bayermar said:
True. The problem with any kind of auditions is that the ear/brain gets tired quite fast. You may be able to get a higher number of meaningful samples only if you spread the test over several days or even weeks. Do you expect audiophiles to have such determination to prove their position. For what?
Hi analog_sa,
yes, I agree that a meaningful test would be very time-consuming and hard to perform.
I just wanted to point out that one has to be careful with results of listening tests even if they are done blind or double-blind if the number of repeats is small.
The result might look very clear, pointing to one sample as being superior to the other, but statistically there is no difference.
Martin
yes, I agree that a meaningful test would be very time-consuming and hard to perform.
I just wanted to point out that one has to be careful with results of listening tests even if they are done blind or double-blind if the number of repeats is small.
The result might look very clear, pointing to one sample as being superior to the other, but statistically there is no difference.
Martin
bayermar said:Hi Panicos,
maybe I am missing something.
In a DBT with two cables you would get 50% success rate by pure chance.
Do be sure there is any audible difference you would need a statistically significant higher success rate (>50%).
Although this is statistically not sound, 50% success rate would rather indicate that there is no difference in sound - just imagination (and therefore guessing).
If I got your experiment right, you have three repeats with six samples (two cables - three times). This is a very small number to do a statistical analysis.
It would still be interesting to see the results (numbers) of each experiment in order to get an idea of the degree of confidence of your results.
Sometimes things look very biased in one direction but statistical analysis reveals normal distribution "by chance".
In "biological" experiments people usually ask for ~95% confidence to call it statistically significant.
My
Cheers,
Martin
Hi,
Yes it was 3 times each cable.We knew that it could not be a perfect test.We have decided to have long time with each cable so at least we wouldn't have an easy excuse in case of failure.In my case the difference was obvious in specific areas where I believe my hearing is more sensitive.That is on lead guitars and Gilan's voice,where my effort at the time of tuning my system,was to achieve the smoothest tone possible with this record.(and others of course).This recording I consider as one of the best in rock music,the sound and mixing engineers have achieved a near perfect balance between his voice and all instruments.I always refer to this record when I want to check something and it is always helpful.As for the statistics I have no doubt that you are possibly right.This senario however was not our task.Our task was to see if,under some pressure(by the fact that we couldn't see which cable we were listening at), which normally is not applied when someone wants to choose between two cables,one can finally come to a helpful conclusion.
rtsang: I will take from your post the example with the headache🙂 I take a soluble drug(aproved of course) when I have a headache.In less than 15 minutes I feel great.🙂 )Many people that have tried it have problems with their stomach.On the other hand,when I was at a friend's house and asked for something for headache,he gave me an again aproved one,and in ten minutes we were on our way to the hospital.The damned thing had almost killed me.What I mean by these examples-and are true-is that I don't care about the "correct statistics" that lead to the aproval of both drugs.I took my "test"and now I know at least what not to take🙂
I have gotten a good laugh and headache from this thread...
I have to say that cable is only a small part of the discrepency...
The capacitance is tiny has no contribution..
The wire inductance plays a role durring transient response, which is basically all the time in music...since the dI/dt of the AC mains current times the series inductance can be significant to the line droop at the amp... when the B+ droops so does the performance dynamic response..
I found the biggest contributor to be the contact between the plug and receptacle.... You have the cleaniness of the receptacle contacts which are not really visible many are corroded or blackened over the years... The contact resistance based on the contact pressure...The thicker plug blades usually get better contact pressure... This ohmic contact point may be small, but durring high current demand it may produce droop....
So to really eliminate this and are serious then you would "HARD WIRE" your equipment to the mains, atleast the high current stuff like power amps...
Combine the ohmic contact resistance of the receptacle to the plug blades with the series inductance of the cable times the dI/dt and you can have some significant mains droop at the amp.
In solid state amps or tube amps this can affect dynamic performance.
Chris
I have to say that cable is only a small part of the discrepency...
The capacitance is tiny has no contribution..
The wire inductance plays a role durring transient response, which is basically all the time in music...since the dI/dt of the AC mains current times the series inductance can be significant to the line droop at the amp... when the B+ droops so does the performance dynamic response..
I found the biggest contributor to be the contact between the plug and receptacle.... You have the cleaniness of the receptacle contacts which are not really visible many are corroded or blackened over the years... The contact resistance based on the contact pressure...The thicker plug blades usually get better contact pressure... This ohmic contact point may be small, but durring high current demand it may produce droop....
