[AJinFLA]

My question was not whether you could measure a difference but whether you heard any.  Do you ever trust your ears? 

Eye witness testimony has been shown to be quite unreliable with the advent of DNA testing (yes, those ghastly "measurements"). Is it because people don't trust their eyes? Or is it because scientific testing is more reliable and repeatable? A test tube not caring about emotional or psychological responses that can lead to error.
Do you think "Ear witness" testimony is more reliable than repeatable scientific measurement? Or less reliable?
You mention Dr Geddes (Physics/Acoustics) as the electrical measurement only man. Why no mention of his partner Dr. Lee, whose specialty is Psychology/Audiology?

cheers,

AJ

[JoshK]

My question was not whether you could measure a difference but whether you heard any.  Do you ever trust your ears? 

Eye witness testimony has been shown to be quite unreliable with the advent of DNA testing (yes, those ghastly "measurements"). Is it because people don't trust their eyes? Or is it because scientific testing is more reliable and repeatable? A test tube not caring about emotional or psychological responses that can lead to error.
Do you think "Ear witness" testimony is more reliable than repeatable scientific measurement? Or less reliable?
You mention Dr Geddes (Physics/Acoustics) as the electrical measurement only man. Why no mention of his partner Dr. Lee, whose specialty is Psychology/Audiology?

cheers,

AJ

AJ,

Dr. Lee is his wife more specifically. I met the two of them. 

It isn't that I don't trust measurements or that I trust ears over measurements.  The question becomes even though it may not be a most reliable source, is there no information in why many hear, even when measurements can't find it?

I still trust my ears over measurements, because it still hasn't been shown that measurement measure what we hear.  Why do we hear so much differently? Why were SS amps that measured perfect in the 80's so damn ghastly?  We often measure in the freq domain, show me measurements in the time domain (I know phase has some of it) which are ears have been shown to be more sensitive to that freq dom. 

[Dan Banquer]

"How about this: which do you trust? Your common sense experience of the world, or classical mechanics? The two in general aren't the same "

My experiences in audio tells me they are very much the same. I would say instead of classical mechanics classical electronics.
               d.b.

[Dan Banquer]

I meant with cables....

See my previous post.
             d.b.

[WEEZ]

  All I had to do was mention wires and this thread went off into a sh*t storm  

I don't hear 'break-in' with some components. I do with others. I don't care to measure it, I'll leave that to scientists. And whether it's real or not...even when I (we) hear it...it only takes a few days and it's over with fer crissakes. Guess I (we) had a head cold for a few days. Or not.

sheesh

[AJinFLA]

Actually I think this thread has been quite civil. I will bow out now however, as they are apt to continue ad infinitum, unless otherwise terminated .

cheers,

AJ

[JoshK]

I meant with cables....

See my previous post.
             d.b.

If you meant that cables had to be used to hear your system, then yes you answered my question, otherwise you didn't.

[Daygloworange]

In the time domain is where I think may lay some things that are worth looking into. Phase and time arrival issues are huge in how we perceive a stereo image.

In the studio we goof around with stereo samples. We can shift one of the signals (L or R) by tiny fractions of a second. When you play them back, you can hear differences in soundstage, attack, Eq (due to comb filtering). Not necessarily all at the same time, or every time, and with every minute shift. And more so with some sounds than with others.  The beauty here is that you can A/B them rapidly. ( altered vs non-altered ).

Considering the effect vs the minute differences in time arrival modifications, I find it more than scientifically plausible that these effects actually do exist in measurable reality, and not just in our minds.

Given that listening in stereo you are not listening to one source. You are listening to two sources arriving at you. A shift somewhere, somehow could have a similar effect. Our hearing has the ability to localise sounds 360 deg around us, I'm not sure what the the efficiency pattern would be, but I know that it does diminish with age, along with our ability to hear higher frequencies.

Cheers

[LightFire]

    ABX tests will show there is no difference.

This is incorrect -- ABX tests cannot demonstrate this.

Of course it is correct. Would you let me know why do you think it is not?

