Blind Listening Tests & Amplifiers

[fdegrove]

Hi,

I do'nt think the idea here is that you take everything you are told at face value, or indeed that you have to believe everything in every article, book, or paper.......the idea is to pick out the wheat and discard the chaff....and not to throw the baby out with the bath water...

Now, that's an idea even I can live with.

And to add insult to injury: I find the concept of wheat and chaff sorting quite healthy.
It takes both knowledge and experience to weed out the garden I'd say.

Cheers,

[mikek]

...No...i don't think anyone is saying everything sounds the same'......

....transducers certainly need time to bed in.........indeed the characteristics of 'speakers change with tempreture, humidity, etc......

...forget loudspeaker cables though, so-called 'high-end', multi-thousand dollar wires constitute one of the greatest frauds ever perpetrated on the gullible...period.

....and....all audio power amps. do sound the same given the conditions i painstakingly detailed earlier in this thread.....period.

nothing personal, plenty of hard unassailable scientific evidence...period.

[mrfeedback]

To an ant, the earth is flat.

Eric.

[Bratislav]

I think we have gone way too far past each other in this discussion.
It is clear to me that most subjectivists will kep believing whatever they are used to believe and use straw man methodology to discredit true objective tests.
Fine.

Lets just make one last thing clear here.

In order to detect differences between say two amps subjectivists will use their ears, I presume. Sixth sense might get involved but so far noone took it that far.
In order to hear something, eardrum must get excited. For that we need difference in pressure level (sound). This sound is produced by speaker, which no surprise requires some current in order to move (regardless of principle - dynamic, electrostatic, plasma, ribbon, piezo, you name it).
So let's agree here :
No electric signal (current flow), no sound. Nothing to detect (hear).

This is our Principle. With me so far ?

Now, the current is provided by amplifier. It can be shown that signal arriving to speaker terminals consists of two componnets : a perfect multiple of the input signal (this is what we want) and something else which we call distortion. This can be of harmonic nature, crossover (switching) residuals, intermodulation distortion, random noise, power supply residuals, cable induced distortions, RF pickup, parasitic oscillations, crap coming from the electric outlet finding the way through, you name it.
In order to HEAR the particular distortion (in order to reliably identify component in hand - the wholle amp, one resistor, cable, connector, whatever), this particular distortion has to be extracted by our ear/brain system from 1) useful signal and 2) all other distortions present.
By the way, component (2) will show easily if we substract the input signal (so called null test) in case of amplifier. But some even larger distorions will be also introduced by the speaker and the room.

One can argue till cows come home, but there HAVE been experiments conducted to establish what level is required for human ear to detect. This is pretty complex issue, as it depends on many variables (whether there is a correlation between signal and distortion) but bottom line is our ear is really NOT a very good detector. Its ability to detect sound is far, far inferior to our ability to measure electric signals. I mean FAR inferior. We can measure picovolts (1/1,000,000,000,000th of one Volt), and millivolts (1/1000th of a Volt) are dead easy. One millivolt at speaker terminal will not be detected by anyone's ear. That would be akin to plugging your Moving Coil cartridge directly to the speaker ! If you could hear that, you would save yourself great deal of money on expensive pre-pre, preamps and power amps too.

So question number one - how can one hear difference if we can't measure it ? (remember the Principle - no current, no sound ?)

Let's go further. Lets say that we CAN measure difference (and indeed we can, even in case of a single capactor or resistor changed, or a power cable swapped). In some case it will take quite ingenious setups to do this measurement, as differences will be minute. How much difference do we need to see before we can hear it ? It turns out, a lot.
In presence of loud sound (our "good" signal coming out of the speakers), ear's ability to hear tiny "bad" signal (distortion) diminishes greatly. Furthermone, it has pretty difficult task of telling THIS particular distortion from all the other ones. And those "other distortions" could, in say case of swapped power cable or say 3c resistor replaced by 75$ one, be more than MILLION TIMES larger than the distortion you're trying to hear. Can you really believe that you can hear THAT ?
I can't. No person who understands this can.

But feel free to disagree using whatever illogical argument you may invent now. I have nothing more to add really.

Bratislav

[ashok]

To an ant, the earth is flat.

Do you really know that ? How ?

Could it be that it is because they haven't found out yet or we don't know how to ask? Humans have been on Earth for over 50,000 years . When did we find out ?
Just a thought.
Cheers.

[ashok]

That first line should read 'Do we really know that ?'.
It just triggered my curiosity about how much we assume about the animal world.
Cheers.

[SY]

ashok, as humans, we're vulnerable to the Pathetic Fallacy.

[Pan]

"It is clear to me that most subjectivists will kep believing whatever they are used to believe and use straw man methodology to discredit true objective tests."

I believe what I believe, I know what I know, some things in life I´m uncertain about, and I do very much believe in well excecuted objective tests, never said the contrary.

"This is our Principle. With me so far ?"

Yes, I think I had a clue about that there was someting flowing to the speakers in that cable thingy, what you call it.. .current, oh yes, thanks!

