Another thing, I see a few people here talking about the use of measuring instruments in very derogatory terms.
The fact is that instruments are more reliable and sensitive than human senses. Do you really imagine that you can see smaller with your naked eye than you can with a microscope? Or that you can discern detail better at a distance without a telescope?
The same is true of audio and electrical instruments.
If you fly in cloud, you learn to trust the instruments or you end up dead, although you probably won't get a licence anyway. And if you're not flying, then you better hope the pilot's on instruments.
I saw earlier someone suggesting the use of drugs. In the case of those who believe that they CAN hear the difference (between cables) this may be the best or perhaps the only solution.
One of the things that taking LSD teaches you in no uncertain terms is: - YOU CAN'T ALWAYS DEPEND ON THE EVIDENCE OF YOUR SENSES.
w
djk
$100.
Put up or shut up!
The fact is that instruments are more reliable and sensitive than human senses. Do you really imagine that you can see smaller with your naked eye than you can with a microscope? Or that you can discern detail better at a distance without a telescope?
The same is true of audio and electrical instruments.
If you fly in cloud, you learn to trust the instruments or you end up dead, although you probably won't get a licence anyway. And if you're not flying, then you better hope the pilot's on instruments.
I saw earlier someone suggesting the use of drugs. In the case of those who believe that they CAN hear the difference (between cables) this may be the best or perhaps the only solution.
One of the things that taking LSD teaches you in no uncertain terms is: - YOU CAN'T ALWAYS DEPEND ON THE EVIDENCE OF YOUR SENSES.
w
djk
$100.
Put up or shut up!
I measured the 'ring resonators' with a B&K 1" measurement mike, independently calibrated and shown to be accurate by the B&K mike measurement team to beyond 18KHz. I did a discrete frequency sweep, making sure that the output of the amp was always the same voltage within .1dB. I also did an independent measurement with an Altec Lansing 1/3 octave real time analyzer. Is that good enough? Most probably still have the measurements, somewhere.
An easier, more entertaining (IMO), and legal way to accomplish the same thing is to spend 10 minutes with a skilled sleight-of-hand artist. Close-up magic is fabulously entertaining, and good practitioners can fool me even when I'm well aware of their methods. Sure, I know how cups and balls is done, same with three card monty, but a good manipulator just blows me away.
"If you fly in cloud, you learn to trust the instruments or you end up dead, although you probably won't get a licence anyway. And if you're not flying, then you better hope the pilot's on instruments."
I build and service ILS devices, both civilian (ARN 108) and military models (ARN 147 with the 1553 buss).
Next time you send yours in for service or re-certification, let me know, and I'll charge you a bit extra.
(LOL)
I build and service ILS devices, both civilian (ARN 108) and military models (ARN 147 with the 1553 buss).
Next time you send yours in for service or re-certification, let me know, and I'll charge you a bit extra.
(LOL)
eStatic said:
The problem with Behringer tends to do more with their manufacturing accidentally sourcing counterfeit parts on a semi-regular basis.
Whee, offshore manufacture... can be perfect, can be terrible, you never know as a consumer... Actually, their preamp stages are on the noisy side but not awful.I'm in the same category as eStatic honestly. I don't deny there are are situations-- measurable and quantifiable-- where a particular amp and a particular set of speakers get along swimmingly or not well at all [are we too high-end here to be talking about passive crossovers? I'll assume so]. Of course it's possible to have an amp accidentally operate outside of its capabilities, designed or implemented. These newfangled transistor amps have just gotten us very used to most amps working well with most speakers.
But given these newfangled transistor thingies, near-zero output impedence, proponderance of power and modern design tools, there are precious few amps of any quality that ever have to strain to deliver their full design spec to any louspeaker a user cares to strap on.
[I will note a comment Planet10 made recently about the FR125S and single ended amps-- he said SE makes them 'fart'. I assume that's a pretty obvious sound, could you potentially sample an example of that? I'd love to analyze it. I could slap together an SE amp here but I don't actually have one handy. I would think it's likely due to a design flaw/limitation in a specific amp or amp topology. More details?]
If I can look at the signal going into amp A, the signal coming out, compare it to amp B and the measurements say 'there's no audible difference', I believe the measurements. We engineers are very good at quantification and measurement when a bee gets into our collective bonnet.
If you can hear a difference, I can measure it electrically. In fact, I'll be able to measure a ton of differences you'll not be able to hear. But if the response measures flat, the phase measures flat, the THD is low and there are no output oscillations, undue noise or RF down-modulations [all design or setup flaws], they're going to sound the same. Time invariant nonlinearities all show up in the THD. Time variant nonlinearities and noise just mean you need to do more than a single sweep ;-P You can watch the realtime response/phase of an amp on any music input for as long as you'd like.
