Hence I would not share you blanket conclusion, as the 'solution' will
depend on what we are trying to decide, and how we proceed.

Some changes can be detected electronically if the material remains in
the digital domain but once the sound has left the speakers there are
too many variables. For our Hi-Fi club we still use what for us is a
less flawed method of a-b comparison (preferably blind) on repetition of
a range of tracks followed by a longer term evaluation over the next few
weeks. I look forward to any proof that DBT for Hi-Fi has been
validated.

I'm afraid that "proof" isn't really something that experimental science
provides. Experiments provide *evidence* in terms of results which then
have to be assessed by understanding the experimental process actually
applied in the specific case. We can then decide what may have been
established as either reliable or unreliable. Science is not a matter of
"proof", but of testing to see if a hypothesis is supported or confounded
by suitable tests.
Sorry thought that the above was sufficient to be defined as proof.

When you say you use "a-b comparison (preferrably blind)" do you mean ABX?
I'd be interested to know what protocol and method you use and feel is
better than what Iain is proposing.
I cannot offer a better test protocol for Ian as I fear that they will all
be affected by the listener. I remember attending one of the London shows
where a supplier had an amplifier with standard capacitors and "special"
capacitors (Black Gates ??). The amp was connected to a pair of headphones
and you had a switch to change from A-B and once you had convinced yourself
if there was a difference a flap that when lifted showed which was which. I
also remember thinking that the "special" capacitors sounded slightly
clearer but at the price premium I was not about to try replacing all the
ones in my amp.

Our evaluation procedure is very rudimentary we start with the system (say
A) as is and listen for about 40 minutes, then listen to three specific
tracks before changing to component B We then listen to the same three
tracks. If a difference is significant it can usually be heard by all
attendies within the first few bars, however the opinion as to if this
represents an improvement is not always unanimous and not always the same
for all three of the tracks. If the general perception has been of a
benefit we usually listen for the rest of the evening in the B configuration
before finally returning to A to repeat the three tracks. In some venues
the equipment is in another room or away from the listening area allowing
some changes to be made or not made out of view of the listeners. Whilst we
try to keep the volume setting the same this is not always possible and
alcohol is partaken of . I am sure most of the differences we hear are not
due to component changes.

My big problem with the advocates of ABX/DBT is the opinion based on their
claimed tests that most components sound the same and that the results
obtained by these tests prove this. My experience is to the contrary in
that upgrades I have made in CD player, Amplifier and others still to my
hearing sound like upgrades and when the old component is slotted back into
the system I can hear the difference. I am not happy with simple a/b either
as this can easily create false positives and have found that if we spend a
lot of time switching from a to B and C backwards and forwards at the end of
an evening I am tired, I have not enjoyed the music and I struggle to tell
the difference between anything.
If an A/B listening session has been percieved a sucess it is most likely
that either a club member brought it with them or they are about to buy it
so I have been able to subsequently borrow it to listen at lesuire at home.
I can then listen for longer with my choice of music. I find most changes
are just subjective, it sounds different but rarely consistantly better and
is rarely worth the investment. What has however shocked me recently is
mains cables which I have always felt should make no difference at all. I
now however have a load of Kimber cables !!!

Regards Richard
Slainte,

Jim

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