Scientific proof to differences in sound quality

Posted by: Arye_Gur on 09 September 2001

I'm a member in a stereo forum in Israel. The members in this forum have different systems ranging from the cheapest home cinema systems to the top and famous manufacturers.
There are few kinds of approaches to HiFi - as some of the members are young and unexperienced and others are very experienced .
Few of the members are electronics engineers - and here is the question.
When members (even the most experienced ) are telling about a difference in the quality of sound because of a change in a component, the engineers are asking for a scientific proof for this change. If they think that there is no such an explanation, they calim that the change in sound comes because of a psycological effect of
the listener.
Two examples -
1 - The engineers are claiming that there is no way that an audio cable will be affected by the direction of it.
2 - There is no way ("it is against the phisical knowledge") that replacing the cable from the wall to an amplifuer will affect the sound .

Do you have an opinion about Psycological effects or scientific prooves about sound quality - and maybe about the examples above ?

Arye

Posted on: 16 September 2001 by bam
This cable crystal stretchy extrusion talk is all very well at explaining how a dc current may flow differently one way than another, but no one has addressed my earlier point that the music signal is a symmetical AC signal and so flows in both directions. Therefore it is by definition equally affected by both directions of the cable. Any takers on this?
confused
Posted on: 16 September 2001 by bam
Frank wrote:
"they found that mechanical isolation had at least as much impact on the result as the electronics in it! The casings do not change any electrical properties of the amplifiers and yet it's all important."

I disagree. What your ear hears is the affect of the electrical energy transmitted to your speakers from your amp. If the amp casing changes the sound then it also changes the electrical energy. If it didn't you wouldn't hear a difference (unless it's some bizarre reflected sound waves of your amp box...but let's not go there). If Naim believe casings change the sound but they don't believe they change the electrical properties of the circuits then I'll eat my hat.

BAM
(someone lend me a hat)

Posted on: 16 September 2001 by JohnS
quote:
the music signal is a symmetrical AC signal and so flows in both directions. Therefore it is by definition equally affected by both directions of the cable. Any takers on this?

Interesting point bam. As this is so, why do Naim SNAIC cables have directional markers on them? I'm sure some of the forum members have tried their SNAICs the other way round just to see if there is a difference. Anyone?

-John

Posted on: 23 September 2001 by jpk73
The very simple answer is: "What your ear hears is the affect of the electrical energy transmitted to your speakers from your amp". So the energy is not only going forward and backward, there is also something going from the amps to the speakers, ist't it! Otherwise the energy would stay in the cable and you would hear nothing... ;-)

You can take a bottle and fill in water. You measure all properties of that water in the bottle, then you vibrate the bottle in a certain way and measure the water again. Same thing happens to the cables: as I understood they vibrate the cables hanging down, and that is also the direction they mark the cables. The energy has to pass the cable as smooth as possible, the energy then will be given to the air by the speakers and finally reach our ears. I am not talking about the molecules which transport this energy by going forward and backward...

I hope you can understand what I try to say!

Best wishes from Jun

Posted on: 23 September 2001 by bam
Jun,
I think I understand what you are saying: that there is a net transfer of energy in one direction - from amp to speakers for example. Agreed. Then you say that because the energy is transfered in one direction that the direction of the conductors matters. Disagree.

Current flow in either direction in the cable causes a net transfer of energy to the speaker. Half the time the current flows one way and half the other. In both halves energy is being transfered to the speaker.

I think the earlier question about the orientation of the "directional" conductors is really key. Current flows in a loop - the audio interconnect provides a conductive loop. The current flows around the loop in alternating directions. Once this is recognized it becomes a challenge to decide which orientation to choose for each half of the loop.

I really don't see how the mfrs of "directional" interconnects decide which orientation to choose for each conductor. How are the two conductors in a speaker cable oriented? And what about coaxial interconnects? Are the braids directional too? I'd be really interested to hear from anyone who knows the answers to these questions!

I would also like to hear from anyone who can swear to be able to hear a prefered direction for an interconnect, with statistically significant repeatability under blind conditions, and across a few cables so as to mitigate the affects of connector contact differences. There must be some of you who have done this.

I find this fascinating and I'd really appreciate an explanation for it if for no other reason than to expand my education.

BAM