The example of different resistors: well, yes, they'll behave slightly differently in terms of self noise, temperature drift, self-inductance, etc... could these make a difference in an amp? Conceivable, if the design is otherwise sensitive to one of these parameters, eg, self inductance on a NFB leg prone to oscillation. I'd call that a design flaw, but we'll leave it go. Can you hear the difference? Only if it causes the design to malfunction, and I'll be able to measure that electrically long before you can hear it. So should have the engineer who designed the circuit. [I use metal film myself because they're smaller for the power handling capacity and have better temp stability.]
....*awesome*.
Not only is this appeal to authority, but authority by association! Come on now...john curl said:
Plus, even if someone has a significant contribution to a field doesn't mean his word should be taken without due examination. Look at Tesla for example--he advanced the field yet obviously had a lot of crackpot ideas as well.
abzug said:
I can't find any reference for the following quote, but I remember reading it as a child in a Tesla biograpy, in the chapter describing how Edison designed to make sure the first electric chair would be fed by alternating current (Tesla's invention) rather than Edison's own 'safer' DC utility service:
"They laughed at Galileo. They laughed at Einstein. Nobody laughed at Tesla." [the implication being that he mostly made people nervous...]
Monty
"Mad scientists are too dangerous-- even criminals don't like them." --MoS pg 296
No, I am just rubbing it in. You actually THINK that you know what R. Feynmann would do and think from a few quotes. Jack says you are wrong. I know him, and I don't know you very well. I am trying to get certain people to realize that they really don't know, even when they quote.
Talk about 'Appeal to authority'
Talk about 'Appeal to authority'
The photography comparison is too weak. Sound in real time is ridiculously more complex than a printed sheet of paper. Greiner admits it in elaborating the difficulty of performing time-multiplexed audio comparisons when it suits the argument of trivializing audiophiles, then dispels those hurdles with a wave of the ABX wand when it suits the argument of trivializing audiophiles. If audio is so much more complex, why not ABX testing in photography? It should work leagues better since the subject is 100% static. To my ear it's a question he labours to sidestep. ABX should, in the standard logic, minimize the possibility of a stronger personality asserting an opinion on blacks, colour accuracy, what have you, on others. Greiner's description of the photographer's process reads more like battle for authority than methodologically valid. ABX would have ended the Fuji/Kodachrome debates decades ago! The more deeply it's considered, the less sense it makes to me for him to have brought up the comparison at all. (I don't disagree with blind testing in principle, I just haven't read any accounts yet in which the methodology wasn't cynical comedy.)
Regarding the home-brew nature of audio, has Greiner never seen an amatuer telescope building competition? Builders grinding lenses and mirrors, fabbing gyros and focus mechanisms of extraordinary crafstmanship and precision.... astrologists?
Sig with apologies to JC.
Regarding the home-brew nature of audio, has Greiner never seen an amatuer telescope building competition? Builders grinding lenses and mirrors, fabbing gyros and focus mechanisms of extraordinary crafstmanship and precision.... astrologists?
Sig with apologies to JC.
rdf said:
Audio is not more complex. Greiner never 'admitted' any such thing. He said the process of comparison (not the audio) is more complex.
And as someone who has poured time and attention into grinding optics (Man, I'm never doing *that* again) I didn't come out of the process believing my results were somehow superior in a mystical, unmeasurable way. Optical precision is trivially measurable. That's why you don't have quacks selling $7k telescope cables that "improve the warmth and feel of the optic image in ways cold, useless, incapable Science fails to measure". And that was Greiner's point.
Hm, I think it's time to go get Penn & Teller.
I have a pre-made 4" telescope that was made by Tasco. I have owned at least 5 Tasco telescopes over the decades. Every one is or was lousy, except the very first one that I got in about 1954. Why? Didn't every one of them meet a minimum spec of visual quality? I know people who have hand made units up to 22" They seem to work, OK. Other people have the same size telescopes as me by Celestron and other quality brands, and they work great. What could be wrong with my telescope? It is supposed resolve to its physical limit, but it doesn't seem to. Why?
This is a parallel example to audio design and execution.
This is a parallel example to audio design and execution.
john curl said:
I suspect anyone with the proper equipment could tell you in a second. You don't understand why your telescope is inferior, so *the entirety of the scientific method is invalid*? C'mon John! This argument wouldn't fly in a high school debate.
Just keep running in circles with your hands up asking 'Why?' That'll convince us all. You bought a telescope that suffers from quality problems. Lord knows, we all buy poorly made things on a regular basis. But that somehow means I should trust that you build good amplifiers without the aid of quantitative measurement and testing, more, that this somehow means you know the Fallacies of Science. *Makes perfect sense*.o.
