Re: Re: The menace!!!!...reprise...
Besides jokes and personal comments, does anyone have anymore questions for me about blind tests or null difference tests? Can anyone objectively dispute these tests?
If amplifiers (or power conditioners, or whatever) really have the obvious sorts of differences people are talking about here shouldn't a person be able to hear them even when they don't know what they're listening to?
If Wondercaps really sound as awful as fdegrove suggests, shouldn't I be able to take two indentical high quality amps (Gainclones if you like), put Wondercaps in one, and say the $75 ones Peter Daniel prefers in the other, and have either person be able to pick them out in an A/B blind comparison running in their own system?
What if I put Wondercaps in, run a difference test and record both the RMS wideband amplitude and the spectrum analysis of the difference signal. Then I put the $75 caps in and repeat the difference test and compare the results. If the RMS value and spectrum are the same from both tests, are the caps changing the signal in ANY way? Can they possibly be audible then?
Thanks pinkmouse, that's good advice... so back to topic...pinkmouse said:Everyone- can we keep this thread on the intellectual high ground please, this is one of the most interesting topics in a long while, I'd hate to see it falling apart now.
Besides jokes and personal comments, does anyone have anymore questions for me about blind tests or null difference tests? Can anyone objectively dispute these tests?
If amplifiers (or power conditioners, or whatever) really have the obvious sorts of differences people are talking about here shouldn't a person be able to hear them even when they don't know what they're listening to?
If Wondercaps really sound as awful as fdegrove suggests, shouldn't I be able to take two indentical high quality amps (Gainclones if you like), put Wondercaps in one, and say the $75 ones Peter Daniel prefers in the other, and have either person be able to pick them out in an A/B blind comparison running in their own system?
What if I put Wondercaps in, run a difference test and record both the RMS wideband amplitude and the spectrum analysis of the difference signal. Then I put the $75 caps in and repeat the difference test and compare the results. If the RMS value and spectrum are the same from both tests, are the caps changing the signal in ANY way? Can they possibly be audible then?
DON'T CAVE IN PLS.
Hi,
Any founded reasoning as to why it would need deleting?
How can anyone be sure of the commercial intentions of those that attack others here?
For all we know some may have an axe to grind as well, so there you go.
At least you had the guts and honnesty to come forward with your intentions, for I think that's all they are for the moment.
More to the point, knowing you as a person here on the forum and you're morale I think you're the last person that should be accused of dubious practices.
Jorge,
If you can't distinguish between a threat and an expression of opinion... iI can only hope your amps "falla Portuguese".
So, let's shake hands on this and do some more work in the "Tubes" section.
Cheers,
Hi,
Any founded reasoning as to why it would need deleting?
How can anyone be sure of the commercial intentions of those that attack others here?
For all we know some may have an axe to grind as well, so there you go.
At least you had the guts and honnesty to come forward with your intentions, for I think that's all they are for the moment.
More to the point, knowing you as a person here on the forum and you're morale I think you're the last person that should be accused of dubious practices.
Jorge,
If you can't distinguish between a threat and an expression of opinion...
iI can only hope your amps "falla Portuguese".So, let's shake hands on this and do some more work in the "Tubes" section.
Cheers,
Hey everyone!
Don't give Peter D a hard time, after all I'm the one who asked him to show and tell. I take full responsibility!
But having said that I think it is FANTASTIC! What's more motivating than seeing someone design something and go boldly into the marketing frontier? Should be supported not criticized.
Besides old Hugh of AKSA uses this place shamelessly for free advertising all the time.
Don't give Peter D a hard time, after all I'm the one who asked him to show and tell. I take full responsibility!
But having said that I think it is FANTASTIC! What's more motivating than seeing someone design something and go boldly into the marketing frontier? Should be supported not criticized.
Besides old Hugh of AKSA uses this place shamelessly for free advertising all the time.
Re: Re: Re: Topological acuity....
....An impossible task precisely because no two pieces of music could remotely be described as identical...kapisch? Try comparing the waveforms of Vaughan's 'Lark ascending' with Barber's 'Adagio for strings' for a start.......
...and the notion that AES papers are written by 'academics with a particular agenda, and little or no experiance designing audio', is as ill-informed, as it is vacuous......The overwhelming bulk of audio technology as known today, is due to such pioneering members of the AES as T. Holman, (THX fame), Dolby, D. Self (currently at audiolab), G. Stanley, (at Crown), E. Benjamin, Sondermeyer, Dennis bohn of Rane,...etc...etc......People who posess more experiance more audio design experiance in each of their finger nails than you're ever likely to accumulate in your lifetime....dear...dear...
