Sound Quality Vs. Measurements

[M Gregg]

When an average person goes for buying HiFi, he has no time and possibilities to become an expert before that. He most frequently proceeds from a budget available, from advertising, from how equipment looks like. Only few of HiFi owners start to look for something better, and eventually become an audiophile.
I personally proceed from a supposition, that the present forum is attended by audiophiles (or some persons from related industry branches). I also guess, that audiophiles and industrial designers could have different motivations. Therefore so different poits of view are supported.

I agree,

However I do believe that for sound to be "Good" then it should not sound electronic..I find that most people can tell "Good" sound.(Not all).
Women for some reason seem to hear things in a different way(Audiophile).
Industry can be motivated for profit etc.

Regards
M. Gregg

 

[jan.didden]

The answer is simple: when people buy more and more of audio devices of the same functions that means they are not satisfied yet.

But, Anatolyi, it's also a matter of searching for that elusive Great Sound. It is very difficult to have a clear idea, let alone to express it, what it actually is what you are looking for. The result: buying and swapping and never be satisfied. It is not so much a matter of not having the right equipment, but also of having an elusive target.

jan

 

[Wavebourn]

But, Anatolyi, it's also a matter of searching for that elusive Great Sound. It is very difficult to have a clear idea, let alone to express it, what it actually is what you are looking for. The result: buying and swapping and never be satisfied. It is not so much a matter of not having the right equipment, but also of having an elusive target.

I agree with you Johannes; but I have to add that even when the target is right and real means are very confusing and contradictory. According to my own experience, it is like solving equations with multiple variables in order to balance on an edge of a needle.

 

[tvrgeek]

If time permits, a new schematic incorporating all of these changes would be helpful for us.

Happy to oblige. This does not have the transistors I would pick, or even the Exicons I have now. Just the topology changes to keep comparisons in the fruit family. Of course, not having models for the parts I would pick has a lot to do with it. Considering bang for the buck, the VAS current mirror is where it is at.

 

[bcarso]

But, Anatolyi, it's also a matter of searching for that elusive Great Sound. It is very difficult to have a clear idea, let alone to express it, what it actually is what you are looking for. The result: buying and swapping and never be satisfied. It is not so much a matter of not having the right equipment, but also of having an elusive target.

jan

And as they say, the journey is the destination.

For some reason I'm reminded of the joke about person A asking of a mutual friend B what she might get as a gift for person C. B says, How about a book? And A says, No. I think she already has a book.

And then the variant in the record store. Having been told that the recipient likes classical music, the clerk suggests Mahler's 5th Symphony. No, says the customer, I think she already has a 5th symphony.

 

[ThorstenL]

Hi,

In the end, it seems to me that I have true high fidelity if a trained musician can sit down and say: "That's a Les Paul, not a Gibson guitar.", or "That's a Yamaha, not a Steinway piano".

For me it is about being able to tell if the cymbals on the drumkit where Paiste, Zildijan or others... I'm not great on Piano, I can tell e-guitars okay, some Amp's too.

I personally played and liked a no-name, semi-home-made (I bought the guitar 2nd hand, it was sturdy enough to handle steel strings and I electrified it) electro-acoustic guitar with a piezo under the bridge and a single electrical pickup and a condensor mike plus J-Fet electronics. It had actually still quite a lovely Acoustic tone (with a bit of bite from the steel strings) and very variable (but always électrocoustic) tones from mixing the various pickups.

I never was really any good playing it (or at least not as good as making it maybe), so I eventually gave it to the guitarist of a band I worked with, who kept playing it for quite a few years when he was not trying to be Jimmy or one of the other Axeman and loved what it could do for songs that needed an acoustic touch.

With all the modern modeling guitars and amp's it becomes hard to tell...

There's too much theory floating around, it seems to me, and too little practice.

It's the curse of these modern times. Theory before practice, because in theory there never is any difference between theory and practice anyway...

I always though theory, i.e. science, was invented to result in something practically useful? Not to be an art unto itself, for its own sake.

That was long ago, in the Renaissance and age of Enlightenment. Modern Science (in audio and elsewhere) resembles the very rare and unusual Oztralian (I'll throw an extra shrimp on the Barbie) Oozlum Bird (it's habit of flying in ever decreasing circles until it flies up it's own rear orifice and promptly disappears is said to add to it's rarity).

Ciao T

 

[tvrgeek]

I agree,

However I do believe that for sound to be "Good" then it should not sound electronic..I find that most people can tell "Good" sound.(Not all).
Women for some reason seem to hear things in a different way(Audiophile).
Industry can be motivated for profit etc.

Regards
M. Gregg

Agree in that most people can hear the differences in sound quality. The realization is that most will not pay for it. Priorities. I have zero skill in producing music of my own, so I rely on reproductions. Even the cheapskate I am, I pay a lot for music.

The end result is the big box home theater customer (99% of the market) is buying for features and price. They are "sold" the features and shop the price. We are a small segment my friends.

 

[Wavebourn]

Hi Thorsten;

here is an example, Andrew Krylov exactly made a guitar like yours, with both piezo pickup and condenser mic with JFET inside.

http://wavebourn.com/music/akrylov/samples/aksample01.mp3

 

[Wavebourn]

And as they say, the journey is the destination.

