"Proper" techniques for comparing two sets of speakers

ctviggen · « **on:** 13 Jul 2007, 05:04 pm »

I currently have two sets of speakers at my house. I was thinking of comparing them and wanted to "design" a plan to compare them. I'll definitely use a wide-band signal to adjust the output of each speaker to the same level. I may do this for multiple levels (say, 70, 75, 80, 85 dB with my Radio Shack meter) and then ensure that each song is played at whatever output/level I've selected.

It'll take me about 10 minutes to switch the speaker cables, as I have a Bolder Cable product that I use to couple one set of binding posts to another. I may also try to move one set of speakers out of the room while testing the other set. Add another 10 minutes for that. So, that could be 20 minutes between listening sessions. How does one remember what a song sounded like with this type of time delay? Notes? If so, what type of characteristics of the songs should I use? Any other techniques for this type of comparison?

miklorsmith · « **Reply #1 on:** 13 Jul 2007, 05:09 pm »

I'd listen to each for a period of days then switch. Speakers should be fairly easy to compare. I've never had good experiences trying to quickly A/B stuff. Differences can be found in so many places that it's hard to distill down to A, B, C areas of interest.

What are the speakers?

bpape · « **Reply #2 on:** 13 Jul 2007, 05:16 pm »

Not to mention having another set of speakers in the room will color the sound. The pressue in the room makes them all vibrate and impart a bit of their own sound into the mix. That's why I always hated having to have a showroom that had multiple speakers in it. The same speaker will sound a lot different with several other sets in the room than if it's the only set.

Bryan

macrojack · « **Reply #3 on:** 13 Jul 2007, 05:18 pm »

If the sound is so close you need to design a program of comparison to find salient differences, you should forget sound and choose on some other basis because you won't miss the other pair once they are gone.
This isn't exactly Sophie's Choice after all.

SET Man · « **Reply #4 on:** 13 Jul 2007, 05:33 pm »

Hey!

Well, you could do it this way....

1. Invite couple of your audiophile friends over. Make sure a few of them show up with somthing like this...

2. Have 6 of these before any serious listening...

3. Than put on a blindfold... make sure you have a 7th bottle of beer in your hand, than sit in the sweet spot and listen...

4. Than ask your still sober audiophile friends if there any left to do speaker switching for you...

5. Repeat step 1 through 4 if you are still not sure.

Anyway, just kidding guys!

Take care,
Buddy

PS
Pictures gathered from NY Raves from Levi's gallery.

brj · « **Reply #5 on:** 13 Jul 2007, 07:56 pm »

Quote from: bpape

Not to mention having another set of speakers in the room will color the sound. The pressue in the room makes them all vibrate and impart a bit of their own sound into the mix.

When I first heard the prototype GR Research LS6s, a pair of Dunlavy SCIVs were still in the room. It was amazing how much sympathetic movement occurred in the Dunlavy woofers when the LS6s were playing. Basically, they acted as some really large passive radiators not tuned to the connected speakers or the room. You could reduce the movement a bit by altering the position and orientation of the disconnected speakers, but it was still very obvious. We eventually had to move them out of the room to avoid the problem.

Granted, I'm talking about two pairs of speakers with lots of driver area and ability to energize a room, but I have to imagine that you'd see the same issue to some extent even with small pairs of bookshelf speakers.

To address the rest of the original question, I think you are going to have to pay attention to plenty of issues even if you have a nice large, well-treated room and great components. Synergy is definitely one potential issue. One speaker may have different impedance characteristics or be more current hungry than another and thus be better suited to a different type of amp. (Speaker cables with a different balance of RLC parameters could likewise make a difference for the same reason.) One speaker may have more extension at either end of the frequency spectrum than another, thus exposing more differences in the upstream component chain that have nothing to do with the speaker itself. Some speakers don't "come alive" until they hit a certain dB level. (I've heard various explanations for this before, but don't remember the details off-hand.) Suffice it to say, comparing speakers fairly and accurately may not be easy even if the listener has the ability to filter out their own personal, subjective preferences and eliminate the more obvious variables.

markC · « **Reply #6 on:** 13 Jul 2007, 09:32 pm »

Buddy,
That was freakin' hilarious-I laughed my ass off! Thanks.

Daygloworange · « **Reply #7 on:** 13 Jul 2007, 10:07 pm »

Funnily enough, recently I've been doing A/B comparison of 2 very similar speakers. GR Research OB 5's and OB 7's. This pair here have the exact same tweeter network, the mid network in the OB 5's and OB 7's are normally identical, with only a difference in the woofer network due to the different configuration of that section. However, these OB 7's have an updated mid network as a result of testing in this new totally open baffle configuration that differs from the first models which had the open baffle top portion shrouded with a back and a top, with open sides. Both models will sport this new network, however, these OB 5's are awaiting the parts on order for them to be converted.

This is the sequence that I have found to be the best for listening comparisons. I set them up from left to right in this sequence, OB 5- OB 7 on the left side of the room, then OB 5- OB 7 on the right side of the room as well. That way you don't have one pair sitting inside another pair ( and therefore closer together than the other pair ). You also have the same first reflection point ratio to the side walls, albeit asymmetrical to the left/right speakers themselves. You simply shift your center position slightly going from one pair of speakers to the other.

