: sorry I think i've misunderstood your post. I thought SY said hed done multitone? I fail to see how substituting music will make any difference and gather the testing SY did was far more extensive than mentioned here. just look at the thing, do you honestly think there is magic inside?
the marketing is a bunch of unadulterated subterfuge and lies, do you really think if there was a technical reason it 'works' that it would not have been big scientific news?
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That Is The Question...
That said, the it seems that the BQP device removes/alters noise from the composite signal (original signal + noises) and leaves a resultant that is closer to the original signal....that's what I glean from the reviews.
I have no commercial interest in these devices, however I am intensely interested in their behavior and real explanation.
Their price/value.....that's another subject altogether, and not relevant in this discussion.
Dan.
I have no idea !.
That said, the it seems that the BQP device removes/alters noise from the composite signal (original signal + noises) and leaves a resultant that is closer to the original signal....that's what I glean from the reviews.
I have no commercial interest in these devices, however I am intensely interested in their behavior and real explanation.
Their price/value.....that's another subject altogether, and not relevant in this discussion.
Dan.
Qusp,
Since you are in the same country as Mad Max, could go over there and bop him on the head please! Max. go ahead an buy some of these things if you believe they work and tell us all about it! There's a bridge in New York I'll sell you! Can we move on to a serious subject now.
Soctt,
I was told recently that in the power amplifier chips (3886) from National and most others that the internal NFB loop is bypassing the input LTP section of the chip and that section is not included in the feedback loop. Is that true and if so why do they do that?
Since you are in the same country as Mad Max, could go over there and bop him on the head please! Max. go ahead an buy some of these things if you believe they work and tell us all about it! There's a bridge in New York I'll sell you! Can we move on to a serious subject now.
Soctt,
I was told recently that in the power amplifier chips (3886) from National and most others that the internal NFB loop is bypassing the input LTP section of the chip and that section is not included in the feedback loop. Is that true and if so why do they do that?
fair enough Dan, however I do think SY has done enough, as you hint at yourself. i'm not insinuating you have any interest other than intellectual. I dont think there is anything there and I think weve spent enough time on it. There will always be something else the testing has 'missed' as long as it doesnt match subjective reports...
lol @ Kindhornman, MAX is about 4400km away... but I understand the sentiment
lol @ Kindhornman, MAX is about 4400km away... but I understand the sentiment
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It's already been done. That seems to be hard for you to understand.
It's a fraud. That also seems to be hard for you to understand. Many frauds are widely believed- that's unfortunately the reality of human belief.
Dan, at the moment your comments seem to be the only ones attempting to advance understanding of the situation ...
The highlighted comment is where the subjectivists and objectivists butt heads - the latter are certain that what they are measuring is a load of rubbish and a scam anyway, so they won't bother themselves doing a more thorough investigation. The poor subjectivists "know" there's something going on, but haven't the technical background or equipment to organise proper experiments, taking into account the time dependent aspect of many of the behaviours. So everyone gets nowhere, and the circus continues ...
Frank
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