In article , Iain M Churches
wrote:
Greetings to All.


Each member of the panel will be tested separately, and will listen to
each piece of music twice. On the first run there will be no changes, on
the second, the outputs will be switched at a TC known only to the
tester. The listener will press a cue marker, which will capture the
time code at which he/she perceived a change. This can then be compared
with the TC of the real changes.

I would prefer the *listener* to be able to operate the ABX switch as and
when they choose. The critical point is that they should have no
information beyond what they then hear as to whether 'X' is 'A' or 'B'. I
suspect that this would allow the listener to detect smaller changes than
the protocol you describe. Given the variability of music I also suspect
that a switch at some moments would take longer to notice than at other
times. Hence this may have an effect on the statistics that mean that a
larger number of tests would be required.

FWIW I am not really interested in "how long people take", but in their
ability to just detect (or not!). Hence introducing time as a factor is one
I would personally avoid as I fear it complicates the real issue.

However, provided there is no time pattern which the listener can predict
or deduce, your protocol seems OK.

I would also wish to have a lot of measured data on the performance of the
system to establish the level of any 'uncontrolled' effects which may
influence the results. Ideally, this would be in advance so that any
'contentious' points could be sorted out before actual listening tests.

Slainte,

Jim

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