A few factual errors of your own... but I will let that slide.
No, Richard Small was not Australian, but he was at Sydney University and yes, I am in Sydney too. I knew Small when he was here. He was actually from California but came to Sydney and took Thiele's work (1961) and enlarged upon it. I can tell you that Small disliked to the idea that amplifiers had "damping Factor" and in fact it angered him. He let me know precisely what he thought about it, I still hear his voice in my head.
An externally hosted image should be here but it was not working when we last tested it.
This proves that an amplifier with zero output Z will not erode the electrical damping, but if it has even the slightest output impedance, Qes will erode.
Hence Small made the argument that an amplifier can only making damping worse and not better.
A solid argument!
It is interesting that it is also in Sydney that more work is being done, and those who are too quick to judge can end up on the wrong side of history.
Yes, the status quo always seems to lead to a rigid mindset.
BTW, we are talking about something measurable. Reduction of distortion, the "Holy Grail" of Hi-Fi (sad to hear about Terry Jones).
And no, I am not going to let it out all here and it is ongoing. This is not the place, you can understand that. Yes, several guys connected with universities are involved.
Cheers, Joe
Joe, I've been at the center of controversy too. I have an amp that simulates like this in its current iteration
under any load and I had a hard time disproving the results in real life tests so I came here to get some help with verification. As you can probably understand I don't really want to share the schematic without some sort of protection first especially after all the time and money I've put into it even though I really shouldn't considering my life situation. That did not go over well and I was mocked continuously in a very long thread.
The difference between me and you is I don't care about the opinions of internet people. I smile and grin and try to eek out as much constructive feedback as possible before it gets nonconstructive beyond hope and I peace out. You gotta let things slide man. Until you come back with some concrete data people in this forum don't really respond well to controversy. At least you have people to help you on your endeavor, I've been struggling for years on my own with no one to help and barely enough money to live. I finally got an offer from a fellow member to assist me with third party performance verification and some potential licencing deals, ect but I gotta travel cross country to meet him. Hopefully that works out because I'm reaching the end of the road of what I can do with my means.
under any load and I had a hard time disproving the results in real life tests so I came here to get some help with verification. As you can probably understand I don't really want to share the schematic without some sort of protection first especially after all the time and money I've put into it even though I really shouldn't considering my life situation. That did not go over well and I was mocked continuously in a very long thread.
The difference between me and you is I don't care about the opinions of internet people. I smile and grin and try to eek out as much constructive feedback as possible before it gets nonconstructive beyond hope and I peace out. You gotta let things slide man. Until you come back with some concrete data people in this forum don't really respond well to controversy. At least you have people to help you on your endeavor, I've been struggling for years on my own with no one to help and barely enough money to live. I finally got an offer from a fellow member to assist me with third party performance verification and some potential licencing deals, ect but I gotta travel cross country to meet him. Hopefully that works out because I'm reaching the end of the road of what I can do with my means.
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I was there!
I might even have a video of Tom's presentation? I know because all the lectures at ETF06 were videoed. I should know, I was the videoer. Is that a real word?
It is a topic I am interested in, but Menno Vanderveen has already requisitioned the "Super Triode" moniker as his.
Here is another Triode circuit, not "Super Triode" and this one is called "Beyond Triode" - I posted it earlier, here it is again:
Cheers, Joe
PS: Would anybody we interested in watching Tom's Pentode Strapped Triode presentation?
A few factual errors of your own... but I will let that slide.
Why let it slide? If you have something to say, say it. I live to learn.
All good fortune,
Chris
Current in the voice coil corresponds to force (with fixed B field), and force would correspond to air pressure IF the cone and voice coil had no mass AND the speaker suspension were zero force. So the current controls the sum of the three terms.
Voltage on the voice coil corresponds to velocity (with fixed B field) except voice coil resistance and leakage inductance subtracts out some Voltage.
The signal coming in depends on the type of initial transducer as well.