[markC]

wow, this thread has exploded over the last day or so.
Guess I'll give my impressions for what they're worth. As far as cables, wires, connectors go-never heard a difference. Component upgrades such as caps resistors etc. heard a defence immediately- not so much after time.
Speakers, to my ears, are a definite "change in performance" device. I have built several speaks over the last 7-8 years and can confidently claim that I indeed DO hear a difference in their performance after x hours of use. Mostly in the bass region, which in almost all experience becomes more solid and brings less attention to itself.
As far as equipment warm up goes, I hear a smoother more full sound after a 15-20 minute run than when it's first turned on.
Hey-That's what I hear and way back 8 pages or so ago, that's the question that was asked.

[JohninCR]

    ABX tests will show there is no difference.

This is incorrect -- ABX tests cannot demonstrate this.

Of course it is correct. Would you let me know why do you think it is not?

Because they don't achieve the "correct" results in the eyes of believers.  I don't understand
the attitude.  If I thought I heard a difference, I'd want to find out definitively and understand
why, especially since it's a common topic of argument.  This "I believe because I think I heard
a different sound 100hrs of playing time earlier" just doesn't hold water.  Even 2 minutes later
after you changed the cables yourself doesn't hold up.  Just get yourself 2 cheap pairs and
confirm that you can't hear a difference when they're new.  Then just have someone else do
blind switching for you and see if you can identify with some degree of accuracy which is
burned in and which isn't.  IMO it's always better to know the truth, and regarding this topic
it doesn't even take any of the fun out of getting new toys, although it may help you find out
if a vendor just "sold you a bill of goods".

[JohninCR]

Dayglo,

I don't follow the point you are trying to make.  Are you saying that yes, we are able
to identify small changes in the time domain with immediate switchability, with which I
would definitely agree.  If you're saying that burn-in may result in time domain changes,
then that should be measureable.

If using a component changes the properties of the dielectrics through heat, etc., I can
buy into that, however, when you're talking about small changes in the speed of electricity
that approaches the speed of light, I don't believe the effect is possibly audible.

[Daygloworange]

Dayglo,

I don't follow the point you are trying to make.  Are you saying that yes, we are able
to identify small changes in the time domain with immediate switchability, with which I
would definitely agree.  If you're saying that burn-in may result in time domain changes,
then that should be measureable.

If using a component changes the properties of the dielectrics through heat, etc., I can
buy into that, however, when you're talking about small changes in the speed of electricity
that approaches the speed of light, I don't believe the effect is possibly audible.

JohninCR,

I'm just giving you some examples of how very minute shifts can affect stereo perception. How it can cause the effect of soundstage opening up or changes in frequency response. I'm not an electronics expert or a physicist, but I'm just putting this info on here hoping someone with more knowledge than me could chime in or use it to help explain the phenomenon we are discussing.

I have read on threads before about this topic, but it usually is about testing on a bench. I'm not sure if they take into the account effects on time arrival and/or phase between two channels. When it comes to speakers, as far as I know, they test/measure one at a time....we don't listen to one channel.

You don't have depth perception with one eye closed. You don't have the same sense of localisation when listening to one speaker.

So my whole thing was, with the effects on sound, when shifting one side of a L/R stereo sample being clearly audible when we are talking fractions of a millisecond, then ostensibly, with the way current flows in, around, on the surface of wire/ at different frequencies or through different electronics, there could be perhaps minute time arrival issues at different frequencies with a burnt in set of IC's ( or SC's, capacitors, etc..) versus a brand new pair, which could be an explanation for the phenomenon we refer to as burn in.

Cheers

[avahifi]

For what it is worth, in the rare event where we have replaced a complete audio board in an older piece of equipment here for service, we have never heard, or had any feedback from a client, that the two channels no longer sound exactly the same.  As long as both channels have the same active devices, the same parts values, and both are working the same, it appears that the fact that the parts on one channel have had many years of "burn in" time and the other channel has all fresh never used parts is not making significant musical differences. This seems to be true even when the actual parts brands and physical size has changed.  Capacitors, for example, keep getting smaller and smaller for a given voltage and value rating over the years.

Frank Van Alstine

[Dan Banquer]

I meant with cables....

See my previous post.
             d.b.
[/quote


If you meant that cables had to be used to hear your system, then yes you answered my question, otherwise you didn't.

