Have you ever used a separate speaker selector unit to audition speakers? Would you?

@rrcpa I'm convinced. 

Since BOTH speakers go through the unit, a comparison would still be valid.

@aburn Well, that is one key point of contention, and you can see I've pointed to it a couple times in previous posts. You can also see different arguments for and against the usefulness of the proposal. Rather than rehash that material, I would just suggest reading the thread from the beginning.

For those of you with a myriad of arguments against using a GOOD speaker selector I say great, don't use one. I find it almost essential for making A/B comparisons. No, there is no free lunch so you have to do some work, like figuring out how to level match each and every pair of speakers.

I don't think I or anyone ever said that a speaker selector was the ONLY method that should be used. Every audio component requires a long-term test. But, audio memory being what it is (generally poor, despite what you may believe) this is the only way to hear glaring changes in their raw state. Is that valid? Sure, as one data point.

Are selector switches a weak link? Maybe, but I don't think that a GOOD selector box color the sound. At least I, my former customers and distributors never mentioned it if they did. But as @ aburnhamuu45 mentioned above if both speakers are wired through the same selector what's the difference? You are evaluating the delta between two equalized sources. Your long term test (without the selector) will provide your sound baseline evaluation.

@br3098 You succinctly captured what I thought was the argument for the selector as one point of comparison. I’m still curious to try it, though I see better why it might not help much.

One line of argument against it has to do with whether or not fast judgments are helpful. Some here argue they’re not. You say they can be (and this was my experience, too, but I’m questioning it).

But another line of argument against it has to do with the effect of the selector box on the speakers.

Just for the sake of argument, I can imagine a scenario where it doesn’t help or even hurts.

Consider a comparison between Speaker brand A and brand B using a selector.
In this example, imagine that Speaker A is greatly affected (obscured, masked, distorted) by the selector electronics but Speaker B is not. Voilà! What seems like a neutral test is actually making the comparison worse. The assumption was that the selector would affect each speaker the same amount, but that was a wrong assumption. (Imagine feeding the same amount of sugar to a diabetic and a non-diabetic. Should have the same effect, right? No, it shouldn’t because they start from different positions.)

It sounds like you have a lot of experience selling speakers over the years. Is the example I am offering here far-fetched? Happy to be corrected if so, but it seems plausible in theory.