"But some even larger distorions will be also introduced by the speaker and the room. "

This is the reason I say that many tests have been excecuted in the wrong way, often using less than SOTA speakers and using non treated rooms. I DO NOT BELIEVE I WOULD HEAR THE DIFFERENCES I TALK ABOUT IN SUCH A TEST EITHER.

I therefore have spent most of my money on the room and speakers. About $8000 on acoustic tools and loudspeaker parts, and much less on the rest of the rig.

"you would save yourself great deal of money on expensive pre-pre, preamps and power amps too."

I don´t use a pre in my rig because it colours the sound, instead I use a impedance optimized passive solution. The power amps I build myself to save money. Money should be put on speakers and acoustics where they make the biggest difference.

"So question number one - how can one hear difference if we can't measure it ? (remember the Principle - no current, no sound ?)"

We can not hear a difference if there is no measurable difference, that is clear as a bell. I know some people beliewe in "magic" in hifi equipment, plaese do not put me in that camp.

"How much difference do we need to see before we can hear it ?"

I don´t have exact numbers, but I expect not a lot. Since a CDP with low THD+N improves dramatically after a clock mod and amps with less than 0.05% and flat fr. response sound different, not to mention cables.

"And those "other distortions" could, in say case of swapped power cable or say 3c resistor replaced by 75$ one, be more than MILLION TIMES larger than the distortion you're trying to hear. Can you really believe that you can hear THAT ?"

First of all I don´t think it´s so much a question about $, but to answer your question, yes I can easily hear difference between loudspeaker cables and caps to the Accuton tweeter I use.

"I can't. No person who understands this can."

I wish I could invite you to my home for a listening session, you would be surprised what You can hear in my audio room

Happy listening!

/Peter

[Pan]

Originally posted by mikek
...No...i don't think anyone is saying everything sounds the same'......

....transducers certainly need time to bed in.........indeed the characteristics of 'speakers change with tempreture, humidity, etc......

...forget loudspeaker cables though, so-called 'high-end', multi-thousand dollar wires constitute one of the greatest frauds ever perpetrated on the gullible...period.

....and....all audio power amps. do sound the same given the conditions i painstakingly detailed earlier in this thread.....period.

nothing personal, plenty of hard unassailable scientific evidence...period.

About the "everything sounds the same" issue, I think you know what I meant.

Cables, agree with you expensive cables are the biggest "fraud" and I would never pay more than $30-40 for a pair. However that does not mean that there is no audible difference. Turns out we are lucky since excellent DIY solutions can be made for peanuts
The best cable I have had in my system is two pieces of unrolled copper foil inductor without insulation at a cost of $15. Sounds better than Flatline red dawn and AQ $1700 "frauds" (that actually sounded good)

To repeat myself, if two amps have truly identic behaviour under all practicall situation as reactive loads and different levels, then off course there would be NO audible diference. Since there are no two amps that are identical, there will never be two amps measure exactly the same. Now can we hear that is the question we have been beating to death here and off course that depends on how much the measured difference is.
Listening tests indicates that we hear much smaller errors than some have been made to believe and/or our measurments fails to get the whole picture (so to speak) when an amp drives a complex reactive load with complex program material.

This amps I have tried I can tell apart in a couple of seconds, that big a difference there is.

Audio Research VT100
GamuT D200
Pass Aleph 5
Zapsolute
Patriot V100
Gainclone
Holfi Integra and Audis
Luxman
Arcam

Maybe these manufacturers lies about the THD levels and the reason I can hear the difference so easily is because off high distortion. I suspect not though, but simply that a high resolving rig can and do differentiate between such low distortion amps as above.

Happy listening

/Peter

[carlosfm]

Please let me clarify my position, and as an example I can tell you an experience I had just a few days ago.
I went to visit a friend of mine in an Hi-Fi distributor, with some cables I made on my hand.
I asked him if we could compare my cables to some comercial designs.
He told me he was out of stock, but could get two examples from Wireworld.
One costs around 80 Euros, the other is their top of the range, costs around 1000 Euros.
He connected my cables and the 80 Euros ones from a cd player with two fixed outputs to a preamp.
I was with an excellent disc on my hand, by the way, to test this things: Joe Jackson - Volume Four (his last CD).
While playing, I asked him what was the cable it was playing right now.
He told me "it doesn't matter".
It ended up like a blind test.
Final results were that I liked my cable over the 80 Euros one (the difference were night and day).
With the 1000 Euros one I could hear some subtle sound I wasn't aware in the beginning.
My friend had the same oppinion, and he knew all the time what was playing.
So, I don't consider "golden-ear" myself, but I think I can detect two different amps.
But the best one for me can be the worst for someone, who knows?
Would I go to the trouble to measure all these cables?
Of course not!
By the way, the cables I made are UTP Cat.5 network cable, with some cheap gold-plated plugs, silver soldered.

nw_avphile, I really think you must be a saint.
You really have the patience to repply to all these people (me included).
But it seams to me you haven't learned anything.
I still need to know what music do you hear when testing an amp.
Elevator music?