Yet another bold claim...

Steve,
An interesting point regarding feedback control.
My grounded grid pre has 1 resistor in the feedback loop, around 300K from memory. Many people on the transcendant forum seem to have played with values, some changed and others went back to the original value.
It wouldnt be to much hasle to use a variable resistor in that place and play around.
I might look into this.

 

True, but the difference is that pretty much every single aspect about the way a car behaves is measurable and scientifically understood and if you want to you can change that behaviour, the way it handles, the level of steering feedback, understeer/oversteer by applying science and engineering principles (and a lot of money usually!). There's no black magic and pseudo-science in the design of cars. It's cold hard engineering facts.

Another key difference is that there is no singular aim for car manufacturers. There's no such thing as the "perfect" car. The design and purpose behind a Nissan Micra is quite different to that of a Ferrari 430. There is no single criterion by which you can judge whether any car, as a whole, is better than another. It all depends what you want the car to do. If you want an economical car, you look at it's MPG measurements. If you want a lot of luggage space you look at the boot volume measurements. If you want a fast car you look at power, power to weight ratio, acceleration etc. figures. You weigh up the criteria that are important to you and trade them off against others until you find something that fits your needs and your budget as best as possible. Beyond that there are of course many totally subjective factors in buying a car. How it looks, it's brand image and many others.

With hifi it's different. We all want the same thing. Everyone is striving to get the most realistic, most "you are there", perfect, 100% fidelity sound. There is a theoretically perfect hifi system, and how close any given system is to that goal is measurable.

Michael.

 

"We all want the same thing."

Unfortunately michael this is where your argment falls down. People may well use the same terminology about what they are trying to achieve but the reality is often very different between individuals as to exactly what they think contitues "accurate" "natural" etc etc bass, treble, mids, dynamics or whatever.

So whilst it's true that "in theory" a perfect amplifier (or hi-fi system) is an objective and fixed goal. In practice it can never exist.

For instance. What does "dry" bass mean to you? Describe it in words as accurately as you can. I may well agree with what you've written, but the likelyhood that if we were both able to adjust the same systems bass response until it constituted what we would consider "dry" bass, that the results would be the same is small.


GTM

 

But it's not important what they (or I) think constitutes accurate, it's important what is accurate.

If a recording of a cello sounds like a real cello then it's accurate. Even if I perceive a cello to sound different to the way you do, if the sound waves reaching my ears from a system are the same as those from a live cello I will think it sounds like a cello, and so will you.

Now, if we took a recording of a cello and perhaps warmed it up by tweaking up the bass response a little and then played the original and the tweaked version to a group of people, it's quite possible that many would prefer the tweaked version or think it sounded more realistic (or both) but they would be wrong. Once presented with a real cello playing infront of them they would then realise this.

The trouble is (and it's one of the reasons that subjectivity in audio is such a problem) that human audio memory is extremely poor. Our ability to remember precisely how something sounds is almost non-existent so we are totally unable to make any accurate judgement about how realistic a system sounds just by listening to it, even if it's playing a recording of a live performance that we may have heard only hours ago.

Michael.

 

Let's start from begining:

1) Accuracy means output equal to the input;

2) Tube Dude's null test does tell objectively if an amp is accurate or not;

3) Accuracy is a good thing because I want to hear the way musicians want their music to be heard when they closely work with sound engineers to accomplish that, be it in a studio or in a live performance;

4) An accurate amp will always sound better than one that isn't, because of point 3;

5) Why accuracy may not sound always good or nice? I'll give you an example: the trumpet is a beatiful instrument with a large dynamic range and sometimes it can sound (I mean live sound) really agressive if that is the trumpetist will (or lack of skill);

6) Tube Dude's amp is virtually a perfect amp because its null test when driving real speakers with "real" music is almost perfect;

7) Tube Dude's amp does use lots of global negative feedback;

8) I heard Tube Dude's amp in my system with both Craffts and the Yammies, therefore I have an absolute reference as far as amplification is concerned;

9) I heard the Rotel 1062 in my system before I null tested it, the null test just confirmed my first impressions;