I also leave a decent space in between the speakers so that you don't mess the baffle step of the speakers. I don't use a sub initially, but add it towards the end of the session, to see how the mains to sub integration differs in room.

The way I find best is to split music into categories, and listen for different things. For example, I will listen to one track specifically because of the drum track. I'm listening for detail in transients, timbre, impact,dynamics, depth, spatial location, and FR response and distortion.

I'll then pick tracks that feature instruments, and vocals that I know well, and go through the same sequence for both speakers. This is where I've been able to here very clearly the differences between 2 speakers.

I highly recommend devising as rapid fire a method to do the change overs as possible. Having the dormant speakers in another room while you listen to the active pair is not a good idea IMO. I recommend the set up I mentioned before. If you can get a buddy to do the wiring change overs for you while you sit in the same spot, that is really helpful, and I would highly recommend that. Also have a remote that can cue, pause, etc ..is very important. (If your CDP has an A/B loop feature, that's a huge bonus).

I listen to short segments of sequences, looped a number of times, them pause, and change over. I can do this half a dozen times or more on every featured instrument.

I also sit back and listen to complete tracks and employ a more casual approach as well.

As far as the dormant speaker acting as a passive radiator, yes, the drivers are moving sympathetically. So will other things in your room, and act as passive radiators as well, including the walls. You can't possibly eliminate everything. I thought about that as well, so I would throw a heavy shipping blanket over the dormant speaker to minimize the sympathetically moving drivers affecting things. I did some A/B 'ing of the effects, and the effect was not really noticeable ( I'm in a large space, with no nasty first reflection points, and a really high [ 17'] ceiling, so YMMV).

The other thing I found was that you are best to listen with your eyes closed. With your eyes open, they are scanning as you are listening, and therefore, multi-tasking. Your perception of sounds is much better when your eyes are closed.

In the test I just finished doing, I was able to hear differences very, very clearly between these 2 very similar speakers. I probably spent between 10 and 12 hours total. And plan to do the same once I update the mid network in the OB 5's.

Cheers

Housteau · « **Reply #8 on:** 13 Jul 2007, 10:14 pm »

Quote from: macrojack on 13 Jul 2007, 05:18 pm

If the sound is so close you need to design a program of comparison to find salient differences, you should forget sound and choose on some other basis because you won't miss the other pair once they are gone.
This isn't exactly Sophie's Choice after all.

Blasphemy!! Burn the heretic.

zybar · « **Reply #9 on:** 13 Jul 2007, 11:47 pm »

Quote from: macrojack on 13 Jul 2007, 05:18 pm

If the sound is so close you need to design a program of comparison to find salient differences, you should forget sound and choose on some other basis because you won't miss the other pair once they are gone.
This isn't exactly Sophie's Choice after all.

I can safely say the two pairs of speakers don't sound anything alike and aren't going to be similar in their presentations...

If they aren't compared on their sonic merits, then the comparison becomes very one sided in this case. aa

Have fun Bob.

George

NealH · « **Reply #10 on:** 14 Jul 2007, 01:41 am »

You should play a cut twice on one speaker then, change and play the same cut once on the second set. Following a short delay, play that cut once again on set #2 then switch and play it once on set #1. Pick another cut and repeat the cycle except this time start on speaker set #2.

Anyway, this was described in detail in one of the Audio Critic issues a number of years ago and, I think I have it right to the best of my memory. I probably have the copy but, it is too much trouble to go dig it out now. This approach to A/B'ing was previously described by some famous Japanese cartridge engineer who's name escapes me at this moment. The Audio Critic was just reprinting the original article.

macrojack · « **Reply #11 on:** 14 Jul 2007, 01:56 am »

Pick a pair. Focus on what you are hearing and enjoy it. Disregard any thoughts of what you are missing and be happy. If it is really all about the music, my suggestion will work quite well. If it is about some other matter, then you may as well be comparing anvils.

James Romeyn · « **Reply #12 on:** 14 Jul 2007, 02:03 am »

Quote from: macrojack on 14 Jul 2007, 01:56 am

Pick a pair. Focus on what you are hearing and enjoy it. Disregard any thoughts of what you are missing and be happy. If it is really all about the music, my suggestion will work quite well. If it is about some other matter, then you may as well be comparing anvils.

August '07 Stereophile "As We See It" editorial by Wes Phillips (pg.3) is an excellent counterpoint.

Carl V · « **Reply #13 on:** 14 Jul 2007, 02:06 am »

good luck in your A/B testing methodology.

Some obvious salient points:
*auditory memory is suspect with delays of more than a minute or so. There have been many auditory/acoustic journal; articles dealing with this.
* level matching is critical.
* room positioning is a sticking point.
* sighted listening tests will skew your perceptions....we're only human.

If you have identical amps you can hook both sets of speakers up to their own amps & leave them plugged in, the current will minimize cone movement of the dormant speaker. You will need a way to balance the gain of each amp though.