Fred Dieckmann said:
....An impossible task precisely because no two pieces of music could remotely be described as identical...kapisch? Try comparing the waveforms of Vaughan's 'Lark ascending' with Barber's 'Adagio for strings' for a start.......
...and the notion that AES papers are written by 'academics with a particular agenda, and little or no experiance designing audio', is as ill-informed, as it is vacuous......The overwhelming bulk of audio technology as known today, is due to such pioneering members of the AES as T. Holman, (THX fame), Dolby, D. Self (currently at audiolab), G. Stanley, (at Crown), E. Benjamin, Sondermeyer, Dennis bohn of Rane,...etc...etc......People who posess more experiance more audio design experiance in each of their finger nails than you're ever likely to accumulate in your lifetime....dear...dear...
United europe....
I think that two heads think better that one head...and the objetivists and the subjecivist can help each other part in the porsuit of good sound...
But some people claim to have all the reason...and that may to arrest the constructive dialog..
So back to audio discussion...
I think that two heads think better that one head...and the objetivists and the subjecivist can help each other part in the porsuit of good sound...
But some people claim to have all the reason...and that may to arrest the constructive dialog..
So back to audio discussion...
Well, there's certainly problems, objectively, with using a null test as an indicator of amp "quality" for reasons I've already stated and that haven't been answered:
1. "Quality" is a matter of how well an amp achieves its design goals. Not all amps are intended to have an output that replicates the input times a scalar. If you want an amp with large amounts of 2nd HD and a high source impedance, it won't pass a null test, no matter how much the designer and his customers like the sound.
2. It is possible, actually probable, that two amps which perform differently in a null test will sound indistinguishable in a controlled test.
3. Objectively sonically-neutral phenomena can result in very poor (misleadingly so) performance on a null test. This might be considered a subset of point 2.
1. "Quality" is a matter of how well an amp achieves its design goals. Not all amps are intended to have an output that replicates the input times a scalar. If you want an amp with large amounts of 2nd HD and a high source impedance, it won't pass a null test, no matter how much the designer and his customers like the sound.
2. It is possible, actually probable, that two amps which perform differently in a null test will sound indistinguishable in a controlled test.
3. Objectively sonically-neutral phenomena can result in very poor (misleadingly so) performance on a null test. This might be considered a subset of point 2.
Re: Re: Re: The menace!!!!...reprise...
So how about it, if the both amps have the same "error signature" (difference signal) with both kinds of caps, can they still make an audible difference?
Oh, and that difference test would be with the sort of music you like to use for critical listening tests running into real speakers--not sine waves and test loads.nw_avphile said:
So how about it, if the both amps have the same "error signature" (difference signal) with both kinds of caps, can they still make an audible difference?
misinformation....by Fred
Re: Re: Re: Topological acuity.... Post #245
quote:
Originally posted by Fred Dieckmann
It surely an impossible task, why waste time on it. And no evidence ever will be presented I guess because the test are perfect. What the heck do you do for a living? You sound sort like an engineer, but I can't imagine that. The first time anybody asked you to do anything challenging I would think you would say it can't be done because somebody else said it couldn't be done, or it had never done it. My last boss would have eaten you alive. In the telecom industry, I have worked on plenty of task, troubleshooting, measurements, and designs that:
A. Had never been done before.
B. Couldn't ever be done.
C. Would cost to much.
D. Couldn't be measured because someone else could not measure it.
E. Could never be done within a certain time.
In fact most of the engineering I have done in conflict one or more of the previous objections. This constant fall back on the established engineering orthodoxy and status quo is ridiculous. Most of the papers in the AES Journal are written by academics with a particular agenda and little or no experience designing audio. If Dougless Self is a brilliant designer why doesn't he have a string of successful commercial products out there. I have never seen any. I guess its all be cause of the great audiophile conspiracy.
This dredging up the XL-280 and Hafler test is interesting too. I looked at the schematic and it very much looks to be an Erno
Borbely design based on the parts choice and topology. There are lots of 1% metal film resistors, polypropylene caps, polycarbonate caps, and even two carbon comp resistors. The Toshiba Jfets in the front end are are favorite of many of the lunatic fringe set. In fact many of these part types are what the "tweaker delusional audiophile" set recommend. Erno Borbely is a very talented audio designer with a string of successful commercial designs. He is an advocate of measurements and has written articles on distortion measurement. He also talks about the sound of different passive components. How could that be?
