Looks good, I found the biggest difficulty is measuring the few milliOhms of resistance.

Maybe a model number,  I will look it up.

John... 

To Pluto and all,

Before I set about the ABX design it  would be good to know what we are going to compare, if it were interconnects then light duty gold flashed contacts may be the best, however if we're talking speaker cables then high current silver contacts maybe better.

To pluto, can you e-mail me with an in depth requirement of an ABX switcher, although the workings woud be almost entirely in software, the hardware has to cover all eventualities.

John... 

can you e-mail me with an in depth requirement of an ABX switcher

I will get something to you over the weekend, althought the posting I did last night (10/10/07 22:05) in this thread is reasonably precise.

Considering the limits of what we can reasonably get done in an afternoon, I was thinking of comparing an example of cheap with expensive(ish) speaker cable, interconnect and mains cable. AVR will get the samples in from manufacturer(s) and of course not tell you what they are until afterwards. The equipment will be screened off and we'll do three separate ABX tests for each of the cable types. How does that sound?

BTW, the venue will be Cambridge Audio's listening room, a short walk from Borough tube.

Dave

If we only have one ABX switcher, then I think it only practical to test one type of cable.

From the design point of view interconnect would be the simplest, speakers next, mains almost impossible.

How about a vote - interconnects or speaker. 

OK on the venue.

John... 

Perhaps one for the future, (and forgive me if you've seen this before!), but why just test cables blind.....

http://www.matrixhifi.com/ENG_marco.htm

and for a cheapy ic, how about a 30 year old freebie that came with a sony cassette deck?

How about a vote - interconnects or speaker.

Dave - as I believe John Fisher is going to build the ABX unit I described a few posts back, perhaps his opinion on what is most practical in the time available would be a good starting point.

That said, to throw my two pence in, I think speaker cables would make for a more interesting first attempt.

No you don't.  A switch box would be detrimental and would influence the result.

Hi

I'd be interested if it is on a Friday as I have to work the rest of the week! Borough is fine.

I think limiting how much we try is a good idea as it takes ages to test cables. It took me a week to buy an interconnect as they all sounded good but some better with different material. I also found that doing quick a/b tests just confused things so much that you couldn't be sure what appealed. I think you have to play a selection with one cable at a time to get the measure of it.

We should maybe limit songs to about 5 or 6 and get a broad range to cover classical, acoustic, female vocal and heavy rock.

Slawts

A switch box would be detrimental and influence the result

...and the five minute gap required to change cables would not? Unless your auditory memory is well above the norm for homo sapiens, that gap will prevent proper evaluation.

IF [a very large and sceptical IF] any degradation is added by the switching components, it will affect both test specimens equally. Or are we at that level of audio mysticism where high quality relays only affect the sound of expensive cables, whilst leaving cheap cables unmolested?

Slawts said,

I also found that doing quick a/b tests just confused things so much that you couldn't be sure what appealed

Remember, the purpose of an ABX test is NOT to determine which "appeals" most. The purpose is simply to determine whether, or not, a discernable difference exists between the objects under test. Nothing more.

'Are you up for it Christopher?'

Would depend on my work schedule which I can't alter unfortunately.

I think if you're going for it, you should go all the way and go for as much of a loom as possible.  Two comparisons, one silver and one copper with very limited objectives - to basically determine whether there is an audible difference.

Listeners having a go one at a time (half a dozen people in a room doesn't work).   Probably a minimum sample size of ten people or so.  With each one, you would change the order in which the cables were demonstrated.  Ideally noone with an anti cable axe to grind should be on the listening panel because that would statistically skew the results.

If you had two identical CD players, you could just switch inputs on the amp.   I'd suggest the CD players should be used to test one interconnect and one mains cable at the same time.  Speaker cables would be a problem because the subject could see what would be being used.

This has actually been done before.  The Hifi+ attempt at this was actually pretty good although the sample was too small. 

Considering the limits of what we can reasonably get done in an afternoon, I was thinking of comparing an example of cheap with expensive(ish) speaker cable, interconnect and mains cable. AVR will get the samples in from manufacturer(s) and of course not tell you what they are until afterwards. The equipment will be screened off and we'll do three separate ABX tests for each of the cable types. How does that sound?

BTW, the venue will be Cambridge Audio's listening room, a short walk from Borough tube.

There's no reason why switching cables should take longer than about 30 seconds - even speaker cables if they're terminated.

The curtain would also cover the speakers while the cables were being changed, and we can have them masked so you can't see them running into the back of the speaker.

I know it's not the first time this sort of test has been done, and it certainly won't be the last, but I for one am very interested to see the results that come from cable sceptics and cable believers hearing exactly the same information.

Sounds reasonable.  

I would strongly suggest that one of these should be a pure silver loom from mains cable through to speakers.  If you have three sets of silver plated copper then people will be listening to similar compositions on an unfamiliar system/room & it might not be conclusive. 

Dave what could be more simple than to have a A@B test of two cables, one set expensive, the other fairly cheap, if we carry on like this with talk of switch boxes milli ohms, conductivity,resistance,etc etc etc,.The whole point of this test,is to try and hear a difference in the two set ups,not whether there,. this thickness or that thickness, why in heavens name do people have to complicate things,just get two lots of cables and change them over,surely after two or three minutes changeover we would be able to remember what the previous sound was like.

Mick.