John, I'm confused
Surely only if the measurement system isn't very good (like a cheap soundcard) , if this is the case then the system is not capable of measuring small differences between amps, as its resolving power is smaller than the difference one is trying to measure.
What are you trying to show with the FFT? There are so many frequencies present that they each mask any distortion component of the others. All it seems to be showing is that the frequency response of the twos amps is very slightly different at low frequencies and identical above 80Hz or so.
Phil
Surely only if the measurement system isn't very good (like a cheap soundcard) , if this is the case then the system is not capable of measuring small differences between amps, as its resolving power is smaller than the difference one is trying to measure.
What are you trying to show with the FFT? There are so many frequencies present that they each mask any distortion component of the others. All it seems to be showing is that the frequency response of the twos amps is very slightly different at low frequencies and identical above 80Hz or so.
Phil
One of the files which Nico uploaded was of course phase inverted. So theoretically if I match the levels and put one on top of the other there should be silence but I couldn't achieve this. I agree with Andrew that it's not a meaningful test, since there are many variables involved. When we start changing the levels digitally, this changes the signal.
Suppose we were to take a £10,000 cd player and a £100 cd player and phase inverted one and summed the two. I would bet you could achieve silence and this would show that small differences are being 'masked.' Either that or there is no difference. Actually could someone try this out?
Suppose we were to take a £10,000 cd player and a £100 cd player and phase inverted one and summed the two. I would bet you could achieve silence and this would show that small differences are being 'masked.' Either that or there is no difference. Actually could someone try this out?
the listening test is meaningful.
The comparison if done effectively may show why we hear the two samples as slightly different.
The idea that superimposing graphically two music samples and hoping to see differences due to tiny differences in distortion components is preposterous.
Had we the opportunity to pass the same mono signal through both amps simultaneously and with the outputs of opposite polarity, then we may have been able to record the difference sum. Who developed that test? Was it Baxandall?
I would be interested to see the three samples (amp1,amp2,diff), in sync, and see if, visually, we could see a trend of when the difference signal is not zero, eg on fast rising slopes or on high peak signals or???
The comparison if done effectively may show why we hear the two samples as slightly different.
The idea that superimposing graphically two music samples and hoping to see differences due to tiny differences in distortion components is preposterous.
Had we the opportunity to pass the same mono signal through both amps simultaneously and with the outputs of opposite polarity, then we may have been able to record the difference sum. Who developed that test? Was it Baxandall?
I would be interested to see the three samples (amp1,amp2,diff), in sync, and see if, visually, we could see a trend of when the difference signal is not zero, eg on fast rising slopes or on high peak signals or???
First, what I have been showing (latest in post #919) is not an FFT, it's the frequency response of the entire file. I have mentioned this several times. It is a graphical representation of the sound file, showing the actual level for each frequency. It is difficult to explain and I took it for granted that everyone would understand what it is I'm showing. Anyone who has used a program like Audition will get it.
This is like a fingerprint of the amp and it's very difficult to get 2 to match so closely. Taking in consideration what I had to do to make these files the same level and phase (not to mention polarity) it's amazing they are as close as this.
Soundcard deficiencies are not an issue, the same soundcard was used to record both and the same is used to play them back. If anything, soundcard issues would cause a further rift in the data and make the files even more dissimilar.
I'm afraid I still don't get it. How is it different from taking the FFT of the file which gives the amplitude (and phase) for every frequency for the sample waveform?
I was referring to your comment that you can measure the same thing twice and get different results, not commenting on the files nico had given us.
Anyway as Andrew said it is the listening that matters, lets just build the amp we like the sound of.
Phil
Folks,
Let's hit this nonsense on the head. No more discussion of waveform analysis, it remains inconclusive, it is difficult to do, and ultimately it is corrupted by both low sampling rates and the horrific D/A converters in sound cards. Forget it, it's not effective and Nico was effectively saying this anyway with his haplesss attempt to give us all a listen.
Nico,
Thank you sincerely for the comprehensive input you have made, it has been considerable, above and beyond - not that you had any obligation to do anything. I sincerely hope you see fit to return to the thread, because your expertise is, to me and I'm sure to most others, indisputable. As a human being you are entitled to get your test clips the wrong way around - a simple enough mistake - and certainly not one to be pilloried about.
John,
Please leave this alone. The process has been flawed, chiefly because of the inaccuracies intrinsic in D to A conversion, and you have considerably upset Nico to the point where he is now leaving. You mention that as a man of science he should be amenable to criticism, fair comment, but you, as the critic, have an obligation to moderate the tone of your criticism so that it remains a discussion on objective, not emotive, terms. If you wish to prove yourself correct and Nico incorrect, please do it privately, not in a public forum. This issue has erupted as I have slept, and thus has gone unmoderated. No one here doubts you are smart, but you are brash, and need to pull your horns in. No one has all the answers, not even you, and attempts by any member of this forum to use the medium as a means of embarrassing others is both insidious and absurd.