Mikek says:
....An impossible task precisely because no two pieces of music could remotely be described as identical...kapisch? Try comparing the waveforms of Vaughan's 'Lark ascending' with Barber's 'Adagio for strings' for a start.......
...and the notion that AES papers are written by 'academics with a particular agenda, and little or no experiance designing audio', is as ill-informed, as it is vacuous......The overwhelming bulk of audio technology as known today, is due to such pioneering members of the AES as T. Holman, (THX fame), Dolby, D. Self (currently at audiolab), G. Stanley, (at Crown), E. Benjamin, Sondermeyer, Dennis bohn of Rane,...etc...etc......People who posess more experiance more audio design experiance in each of their finger nails than you're ever likely to accumulate in your lifetime....dear...dear...
Re: Re: Re: Topological acuity.... Post #245
quote:
Originally posted by Fred Dieckmann
It surely an impossible task, why waste time on it. And no evidence ever will be presented I guess because the test are perfect. What the heck do you do for a living? You sound sort like an engineer, but I can't imagine that. The first time anybody asked you to do anything challenging I would think you would say it can't be done because somebody else said it couldn't be done, or it had never done it. My last boss would have eaten you alive. In the telecom industry, I have worked on plenty of task, troubleshooting, measurements, and designs that:
A. Had never been done before.
B. Couldn't ever be done.
C. Would cost to much.
D. Couldn't be measured because someone else could not measure it.
E. Could never be done within a certain time.
In fact most of the engineering I have done in conflict one or more of the previous objections. This constant fall back on the established engineering orthodoxy and status quo is ridiculous. Most of the papers in the AES Journal are written by academics with a particular agenda and little or no experience designing audio. If Dougless Self is a brilliant designer why doesn't he have a string of successful commercial products out there. I have never seen any. I guess its all be cause of the great audiophile conspiracy.
This dredging up the XL-280 and Hafler test is interesting too. I looked at the schematic and it very much looks to be an Erno
Borbely design based on the parts choice and topology. There are lots of 1% metal film resistors, polypropylene caps, polycarbonate caps, and even two carbon comp resistors. The Toshiba Jfets in the front end are are favorite of many of the lunatic fringe set. In fact many of these part types are what the "tweaker delusional audiophile" set recommend. Erno Borbely is a very talented audio designer with a string of successful commercial designs. He is an advocate of measurements and has written articles on distortion measurement. He also talks about the sound of different passive components. How could that be?
Mikek says:
....An impossible task precisely because no two pieces of music could remotely be described as identical...kapisch? Try comparing the waveforms of Vaughan's 'Lark ascending' with Barber's 'Adagio for strings' for a start.......
...and the notion that AES papers are written by 'academics with a particular agenda, and little or no experiance designing audio', is as ill-informed, as it is vacuous......The overwhelming bulk of audio technology as known today, is due to such pioneering members of the AES as T. Holman, (THX fame), Dolby, D. Self (currently at audiolab), G. Stanley, (at Crown), E. Benjamin, Sondermeyer, Dennis bohn of Rane,...etc...etc......People who posess more experiance more audio design experiance in each of their finger nails than you're ever likely to accumulate in your lifetime....dear...dear...
Peter Rules!
If it were not for Peter's posts, which I attribute to raising the standards of the quality of our projects, most us would be happy with the amplifiers we built in cake pans.
We all owe him a lot for sharing his time and experience and more power to him if he wants to sell some of his work.
Regards,
Jam
P.S. ... besides he is one the few decent moderators left.
If it were not for Peter's posts, which I attribute to raising the standards of the quality of our projects, most us would be happy with the amplifiers we built in cake pans.
We all owe him a lot for sharing his time and experience and more power to him if he wants to sell some of his work.
Regards,
Jam
P.S. ... besides he is one the few decent moderators left.
To Peter...
This post is not sarcastic...i'm talking sincearly...
I wish you the best in the world of business...if sometimes i made some remarks is because i think that your target is the Hi-Fi consumer...so the brands of capacitors the sound of wires are much important in a magazine hi-fi revue...but you can't espect that in a world wide forum like this there are no others people with diferents opinions...
So let's respect anyone opinion...and make this forum a democracy!!!
For me no reason to delet your post!
This post is not sarcastic...i'm talking sincearly...