I answered your question.
         d.b.

[Dan Banquer]

On any well designed solid state unit there should be no significant measurement changes. The only thing that has any real aging properties are electrolytic capacitors, and after 500 hours of use they should be very close to original condition.

This does not answer my question, which specifically asked if you have ever measured the electrical properties of a brand new component upon installation, and again after several hundred hours of use to determine what changes have occurred. You propose that there should be no significant measurement changes, yet as you admit below you have not done the testing required to support this theory.

As far as my own products are concerned I have never measured or heard much of anything in 5 or 10 years of age. At fifteen years it's time to replace the electrolytic caps.

Since you have not measured in your own equipment what you are asking me to measure, you cannot prove your theory any more than I can prove mine.

Can you be specific about what equipment I will need to acquire, borrow or rent to conduct the appropriate tests, and can you also please tell me what specifically to test? I would think measurements taken at the outputs of the component in question would do the trick, yes?

[/quote]

I think I answered your question. Please re read what I said. If you are interested in doing further studies of aging equipment I would like to encourage you to do so. If there is a change it should show up in noise, frequency response and distortion measurements. Most of what I have found is directly due to the aging of electrolytic caps. I have not found much of anything else, with the exception of a 20 year old Yamaha tuner that needed re alignment after 20 years and the work I put into in it. I would consider that pretty normal. if you own tube gear than I would recommend that you measure the unit with new tubes and the same tubes after X (100 hours? 200 hours?) amount of hours of use. I am practically ready to guarantee that you will be able to measure a difference.
                      d.b.

[JohninCR]

As far as I'm concerned Frank and Dan's input settles the matter.  Thank you gentlemen.
The earth is basically round after all.  Though I've seen this topic numerous times, I think
Mr. Van Alstine's post addresses the matter as efficiently as I've seen, and does so in a
way that should put a ? in the mind of even the most diehard believer.

To all of you believers, those on this side of the fence don't think you are crazy or that you
are "hearing things".  Instead we understand that there are perfectly valid explanations for the
perception that the sound changes over time.  One or more posters mentioned "trust your ears",
and my response is yes use your ears, they're wonderful instruments.  Just be careful, because
our ears/brain do play tricks on all of us.  eg  Think about this, without trickery the wonderous
stereo image we hear wouldn't be possible.  Instead we would hear 2 slightly different versions
of the music coming from the 2 sound sources.   

[Kevin Haskins]

Mr. Banquer, what equipment would I require to measure changes in noise, frequency response and distortion, and where would these measurements be taken?

Since no one in this discussion has done measurements, we can not conclude anything at this time.

Praxis would work.    Where they would be taken is via the output of the device being measured. 

[rajacat]

Let's say that you are auditioning two different amplifiers. One has superior specs. according to state- of- the -art testing equipment. You notice that I say state-of-the-art testing equipment because the technology is evolving as is audio equipment. Let's suppose you find that amp. hard to listen to compared to the other amp with the inferior specs. Which one would you purchase?

I think that the current testing technology gives you a nice baseline to work with but there are probably aspects of sound quality that the current test equipment does not address therefore many, if not most people, will base their choice (if auditions are available) on perceived sound quality rather than specs. that are probably incomplete as far as giving a true picture of the real sound quality.

[Daygloworange]

JohninCR,

With all due respect, I wouldn't considered the matter resolved. It's really not that simple. Believe me, I wish it were. I'm a naturally inquisitive person with an open mind.

But having said that, I have experienced personally. too many things to just write it off. I agree that we will probably never resolve it fully in this thread or any other, but it does bring out new info and examples, which are of value to both schools of thought on the matter.

On the psychology of perception, I've seen perplexing examples of people thinking they heard something, or people not hearing things that were clearly there and heard by others when I was a student studying classical, that leaves the door open and wants me to enlist others to share in their findings. I could share lots of examples and might if this thread keeps on going, that are food for thought.

I am by no means argumentative just for the sake of it, I just really enjoy reading other peoples thoughts, opinions, and experiences, no matter what perspective they are coming from. If the issue was a non issue, then people wouldn't even read or contribute to threads such as these.

Cheers