So to really eliminate this and are serious then you would "HARD WIRE" your equipment to the mains, atleast the high current stuff like power amps...
Combine the ohmic contact resistance of the receptacle to the plug blades with the series inductance of the cable times the dI/dt and you can have some significant mains droop at the amp.
In solid state amps or tube amps this can affect dynamic performance.
Chris
cerrem said:
AH!!
The man knows. And extra to the ohmic resistance, I have had a diodic effect between contacts, and even between a bolted down spade and the plug bolt inside the amplifier. It gave a sort of distortion that had me looking for a long time .....
Cerrem,
Basically true, but measurements I did showed that the effect of practical wire inductance in interconnects and loudspeaker cable is also minute and will be inaudible. This naturally not with 30m of cable or longer! - normal domestic lengths.
Sure, why not?
High quality outlets with excellent contacts are relatively cheap and (at least here in the US) widely available at nearly any home center.
Me too SY.When I was reading some information for my mains connectors one interresting point was the manufacturers claim for the mirror finish of their connector's blades.This increases contact area too another important factor for better signal transfer.Have you ever checked with a magnifier the contact surface of the "high quality"connectors you are refering at?I have and in some cases contact between the two connectors is just like a sponge.In lucky cases this contact might be 20% of the already tiny contact area these blades can have.And I am very generous actually.
Careful about that. Mirror finish increases area but decreases contact pressure. You're less likely to get a gas-tight connection.
Contact presure has more to do with the blade materials chosen and not the surface finish imo,altough I agree with your comment.I would totally agree with you if a connector with mirror finished blades and one with more rough finish,were made of exactly the same material.So,we nearly agree that a really high quality connector must have solutions for both issues.
One more detail.Even made with the same blade materials the contact presure would be the same,so,I would prefer the one with polished surfaces for their larger contact area.After all no one plays by pulling the plugs out of the sockets.
One more detail.Even made with the same blade materials the contact presure would be the same,so,I would prefer the one with polished surfaces for their larger contact area.After all no one plays by pulling the plugs out of the sockets.
omg... you guys are beyond reality
and have now put out a new opportunity for audio charlatains - high end wall sockets with oxygen depleted goldplated titanium leaf spring contacts. My marketing mind goes wild just thinking of hte opportunities.
Lord only knows what medical technicians (you know, the guys who run and service equipment that is required to do menial stuff like keep people alive, as agaist important stuff like reproduce noises...) would make of such esoteric drivel...
and have now put out a new opportunity for audio charlatains - high end wall sockets with oxygen depleted goldplated titanium leaf spring contacts. My marketing mind goes wild just thinking of hte opportunities.
Lord only knows what medical technicians (you know, the guys who run and service equipment that is required to do menial stuff like keep people alive, as agaist important stuff like reproduce noises...) would make of such esoteric drivel...
lol - polished surface?
I'd prefer one that had the surfaces absolutely parallel. All the shine in the world is no good if the contact point is only 1/100th of the surface area... (Yahoo!!!! - new marketing opportunity - parallelogram contact fittings - must take another look at my old Garrard Zero arm geometry...)
I'd prefer one that had the surfaces absolutely parallel. All the shine in the world is no good if the contact point is only 1/100th of the surface area... (Yahoo!!!! - new marketing opportunity - parallelogram contact fittings - must take another look at my old Garrard Zero arm geometry...)
A very little bit of sanity. Hospital grade plugs are design to be tight so they do not accidentaly get pulled out by who ever working around a patient in bed. There is a lot of traffic around a patient in hospital with many devices plugged into the and if any of them are accidentaly unplugged thee will be many problems which the hospital doesn't need. So the hospital grade plugs are made to fit tighter so they do not unplug if someone trips over, kicks or what ever.
Sorry didn't finish, hit the wong button. All hospital equipment is designed with proper A/C filtering to keep A/C nasty crap out. You would be amazed the amount junk on hospital A/C lines. What they care about is that the plug doesn't come out of the easily. I have first hand experiance since I fixed MRI, Cat scanners and many other types of medical equipment for almost 25 years. All this angst about power cords is entertaining to say the least.
In the old Cyprus dialect there is a very wise saying/proverb (maybe in other places too),I will translate it word by word because it is simple and really beautiful:
"I blind you and sell.You open your eyes and buy"
"I blind you and sell.You open your eyes and buy"
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