How to level match when comparing components?

I agree with Elizabeth and would take it one step further. Leave A in for a week or a month, then replace with B. Limit music during that time to that which you are intimately familiar with and best represents the range of your musical preferences with some emphasis of material that is demanding of the system. Otherwise A/B is useful on in knee-jerk evaluations of spot differences. How those differences actually play out in the long run enjoyment of your system are not fully understood in a quick A/B comparison, IMO, though some really blatant ones might be easy to eliminate some components from consideration entirely.

As far as matching levels, the original question, you can also get level meter apps for an iPhone and probably other similar devices that would be useful for such a simple task. I think the iPhone app that I have is by Studio Six Digital. One other note, it would be useful to have a recording of white noise (or pink noise) to actually use in association with the meter in order to match the level. It will be easier to use that then a recording of music that is probably changing rapidly. You can probably download something by doing a google search.

In addition to an SPL meter, you will need a pink noise signal. As Jax2 mentioned, using music to level match is nearly impossible.

I agree it takes time to fully evaluate a single component. For comparisons between two or more, direct A/B is necessary. You can't rely on memory, not even for seconds, because the differences are usually very slight. A selection of least 10 to 12 completely different styles of music and recording techniques is helpful. You might notice something different on one recording, yet nothing noticeable on another.

Then you have the real problem. Which do I *like* better, which *is* better?

Then you have the real problem. Which do I *like* better, which *is* better

I hope you are joking. If those two are different in your mind, then you do have a real problem. If you start trying to please someone else, or second guess some "absolute" or objective then you will never be happy with what you choose. The only thing that should be of concern is what sounds best to you, assuming you are going to be paying for it and living with it and enjoying your music through it. I guess if you are buying as a gift for say, Micheal Fremmer, then you should probably be concerned with what he thinks....otherwise it's up to you.

Listening in your home listening room is the best way, and as already suggested, at least a week of each player is best. All else is guessing.

I diagree with ojgalli as to the reasoning.
He is doing an immediate and sudden comparison. relying on attempting to remember a snippet of sound. My (and others) rely on long passages, and NOT so much on memory of the actual sound, but on how the sound made you feel. That feeling is easy to remember. And if it is repeated, the collected feelings of each product with the different music can give one a clear preference, which will last when actually owning the product.
One will remember some of the highlights of the sound, but the meat of the comparison is the emotional response.