For some reason I'm reminded of the joke about person A asking of a mutual friend B what she might get as a gift for person C. B says, How about a book? And A says, No. I think she already has a book.

And then the variant in the record store. Having been told that the recipient likes classical music, the clerk suggests Mahler's 5th Symphony. No, says the customer, I think she already has a 5th symphony.

It is not so simple... More questions: who, where, and when performed?

And one more related: who recorded, what kind of equipment used, what format?

 

[tvrgeek]

Hi Thorsten;

here is an example, Andrew Krylov exactly made a guitar like yours, with both piezo pickup and condenser mic with JFET inside.

http://wavebourn.com/music/akrylov/samples/aksample01.mp3

I like that.

 

[dvv]

It has 2 MOSEFTs, my Serbian cousin!

Aaaaahhh! I breathe again!

 

[Wavebourn]

Aaaaahhh! I breathe again!

So what? You have a schematic. How can you get sound quality and measurements from it?

 

[gk7]

...
Damping factor is a synthetic measurement unrelated to anything real. A damping factor of 10 or so suffices to minimise the frequency response variations due to varying speaker impedance and the so called "damping"of the woofer is limited by the Speaker DCR. Hence the true Damping factor rarely reaches 2.
...

I have no reason not to believe you, but when I insert a 0.46 Ohm resistor
between my amp and speaker (thus lowering the damping factor from
something > 50 to something about 17) the difference in the bass region
is _very_ clearly audible. How can this be the case if it´s never more than 2 ?

 

[gootee]

I have no reason not to believe you, but when I insert a 0.46 Ohm resistor
between my amp and speaker (thus lowering the damping factor from
something > 50 to something about 17) the difference in the bass region
is _very_ clearly audible. How can this be the case if it´s never more than 2 ?

But what other system changes does the resistor also cause? Is there a crossover downstream?

 

[scott wurcer]

Damping factor is a synthetic measurement unrelated to anything real. A damping factor of 10 or so suffices to minimise the frequency response variations due to varying speaker impedance and the so called "damping"of the woofer is limited by the Speaker DCR. Hence the true Damping factor rarely reaches 2.

Don't spoil the party. Simple experiment, take a woofer and a mic and record a thump with the voice coil hard shorted and open. That's the most difference you get from amplifier damping.

 

[bcarso]

But what other system changes does the resistor also cause? Is there a crossover downstream?

Astute. The 460 milliohms could be having a significant effect on the overall frequency response, which could be difficult to assess as due just to damping of the woofer.

Even if the resistor were placed in series with the woofer driver alone, it will still be reducing the woofer voltage and thus the overall frequency balance of the system.

On another note: if damping factor were something where more was always better, we can contrive an amplifier with a frequency-dependent negative output impedance, and back out the voice coil resistance. The voice coil temperature will change with drive history and possibly put us on a slippery slope for stability (against oscillation when colder, more damping when warmer), but this can be accomodated in real time via additional tricks.

However, is more damping better? I saw some short piece a while back in which, after some fairly non-controversial remarks, the writer said that a highish output Z for the amplifier helped the speaker "sing" in some supposedly beneficial way

As with so many things, I tend to give the benefit of the doubt to the speaker designer, at least to begin with.


Brad

 

[Wavebourn]

Don't spoil the party. Simple experiment, take a woofer and a mic and record a thump with the voice coil hard shorted and open. That's the most difference you get from amplifier damping.

Now please record the difference between shorted and loaded on 0.47 Ohm resistor.

 

[CopperTop]

Astute. The 460 milliohms could be having a significant effect on the overall frequency response, which could be difficult to assess as due just to damping of the woofer.

So there's damping factor, and there's damping factor?

A 0.46 ohm resistor isn't a 'genuine' low damping factor, and its apparently large audible effect is therefore not a genuine concern. However, an amplifier that has a high output impedance, for any other reason, is always a 'genuine' low damping factor, and as a result is virtually inaudible..?

Is the term 'damping factor' not really that informative, then?

 

[benb]

This damping talk brings up a question. Are speakers usually designed with the assumption they'll be driven only by an amplifier with a high damping factor? Are they ever tested at lower damping factors as part of the design/evaluation process? With all the stuff in crossovers as well as driver resonance, this could have a substantial effect on frequency response.

I'd think they should be tested with a range of driving impedances, if for no other reason than to find out what happens. An unknowledgable customer may use 100 feet of 16 gauge to connect the amp to the speaker, with the total wire resistance becoming several tenths of an ohm. And then there's tube amplifiers, and furthermore the "current mode" amplifiers with much higher output impedance, making the damping factor much less than 1 so the speaker sees practically an open circuit.

 

[wahab]

A high NFB amp will have micro ohms output impedance at low frequencies
rising to millihoms at high frequencies.

A low NFB amp will have higher but less variable output impedance,
so for the case above of 2R output Z , it may well vary from about one
to five ohms in function of frequency , audio band wise.

The case of a serial 0.47R with a conventional amp will produce
a high but constant output Z in function of frequency , somewhat
different from a low NFB amp output Z figure.