10) The 1062 performs closely to what I remember from Tube Dude's amp in my system (and that is not easy to forget);

11) I heard the Sim I-5 and the Nu-Vista M3 in my system with the Craffts and the DAC64, I prefered the Nu-Vista;

12) I sold the Nu-Vista because I couldn't live with it anymore, which proves, if the Sim I-5 is in fact a better amp like Wm and Merlin say so (and I agree), that the "ears" not always can make the right judgement;

13) Now I would like to null test the Sim I-5 just to prove myself that I'm right about what I remember of its sound, which never made me feel what the 1062 does;

14) No overall negative feedback is not the right path to accuracy;

15) I am not here to inflame and I do believe in Dynaudio's technical specifications: from 20kHz down to 40Hz you have 120dB max SPL with THD+IMD < 1%.

 

So BD, WTF are you hanging round here?, why not take TD to the patent office pronto, then a trip to the already lining up electronics manufacturers ready and eger to incorperate the design in the next awesome piece of kit.
I have to be honest here, you are more up your own bum than the whole of the angle iron forum combined and that takes some doing, I doff my hat off in respect of your single mindedness, though I feel an intensive corase of physco thereopy would be extremely benefical

 

Bloody hell...

4) An accurate amp will not ALWAYS sound better. What you mean to say is you always prefer the sound of an accurate amp due to reason pointed out in '3)'.

12) I guess you made a typo here because you just said you agree the Sim I-5 is a better amp. If the purpose of your amp is purely for listening enjoyment , your ears always make the correct judgement. Lets face it, there is no Hi-Fi which sounds 100% real so there is nothing wrong with sweetening the sound up a bit.

15) It means when playing white noise at full volume there is a max SPL reading of 120db. This does not mean they produce 40hz at 120db, it means at one point in the test, one frequency reached 120db. i.e. Do they have a flat response when playing at 120db? I doubt it.

You have already contradicted yourself so I can't be bothered to argue anymore. Believe what you want too BD, you will be the one with a, shall we say, less than perfect sounding Hi-Fi! Can I go in the submarine next time? lol

 

i think 'up his own bum' covered it rather well.

 

I can't speak as an amplifier designer but from a loudspeaker perspective there's some very muddy thinking going on here.

Wrong on both points here, michaelab.

Accurate simply means that the 'output' is the same as the 'input'. That's necessary but not sufficient for truth and, sorry mate but truth outranks accuracy for those of us who are seeking the 'being there' experience.

If the sound waves reaching your ears are the same as those from a live cello, you will not necessarily think it's a cello, and neither will I, unless the sound waves are also arriving with the same dispersion and ambient characteristics. Neither moving coil, electrostatic or NXT panel speakers are capable of giving the same dispersion and ambient characteristics as live musical instruments, even if the frequency response, distortion, dynamic range and transient behaviour were faultless.

Now, in view of the different balances of these parameters (frequency response, distortion, dynamic range, transients, dispersion, ambience, etc.) in different equipment, it becomes clear that 'truth' is subjective.

BD, Can I respectfully suggest that YOU start at the beginning (well probably not but I will anyway)?

Firstly, please read my response to michaelab above. Read it again until you understand the difference between truth and accuracy (at least, the truth according to 7V).

Next, stop reading, take your head out of your text books and listen to some music - live and recorded.

Oh, and no need to thank me. Your increased happiness and my not having to wade through this drivel will be thanks enough.

 

Steve, I take your points, but IMO you can't begin to get close to "truth" unless you have accuracy. Unless the signal reaching the speaker is 100% accurate then it doesn't have a hope in hell of reproducing "the truth", no matter how good it's dispersion and ambient characteristics are. Also, "the truth" is absolutely NOT subjective. It is (in the case of a live recording) an exact facimile of the original live sound in every aspect (frequency response, distortion, dynamic range, transients, dispersion, ambience, etc.), there is only one "truth", so it cannot be subjective.

Michael.

 

Basically, I agree with your comments, Michael.

What I'm saying is that the 'one truth' is unattainable. To choose between two (or more) 'near truths' IS subjective.

 

OK, I can agree with that.

Michael.