No one is doing a service to this thread, regardless of technical input, if the entire discussion goes belly up and the principal technical player leaves because of unacceptable net etiquette. So please, give some thought to this and consider the consequences of the approach and tone you use. Correct people's errors by all means, but do it with grace and sensitivity. Realise that others have egos which must be managed, not confronted. I have been a member of DIYaudio since 2001, and I can number the truly disruptive individuals on the fingers of two hands. You are NOT one of those, but right now your behaviour has resulted in a huge eruption which is unwelcome, to say the least. And while I thank you for your technical input, I urge you to thwart your impulse to have the last word.
Folks,
This is a long, slow thead. Not much is happening fast. That is the nature of R&D and I make no excuses. The process is ongoing, piecemeal, and no one has built the final product at this point. Some excellent minds are working on the problem, and a solution will undoubtedly be found, but it will take time, and it is neither entertainment nor intellectual blood sport. Participate if you are sincere about helping and contributing in a mannerly way. Go elsewhere if your intentions are to show up others, or openly condemn. I have enjoyed private email and phone conversations with Nico Ras for some months, and know him to be an extraordinarily competent, loyal and worthy individual. Playing the man always ends in tears, and I'm furious about this.
I don't care what is said in objective terms about the technology, but any comment made about personalities is off limits and will be edited out in future. Please, cooperate, otherwise continuing evolution of the amp and survival of this thread will be threatened.
Hugh
Let's hit this nonsense on the head. No more discussion of waveform analysis, it remains inconclusive, it is difficult to do, and ultimately it is corrupted by both low sampling rates and the horrific D/A converters in sound cards. Forget it, it's not effective and Nico was effectively saying this anyway with his haplesss attempt to give us all a listen.
Nico,
Thank you sincerely for the comprehensive input you have made, it has been considerable, above and beyond - not that you had any obligation to do anything. I sincerely hope you see fit to return to the thread, because your expertise is, to me and I'm sure to most others, indisputable. As a human being you are entitled to get your test clips the wrong way around - a simple enough mistake - and certainly not one to be pilloried about.
John,
Please leave this alone. The process has been flawed, chiefly because of the inaccuracies intrinsic in D to A conversion, and you have considerably upset Nico to the point where he is now leaving. You mention that as a man of science he should be amenable to criticism, fair comment, but you, as the critic, have an obligation to moderate the tone of your criticism so that it remains a discussion on objective, not emotive, terms. If you wish to prove yourself correct and Nico incorrect, please do it privately, not in a public forum. This issue has erupted as I have slept, and thus has gone unmoderated. No one here doubts you are smart, but you are brash, and need to pull your horns in. No one has all the answers, not even you, and attempts by any member of this forum to use the medium as a means of embarrassing others is both insidious and absurd.
No one is doing a service to this thread, regardless of technical input, if the entire discussion goes belly up and the principal technical player leaves because of unacceptable net etiquette. So please, give some thought to this and consider the consequences of the approach and tone you use. Correct people's errors by all means, but do it with grace and sensitivity. Realise that others have egos which must be managed, not confronted. I have been a member of DIYaudio since 2001, and I can number the truly disruptive individuals on the fingers of two hands. You are NOT one of those, but right now your behaviour has resulted in a huge eruption which is unwelcome, to say the least. And while I thank you for your technical input, I urge you to thwart your impulse to have the last word.
Folks,
This is a long, slow thead. Not much is happening fast. That is the nature of R&D and I make no excuses. The process is ongoing, piecemeal, and no one has built the final product at this point. Some excellent minds are working on the problem, and a solution will undoubtedly be found, but it will take time, and it is neither entertainment nor intellectual blood sport. Participate if you are sincere about helping and contributing in a mannerly way. Go elsewhere if your intentions are to show up others, or openly condemn. I have enjoyed private email and phone conversations with Nico Ras for some months, and know him to be an extraordinarily competent, loyal and worthy individual. Playing the man always ends in tears, and I'm furious about this.
I don't care what is said in objective terms about the technology, but any comment made about personalities is off limits and will be edited out in future. Please, cooperate, otherwise continuing evolution of the amp and survival of this thread will be threatened.
Hugh
John,
Thank you for your measured response and acceptance of my criticism, much appreciated. I hope you continue to contribute, I really do, as you have great technical ability. I don't mean to single you or anyone else out, not my style, but neither do I resile from my comments. I am trying to keep this thread pleasant and informative, without confrontation. With smart people, that is always a challenge,
Cheers,
Hugh
Thank you for your measured response and acceptance of my criticism, much appreciated. I hope you continue to contribute, I really do, as you have great technical ability. I don't mean to single you or anyone else out, not my style, but neither do I resile from my comments. I am trying to keep this thread pleasant and informative, without confrontation. With smart people, that is always a challenge,
Cheers,
Hugh
Hugh,
Like I said, no problem. I have a pretty thick skin and the weight of criticism is always relative to the source - my ego is intact!
