Re: setting up ABX tests at home

Steve wrote:
> I want to set up an ABX test at home on different sources to see if I
> can hear a difference. I am doing this for my own education and fun -
> I don't want to start investing in SPL meters, switches gain
> equalizers of other boxes.
> 
> The sources are a Panasonic discman, an arcam CD player a squeezebox,
> and hopefully we will borrow a high end CD as well. I will obviously
> do it in pairs. I will have a helper switch manually. All units can be
> connected to my budget level integrated NAD 325 BEE and have a copy of
> the same media source.
> 
> My problem is how to neutralize differences in volume without
> investing in equipment I have no need for. I can think of four
> strategies
> 
> 1) For each test start with volume at 0 and have testers ask for
> volume to be adjusted to level they like.
> 
> 2) Have the helper randomly set volume each time
> 
> 3) (Maybe) use a PC to measure volume - not sure how to do this but I
> do have a cheap microphone and audacity on the PC which should show me
> the volume level - I don't know how accurate this is.
> 
> Advice appreciated.
> 
> Steve

Steve,

Arny is the "expert" on ABX.
I will defer to his comments on how to stage such a test.

But, you have to ask yourself what are you hoping to determine here?
You will not be able to hear differences that are being masked by
distortions 
inherent in your playback equipment. That includes distortions from your 
amplifier and your speakers.

Put it another way, if you put a virtually "blameless" source into the
test 
using a system with sufficient distortions of the sort that are detectable
by 
the ear - and absolute level is not the determinant - then it will sound
not 
much different than a unit that is reasonably "blameless" in all
probability.

It would be a better idea to merely match levels via some sort of simple
pink 
noise CD source and a cheap Radio Shack SPL meter or just a mic plugged
into the 
input of any device that has a level indicator - that includes a PC with a

soundcard and some software that shows level, or a tape machine with VU
meters - 
and simply set the mic in a fixed position and set the levels to be
identical 
using the pink noise, mark the volume control, and then let ur friend
switch for 
you, and set it up so that you can not see what he/she is doing.

That's NOT an ABX, but at least you won't know exactly what's going on...

For me personally, it doesn't seem to matter much since I'm not listening
for 
the things that it seems most people are listening for (simple level diffs
for 
example), and I do have the ability to level match nicely anyhow...

Bottom line is that if you find yourself wanting to listen to things for a

longer period of time, that is probably the gear/set-up to use. Simple as
that.

                _-_-bear