Question about A-B testing Speakers

[derblott]

I would love to be able to test 2 pairs of speakers side-by-side on the same amp with the flick of a switch. Is there some kind of in-line device that would take the speaker wire output from the amp and split it into 2 pairs of speakers and allow me to switch back and forth on the fly? Or are there any amps with this feature built in? Interested mainly in tube gear, so I may have to take this question to the tube forum for specific gear (if any).

Thanks.

 

[Llama50]

Niles Audio has a speaker select switch that usually sells for around $40 on that auction site. I found a selection switch made by radio shack for 3 pair of speakers at GW for $3.00.
Most recievers and integrated amps have A/B speaker select switches.

 

[Nat]

Its tougher with tubes, since its possible that different impedance speakers will sound different because they are not hooked up to the correct tap on the amp. I don't think that the difference would neccessarily be very significant -- less efficient power transfer and perhaps different damping -- but I would also listen to the speakers hooked up to the correct tap as a check on the results with the switcher.

 

[Pyrrho]

One thing you will need to deal with is the fact that human hearing is nonlinear; differences in volume are subjectively perceived as being qualitatively different, with the louder one sounding more "full". When one turns down the volume on something, the bass subjectively appears to diminish faster than the midrange (the subjective qualitative difference resulting from differences in volumes is sometimes dealt with by modifying the frequency response; that is the purpose of "loudness compensation" circuits, which are often engaged with a switch marked "Loudness"). So, if one compares two things that are different in volume, the bass will subjectively appear to be better (or greater) in the louder one (all else being equal). It should not be necessary to add, that, of course, one can hear more detail with a slightly louder sound as well, so it isn't just the bass that appears to be improved by a very slight increase in volume. So your switchbox needs to have independent volume compensation for the different speakers so that you can level match them to each other. Otherwise, you will tend to end up preferring speakers that are slightly more efficient, even if they are no better, or possibly even if they are slightly worse.

 

[derblott]

Thanks for the info, and that's an interesting point about the efficiency. But if I was testing speakers of equal or similar efficiency I would be probably be ok? The speakers I want to test are the best buy insignias vs the original large advents. The insignias are 90db, and the advents are guessed to be 89-90 also. Guess I'll head to radioshack!

 

[nathanso]

I've done a good bit of a/b testing and can concur that you want a device that lets you adjust levels, like the Niles SVL-2.

 

[uofmtiger]

I would take an SPL meter and test them to see what volume level I need to have set on the amp for each speaker to make them equal before starting. Then I take the amp input to something without a signal after testing speaker A, then I adjust the volume and go to speaker B...

 

[Paul C]

One problem with A/B testing speakers, the louder one is usually chosen as "better", so yes, match volume as well as you can.

Also, if the first has hyped bass or treble, and the other is flat, the second may be perceived as lacking or dull.

So, A/B test, but also do some extended listening on a variety of music. I prefer to NOT us any sort of sythesized music for testing because you don't know what those tones should sound like to begin with.

Live music, real drums, "acoustic" instruments, are a better source. You know what real instruments should should like. Live orchestra recorded in a concert hall, a jazz or folk group recorded live, etc, are good choices.

 

[Pyrrho]

Thanks for the info, and that's an interesting point about the efficiency. But if I was testing speakers of equal or similar efficiency I would be probably be ok? The speakers I want to test are the best buy insignias vs the original large advents. The insignias are 90db, and the advents are guessed to be 89-90 also. Guess I'll head to radioshack!

No, you would definitely not be okay comparing a speaker of 89 dB efficiency with one of 90 dB efficiency without level matching. With small differences in volume, typically one does not notice a difference in volume at all, and only perceives it as having more bass, being clearer, etc. And even if they were rated the same, that would not mean they were the same, as these numbers are rounded off (no one says, 'it produces 89.3257 dB @ 1 watt @ 1 meter'), and may not have been measured exactly in the same way anyway.

Another problem to be concerned about is the influence of speaker placement; you cannot put them both in the same spot at the same time, so you will want to listen to them one way, and then switch them and listen some more, as one position may be better than the other.

 

[luvvinvinyl]

Maybe I'm the odd one, here, but I take a slightly different tack, for comparing pieces. Put the new one in, and listen for a week or two, to music with which I am very familiar. Then switch back to the old one, and go over the same music. I find it easier to compare the old one, returning, that to appreciate the new one, when it first arrives. I have to live with it for a while.

BTW, my decisisions have been just about split, between old and new pieces, for speakers, interconnects, speaker cables...

 

[RichPA]

I generally agree with Ernie, at least in terms of choosing what I want to live with. A/B style testing can be fun, though - but level differences and other issues raised here are reasons not to take most of it too seriously, if you haven't done the work to really make conditions equivalent.

 

[tcdriver]

So, A/B test, but also do some extended listening on a variety of music. I prefer to NOT us any sort of sythesized music for testing because you don't know what those tones should sound like to begin with.

Live music, real drums, "acoustic" instruments, are a better source. You know what real instruments should should like. Live orchestra recorded in a concert hall, a jazz or folk group recorded live, etc, are good choices.

I agree with these comments. It is also important to listen to music and recordings that you know very well.