Then f = ma, and velocity = integral of acceleration. Leading to Volts as the integral of current in the speaker. And then the integral of sine is cosine, for any sine wave signal component, so Volts control versus I current control will just be causing supposedly inaudible phase shifts for each sine wave component. (ignoring the parasitic components mentioned: mass, suspension, resistance ..)
Volts control will react to back pressure to keep the velocity controlled. While current control will not. So the speaker enclosure will have large effects on current controlled speaker performance.
With so many parasitic speaker parameters interfering, an amplifier output impedance control, that allows adjustment for best sound from the speaker, would seem useful to me.
Or use a dual voice coil speaker to get direct Volts/velocity feedback from the extra winding (and could differentiate that to get acceleration/pressure feedback for a current control case)
Voltage on the voice coil corresponds to velocity (with fixed B field) except voice coil resistance and leakage inductance subtracts out some Voltage.
The signal coming in depends on the type of initial transducer as well.
Then f = ma, and velocity = integral of acceleration. Leading to Volts as the integral of current in the speaker. And then the integral of sine is cosine, for any sine wave signal component, so Volts control versus I current control will just be causing supposedly inaudible phase shifts for each sine wave component. (ignoring the parasitic components mentioned: mass, suspension, resistance ..)
Volts control will react to back pressure to keep the velocity controlled. While current control will not. So the speaker enclosure will have large effects on current controlled speaker performance.
With so many parasitic speaker parameters interfering, an amplifier output impedance control, that allows adjustment for best sound from the speaker, would seem useful to me.
Or use a dual voice coil speaker to get direct Volts/velocity feedback from the extra winding (and could differentiate that to get acceleration/pressure feedback for a current control case)
Compared to a shorted speaker.. For an open speaker the Zo only increases damping. Which is the correct point of view and why?
My apologies, I probably chose the wrong words.
But please do not resume to lecture me on the basis of something I said and you did not fully understand, please.
Yes, I have heard that argument many times and it is flawed.
But I am surprised that you would argue against somebody as august as Richard H. Small who wrote the book. Would you like to email him?
Why is it a flawed argument?
Simple, you are arguing from the wrong default position. Also, if you short the voice coil you have the damping of the driver as the same as if you had it connected to an amplifier with a source Z of zero. So if the Q = 1 (assuming a sealed box for simplicity), then shortening the terminals you will have the damping of Q = 1.
What happens when you open the terminals, you end up with no damping and typically on mechanical damping left, so it will like be Q = 3 or higher.
Now connect it to an amplifier, and let is say it has an output impedance of 0.5 Ohm and the DC resistance of the voice coil is 5 Ohm (typically an 8 Ohm driver is 5-6 Ohm), what will be the Q then?
Qes = (2Pi*Fs*Mms*Re)/Bl^2
In this equation, if Re is increased from 5 to 5.5, then Qes is increased 10%.
So the answer would be Q = 1.1 (it will actually be slightly less than that due to Qms component).
So Small rightly argued that an amplifier can only make damping worse, not better.
The only way to change that, and not really applicable here, is to generate a negative impedance (a la motional feedback).
So there you are. The amplifier does not add damping, it can only maximise damping.
Cheers, Joe
PS: Small also argued, to my surprise, that adding series resistance to an overdamped driver was legitimate.
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You mean moi, lack of comprehension of the basics is in your court. What a joke.
EDIT - I just read back in this thread, stunning just stunning.
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I was only asking for context, there can't be an argument without it..
Ok, so speaker is 0.4 and Zo makes it 0.6, is that worse? (context
)
I took your challenge seriously. And I will answer it. The other is the distortion measurement we have also discussed.
Patience usually brings good results.
But please, let us not turn this into another blowtorch session.
Re topic here: What is your position on the 'sound' of tubes?
I was only asking for context, there can't be an argument without it..
Ok, so speaker is 0.4 and Zo makes it 0.6, is that worse? (context
Not sure what the question is?