I wish you the best in the world of business...if sometimes i made some remarks is because i think that your target is the Hi-Fi consumer...so the brands of capacitors the sound of wires are much important in a magazine hi-fi revue...but you can't espect that in a world wide forum like this there are no others people with diferents opinions...
So let's respect anyone opinion...and make this forum a democracy!!!
For me no reason to delet your post!
Thanks SY... my thoughts below...
Where this gets a bit tricky is when you ask "Ok, so how good of a null is good enough?" In other words, what level and type of difference signal can be strongly argued as inaudible. In my experience it's around -50db within the audio band.
If you bandwidth limit the equipment you're using to monitor the difference signal to 20k (something that's very easy to do with my setup) I find if the difference signal is at last 50db down from the output of the amplifier nobody can pick it out from ANY other amplifier with at least as low of difference signal. And that's regardless of the frequency spectrum of the difference signal. To be safe, however, I usually say -60db in case there are some really golden eared types and systems out there that can pick stuff out that mere mortals can't. The best amp I've tested managed -70db.
But you're right, a more accurate way to handle this would be to somehow "weight" the difference signal components according to how audible they're likely to be (and/or compensate the test so that it won't detect inaudible differences in the first place). That's opening a much bigger can of worms however, and I would argue unnecessary.
Yes I agree. If we're back to wanting amplifiers that intentionally alter the sound (amplifiers as "art") the null test could still be useful but you wouldn't want to minimize the difference signal if you're designing for errors.SY said:
Agreed, but what about the converse? If they measure similarly on the test, won't they sound the same? So in my capacitor example above, wouldn't the null test save you the trouble of doing the blind test if both caps produced extremely similar difference signals?SY said:
I also agree, but that still doesn't invalidate the test as an indicator of all amplifier distortions. In other words, if you work to minimize ALL forms of distortions while playing real music and driving real speakers, you're certainly not hurting anything are you?SY said:
Where this gets a bit tricky is when you ask "Ok, so how good of a null is good enough?" In other words, what level and type of difference signal can be strongly argued as inaudible. In my experience it's around -50db within the audio band.
If you bandwidth limit the equipment you're using to monitor the difference signal to 20k (something that's very easy to do with my setup) I find if the difference signal is at last 50db down from the output of the amplifier nobody can pick it out from ANY other amplifier with at least as low of difference signal. And that's regardless of the frequency spectrum of the difference signal. To be safe, however, I usually say -60db in case there are some really golden eared types and systems out there that can pick stuff out that mere mortals can't. The best amp I've tested managed -70db.
But you're right, a more accurate way to handle this would be to somehow "weight" the difference signal components according to how audible they're likely to be (and/or compensate the test so that it won't detect inaudible differences in the first place). That's opening a much bigger can of worms however, and I would argue unnecessary.
nw, there are deviations that aren't worth bothering with. Consider two amps with identical and vanishingly low distortion. They null nearly perfectly. Now, put a perfect 1 ms delay at the input of one of the amps. Now the nulling at midband and high frequencies is horrible, yet you have a "distortion" that is meaningless. HD and IM aren't the only things out there.
And another question in the case of HD and IM is what to do (if anything) to minimize them even after they're below the threshold of audibility. If I have a transparent amp (transparent in that input and output cannot be distinguished by a skilled listener) with 0.5% THD and a 0.1 ohm source Z and want to make that null better, am I "hurting anything" if I increase the parts count, making the amp more expensive and less reliable? Am I "hurting anything" if I increase the O/P stage idle current, thus increasing heat, lowering reliability, and increasing the customers' electricity bills?
In the limited case where lowering distortion or source Z past an already-insignificant amount carries no cost or reliability penalty, sure, why not? But that's only one case, and I'd argue that it's exceptional.
The delay...
The beuty of this test is if you put a perfect 1ms delay and hear the null...the null is a perfect rendiction of the musical signal...
But in the case of distortion or frequency dependent delay what you will hear at the null point is a very distorted rendiction of the musical signal...
The null tell everything!!
The beuty of this test is if you put a perfect 1ms delay and hear the null...the null is a perfect rendiction of the musical signal...
But in the case of distortion or frequency dependent delay what you will hear at the null point is a very distorted rendiction of the musical signal...
The null tell everything!!
I'm not trying to be cranky, but can we please try for a little better signal-to-noise ratio in this thread? On the previous page, out of 15 posts, 5 have something to do with the thread topic. Some previous pages are even worse.Steve Eddy said:
You kidding? Soon as my feet hit the floor in the morning I'm "at work."
se
- Status
- Not open for further replies.