 

No, wait a minute. That can't be right. I'd better rethink my whole philosophy, here.

PS: Could it be the new, improved logo working its magic?

 

Like I said before I am happy... I was trying to share what made me happy.

But it seems to me that what made me happy makes you unhappy... so, I'm sorry!

I've abondoned theory and started to measure and listening, and then correlating both. What I got so far is very simple:

A more accurate amp, with a better null, effectively sounds always better. Period. Thank you Tube Dude for give me this powerful tool to the truth.

And for those of you who don't believe in accuracy I want to ask how can the stereo effect be realized without accuracy?

Just a clue... at high frequencies the sound become directional enough for the head to shade the distant ear causing what is called an inter-aural intensity difference. A transient has an unique aperiodic waveform which suffers no ambiguity in the assessment of inter-aural delay between two versions. One degree change in sound location causes an inter-aural delay of 10 microseconds. The smallest detectable inter-aural delay is 6 microseconds. Now the big claim...

THAT SHOULD BE THE CRITERION FOR SPATIAL REPRODUCTION ACCURACY !!!


PS: The Sim I-5 is a better amp than the MF Nu-Vista M3 and I liked the MF A1000 better than both. I null tested the Rotel 1062 and the A1000 and the 1062 is the only one about which I can objectively say accurate.

 

So BD, you've got a new text book.

Well, you're right. Accurate hi-fi will produce a very precise stereo image. Of course, if your speakers have crossover frequencies above about 200Hz, you are unlikely to have very precise imagery all of the time because of phase and dispersion problems at and around the crossover point. However, leaving that aside for now, 'accurate' hi-fi will produce a very precise stereo image.

So is that the truth? Well sort of ...

... if you're listening to a brass band in an open field.

- not however, if you're in a theatre or concert hall. Because in a concert hall the stereo image will not be the same as your 'accurate' hi-fi. There are all sorts of reflections and reverberations that are not reproduced accurately by conventional speakers ...

... Not even mine.

So, precise stereo image? Yes.
'Accurate'? Perhaps.
The truth?

... Put your new book away and get out more.

"unique aperiodic waveform which suffers no ambiguity in the assessment of inter-aural delay" indeed!

 

As long as both chanels perform exactly the same (given the same signal) you will percive a stereo image.

As all Hi-Fi I know of does this, it would explain why stereo imaging is much more a factor of listening room acoustics, frequency response and detail retrieval etc.. - all of which can be tailored to sound better to certain people. This would also explain why in my experience many studio monitors which are technically very accurate, do not image as well as less technically accurate Hi-Fi speakers.

Thats very nice to know

Given this, I hope you position your speakers extremely accurately and do not move your head more than about 1/2 a degree when listening. Someone really should invent an audiophile chair with head-clamp and resonance damping!

 

Well, yes I'm unhappy because I see you don't understand why people react negatively to your postings. This has nothing to do with Hifi nor what you beleve in and about what you are happy about.
Yes, it is very sad that you don't understand this..

 

I am not ashame of reading cientific books from which I can learn proven facts. Everything about sound physics has been studied long, long time ago.

As for Audio there really isn't new concepts since fourty or thirty years ago, just new misconcepts.

What concerns me most is knowing that some manufacturers don't read sound physics books... because if they did they would know that stereo is impossible without accuracy.

What you haven't realized yet is that better accuracy means better stereo image independently from where you are positioned.

What Tube Dude's amp did and what the Rotel 1062 do is taking the sound completely out of the boxes in an huge soundstage where we can localize without any effort every single sound source as a whole. With some records the musicians are in fact in the room with you... that is ultimate accuracy.

 

I take it that by "some manufacturers" and "you" you don't mean me.

After all, there's no way that you could know what I have or haven't read or what I have or haven't realised.

If, on the other hand you are referring to me ...

Don't be so bloody cheeky, Sonny.

 

How does a accurate 2 channel system reproduce the stereo image independent of the listening position? The whole concept of a two channel system is dependant on the listening position being between the two speakers.

Have you ever heard a REALLY good system BD? I am beginning to get the feeling you have no idea what a good Hi-Fi can sound like.