I have done quite a few of these comapare & contrast sessions. I have found that using multichannel amps, which have individual gain controls helps. Parasound & Cinenova 6 channel amps have been my amps. Close your eyes & have someone switch back & forth as fast or as slowly as you need & differences will manifest themselves. Close your eyes....& don't be allowed to know speaker postions.

lastly consider a test I observed at a S-California Speaker (Revel) company and oddly enough read about from Dynaudio.

Listen to MONO recordings on a single speaker. Switch left to right. (balance control) you stillneed to have gain/sensitivity matched. You have now taken off the table sound stage, imaging etc., you now must concentrate on TONE & PITCH. Dynamics. It's harder & easier to nail down the sonic character of the speaker. Harder because MONO is a more than likely a new experience for you. Easier because there is no place to hide.

Good luck & have fun.

The Sophie's choice comment was classic.

James Romeyn · « **Reply #14 on:** 14 Jul 2007, 02:38 am »

Quote from: Carl V on 14 Jul 2007, 02:06 am

...Some obvious salient points:
*auditory memory is suspect with delays of more than a minute or so. There have been many auditory/acoustic journal; articles dealing with this.
...

Several personal experiences contradict the above quote.

I am familiar w/ the sound of a friend's LEDE soundroom & have visited continuously over the years. At least three maybe twice that many times I've auditioned, left for at least a few weeks, then returned to hear the same speakers. In no way was anything revealed about the state of the system whether identical or changes had occurred. Changes as small as a DAC swap were apparent. Any time a change was predicted a change in fact had occurred. Not sure if any time a change had occured that was not noticed, but often the speakers were different (speakers always were visible but component changes were never visibly apparent)

Maybe labeling it a "lucky guess" is the only way someone who chose to believe the top quote could reconcile the two posts.

aerius · « **Reply #15 on:** 14 Jul 2007, 02:44 am »

In my case, I found what works best is to keep the listening sessions relatively short, about a couple hours at most at a time. Longer than that and my concentration starts going south along with my ability to tell things apart. The other thing I've found is the more switching I do, the more confused I get. If I switch back & forth 10 times in a single song (using an extreme example) I won't even know what I'm listening for and very quickly reach the "this is stupid, F-- it!" stage. Play a couple songs, switch, play them again, then replay passages as needed to zero in on the specifics. Then play more songs and repeat.

macrojack · « **Reply #16 on:** 14 Jul 2007, 02:52 am »

Much ado about nothing.

Do you agonize over shirts or washing machines or toast in this way? Hell, no. You just find something you like and run with it. Why, when it comes to audio, do we drive ourselves bats and back over the chance that some other product may have been available at the time that I chose mine and I may have liked it better. So friggin what? The big difference is those stupid magazines. They are the people who anal-ize everything and make it so much more complicated than it needs to be.

Just as beauty is said to be in the eye of the beholder -- so too is it in the ear. How you listen - what's in your heart and on your mind when the record spins - will affect your experience much more than any external equipment change ever can.

Have you tried the Teleportation Tweak on both pairs yet?

lonewolfny42 · « **Reply #17 on:** 14 Jul 2007, 04:12 am »

Quote from: zybar on 13 Jul 2007, 11:47 pm

Quote from: macrojack on 13 Jul 2007, 05:18 pm
If the sound is so close you need to design a program of comparison to find salient differences, you should forget sound and choose on some other basis because you won't miss the other pair once they are gone.
This isn't exactly Sophie's Choice after all.

I can safely say the two pairs of speakers don't sound anything alike and aren't going to be similar in their presentations...

If they aren't compared on their sonic merits, then the comparison becomes very one sided in this case. aa

Have fun Bob.

George

Sounds like the same comparison we did at your house George awhile back.....

zybar · « **Reply #18 on:** 14 Jul 2007, 11:09 am »

Quote from: lonewolfny42 on 14 Jul 2007, 04:12 am

Sounds like the same comparison we did at your house George awhile back.....

Yup.

We all know how that turned out...

George

macrojack · « **Reply #19 on:** 14 Jul 2007, 12:50 pm »

The speakers still have not been identified and the mystery deepens as Tri-State insider jokes emerge.

How did it turn out?

Maybe the best thing for Mr. Viggen to do would be ditch both those inferior speakers and buy my Zu Definitions. This would relieve the burden of comparison by introducing a third element so clearly superior as to make comparisons laughable. Furthermore he would enjoy that warm feeling that always arises in the soul upon having aided a fellow AC member in his time of need.

Consider my unwieldy predicament for just one damn moment if you don't mind too much. Here I sit with an incredible set of world class speakers cluttering my life and impeding my advancement into ownership of their marginally better replacement model just because you guys are selfishly holding onto your own money rather than forwarding it to me. Have I not made myself clear? This is important.

Apparently you all think that just because you are happy with the speakers you have that you bear no responsibility to those of us who are less content. Well, that is simply not the case. Your fellow AC members are all you have in this cold world. Where's the solidarity? Where's the compassion? Doesn't anybody want to bi-amp?