But what did you think about the explanation given, particularly Small's?
I was there!
I might even have a video of Tom's presentation? I know because all the lectures at ETF06 were videoed. I should know, I was the videoer. Is that a real word?
It is a topic I am interested in, but Menno Vanderveen has already requisitioned the "Super Triode" moniker as his.
Here is another Triode circuit, not "Super Triode" and this one is called "Beyond Triode" - I posted it earlier, here it is again:
Cheers, Joe
PS: Would anybody we interested in watching Tom's Pentode Strapped Triode presentation?
a rose by any other name is still a rose, why not call it O'Schade circa 1930's and be done with it...
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This is why old amplifiers provided output impedance control to get critical damping.
Are you, or Small, saying that modern drivers have a voice coil resistance above the required critical damping resistance already? (probably due to modern high field magnets ) In which case the amplifier output Z would not be able to improve the damping (unless negative Z were provided).
The frequency of the speaker resonance will determine what resistance is required for critical damping, (higher freq. leading to higher Z). So a small enclosure would seem to be amenable to improvement of damping by adjusting the amplifier output Z (above 0 ).
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We should qualify this to say that a smaller enclosure, as else kept equal, gives a higher Qtc. And so requires smaller amplifier output Z.
All good fortune,
Chris
Exactly! Copyright you gotta be kidding!
There appears to be some belief that new, "all singing all dancing" ideas marketed by masses of PR or "who shouts loudest" are essentially new.
NO, it's recycling.
Claiming it's new, fails usually by people who aren't interested in finding out the sheer lack of novelty of these old ideas!
TBH this is a typically internet phenomenon made a quantum leap worse by the mass media and the "social networks", which I term "antisocial networks", pushing deliberate tsunamis of ignorance.
In audio there have been very few real innovators.
I can count Schroeder, Blumlein, Gerzon, and a few others, with a large amount of the donkey work done by the French (IRCAM), and the British (BBC and others).
They provide MONEY, so if you have (think you have) a truly original idea submit it, and go that route.
Even this thing has been done multiple times before and yet again falls down with the usual failures...poor calibration, lack of objectivity, and my pet hate, the arrogant belief that algos can do everything.
I particularly dislike this sort of stuff:-
AND
Here we go again... nothing B & K, nothing industry standard, all done by hearsay.
Dislike again:-
...because complex convolution surround was done by Angelo Farina (It) amongst others with well funded work at York University (UK) years ago.
It's probably claiming to be new, but a rip off of old ideas, eg. Microsoft became masters of it.
It* even has to use the evil sounding AAC (another codec) to get there into surround mode, because basically there's nothing else, yet the BS is tangible when I read the reviews.
I then noted this intelligent critic "right on the money".
If there is anything to be learnt from this whole thread, and the acres of debate,(plus my real head banging with a Russian last week, who claimed to know everything!) it's probably been done before, some person in IRCAM or MIT has probably done the research, had the funding and written a scientific paper about it.
+
The author of this thread failed to make note of the use of HD800 as a "measurement device" - which of course it's not,- No1 outright obvious difference between speakers and headphones, the absence of a Schroeder Frequency**, (usually around 200-250hz) and of course the fact headphones produce and image behind the head every time (Prof Schneider), that's about it.
Here we are again Herr Manfred Schroeder. (died 2009).
Author three books and published over 150 articles in his field.
Final quote:-
Guess where the majority of the high energy signal information is?
In the bass LF well below the Schroeder frequency and for which headphones are manifestly quite useless.
A lot of this energy is transferred through the Pinna, which is unique to each individual.
LF response to my mind divides the sheep from the goats.
Somebody to my mind is measuring the wrong thing with the wrong kit.
Again, it's because of way valve amps convert hi impedance voltage to current, particularly around the impedance changes nr resonance v ss low voltage low impedance drive that matter.
There you will hear a difference, but small signal path, as in the above circuits I would hope the differences would be minimal.
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