I'm out. I want to finish updating my spectrum analyzer app tonight and tomorrow so the folks who actually believe that the transistor was invented by science, not given to humanity by magic fairies, have one more tool for building better DIY amps instead of just pleading 'whyyyyy?' or worse... buying solid silver interconnects and hoping *that* fixes the hum problems.
Last post in this thread, I'm unsubbing. I'll PM the folks who wanted to know about the spectrum analysis app. Bye, it's been fun. It just kinda stopped being fun is all.
xiphmont said:
A sample would be low in the over long queue. In one particular day we had the same thing happen with a very good SEP EL84. an SE 845 and a Mini Aleph.
I hope you are using a loudspeaker (actually a good variety) of loudspeakers as load, and something more complex than a sin as signal.
dave
xiphmont said:
xiphmont, I don't think anybody will disagree with you on this, provided (as planet 10 also said) you do your measurements with real speakers connected and thorough measurements are done. I think the real challenge will be to find two amplifiers that will measure the same.
I don't think it is possible to build a good amplifier without instruments (i.m sure John Curl will agree with this also) but I believe it is important to do listening comparisons between designs also. I believe good sounding amplifiers will measure good, but I'm not sure that you can say an amplifier that measure good will sound good.
Something else, I believe to get optimal results, an amplifier must be designed to match a certain speaker, no one amplifier will work optimally with any type of speaker connected, nor is it worthwhile to build a super amplifier to drive a low quality speaker.
André
Do all amplifiers sound the same?
I don't know, I never listened to what comes out of an amplifier. I only ever listened to complete systems.
This may sound trivial, so let me explain:
There is an assumtion that has not been made explicit, namely, that the components of an audio system can be analyzed in isolation and that the results can be added to reach a conclusion on the sound of the system as a whole.
I've made some observations (measurements) that challenge this assumption:
System Distortion part 4
These measurements are part of my effort to explain the difference in sound (as perceived by me on my system in my room) between the different amps I have.
My single ended tube amp is as simple as can be, just an input transformer, a 300B and an output transformer. The power supply is another matter entirely, it is heavily filtered an fully regulated.
Because I wanted to look in detail at the harmonics I decided to use the minimum hold function of the analyzer and average a large number of measurements (200). I measured the distortion on the amp output loaded with 8.2ohm, the amp out with the loudspeaker as a load and the in-room distortion.
In short: my SET amp has the lowest distortion in the room. The stepped sinusoidal plots show that the Nad performs better, but if higher harmonics are included the SET performs better on THD.
And then there is the noisefloor. Take a look at what happens to the noisefloor of the Nad when signal is applied and compare it to the result for the SET amp.
A remark on the power supply harmonics:
Power supply ripple is 100Hz and even harmonics, this is the part that can be modelled with PSU designer. The 50Hz and odd harmonics are the result of common-mode noise originating from the mains and rectifiers.
I don't know, I never listened to what comes out of an amplifier. I only ever listened to complete systems.
This may sound trivial, so let me explain:
There is an assumtion that has not been made explicit, namely, that the components of an audio system can be analyzed in isolation and that the results can be added to reach a conclusion on the sound of the system as a whole.
I've made some observations (measurements) that challenge this assumption:
System Distortion part 4
These measurements are part of my effort to explain the difference in sound (as perceived by me on my system in my room) between the different amps I have.
My single ended tube amp is as simple as can be, just an input transformer, a 300B and an output transformer. The power supply is another matter entirely, it is heavily filtered an fully regulated.
Because I wanted to look in detail at the harmonics I decided to use the minimum hold function of the analyzer and average a large number of measurements (200). I measured the distortion on the amp output loaded with 8.2ohm, the amp out with the loudspeaker as a load and the in-room distortion.
In short: my SET amp has the lowest distortion in the room. The stepped sinusoidal plots show that the Nad performs better, but if higher harmonics are included the SET performs better on THD.
And then there is the noisefloor. Take a look at what happens to the noisefloor of the Nad when signal is applied and compare it to the result for the SET amp.
A remark on the power supply harmonics:
Power supply ripple is 100Hz and even harmonics, this is the part that can be modelled with PSU designer. The 50Hz and odd harmonics are the result of common-mode noise originating from the mains and rectifiers.
xiphmont said:
M: I came here for a good argument.
A: No you didn't; no, you came here for an argument.
M: An argument isn't just contradiction.
A: It can be.
M: No it can't. An argument is a connected series of statements intended to establish a proposition.
A: No it isn't.
M: Yes it is! It's not just contradiction.
A: Look, if I argue with you, I must take up a contrary position.
M: Yes, but that's not just saying 'No it isn't.'
A: Yes it is!
M: No it isn't!
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