As for contribution, I'll probably follow my first instincts (from many days past) and stay away. My help thus far has been negligible - you probably won't miss it.
Goodluck! and goodbye.
Like I said, no problem. I have a pretty thick skin and the weight of criticism is always relative to the source - my ego is intact!
As for contribution, I'll probably follow my first instincts (from many days past) and stay away. My help thus far has been negligible - you probably won't miss it.
Goodluck! and goodbye.
Alright, I have my official opinion. Those who are interested can Email me; I won't post it here.
I think we need to leave the musical discernment up to Hugh. He's the one running the show and his amps have an outstanding track record AFAIK. I think subjective impressions should be kept private between those interested considering what's happened here.
- keantoken
I think we need to leave the musical discernment up to Hugh. He's the one running the show and his amps have an outstanding track record AFAIK. I think subjective impressions should be kept private between those interested considering what's happened here.
- keantoken
I'm absolutely delighted, I can assure you Nico. I'd call you the grand old man of DIYaudio if I wasn't just a tad older myself...... God, are we both that bl**dy old?
Today I meet up with another sparkling engineering mind, Paul Bysouth, we are going to discuss the finer details of crossfeed, tone and balance controls (and enjoy some fine coffee!).
Nico, I appreciate your altruism, your sharp mind, your loyalty, your extraordinary experience, and your measured, conservative approach to engineering. I appreciate John's scepticism, his insights, and his energy. I hope he returns too, I will admit.
I truly appreciate a thread where discussion is civilised, people are involved and interested, and manners are clearly observed. This medium is not good at creating friendships, our net personas are often very different to our face to face personality, but forum argument can easily cause deep hurt. I have a wonderful forum on audiocircle, rarely a harsh word spoken, and I police it like a benevolent dictator. I would like to see the same ethos pervading this thread.
I will always give unequivocal support to people who contribute, who are productive, and who show the forum community generous goodwill. And I like to give credit where it is due. Nico has done more for this thread than almost anyone, and I give him due appreciation for that gesture.
Welcome back, Nico!
Hugh
Today I meet up with another sparkling engineering mind, Paul Bysouth, we are going to discuss the finer details of crossfeed, tone and balance controls (and enjoy some fine coffee!).
Nico, I appreciate your altruism, your sharp mind, your loyalty, your extraordinary experience, and your measured, conservative approach to engineering. I appreciate John's scepticism, his insights, and his energy. I hope he returns too, I will admit.
I truly appreciate a thread where discussion is civilised, people are involved and interested, and manners are clearly observed. This medium is not good at creating friendships, our net personas are often very different to our face to face personality, but forum argument can easily cause deep hurt. I have a wonderful forum on audiocircle, rarely a harsh word spoken, and I police it like a benevolent dictator. I would like to see the same ethos pervading this thread.
I will always give unequivocal support to people who contribute, who are productive, and who show the forum community generous goodwill. And I like to give credit where it is due. Nico has done more for this thread than almost anyone, and I give him due appreciation for that gesture.
Welcome back, Nico!
Hugh
Hi Nico. No hard feelings I hope.
Hugh,
Not to be argumentative (though that is my nature): I made an observation based on my experience. If this is bad manners, I apologies to everyone, Nico especially.
And...
I have posted quite a bit here (more than twice as much as you Hugh, despite your being on this forum for much longer) and I have presented my work and my thoughts and opinions, in other words I've shared a lot of myself, put it out there. I have had to defend myself, laugh at myself, feel embarrassed at some of the things I've done or said even. I've also reaped the positive in that my work has been praised and I have learned SO much and "met" so many with the same mind set, my life is richer.
Maybe I'm different, maybe what drives me to share this stuff allows me to roll with the punches better, who knows? What is for me may not be for someone else and I should have been more sensitive.
Hugh,
Not to be argumentative (though that is my nature
): I made an observation based on my experience. If this is bad manners, I apologies to everyone, Nico especially. And...
I have posted quite a bit here (more than twice as much as you Hugh, despite your being on this forum for much longer) and I have presented my work and my thoughts and opinions, in other words I've shared a lot of myself, put it out there. I have had to defend myself, laugh at myself, feel embarrassed at some of the things I've done or said even. I've also reaped the positive in that my work has been praised and I have learned SO much and "met" so many with the same mind set, my life is richer.
Maybe I'm different, maybe what drives me to share this stuff allows me to roll with the punches better, who knows? What is for me may not be for someone else and I should have been more sensitive.
