The A/B process...

[Brandon Burke]

Let me get this straight...

When you guys "A/B" different CDs does this mean that you have two entirely seperate yet identical CD players? Seems to me that that would be the only way to get an accurate representation. If not, then what exactly are you comparing? Sounds like two different mastering jobs through two different CD players to me.

Just asking...

[Dmitry]

What do you mean by A/B'ing different cds?

A/B'ing the same music on rvg vs. jrvg vs. tocj vs. collector's choice, etc?

[wolff]

I'm not sure I get your question. Why would you need two identical set-ups to A/B a CD? I don't do much A/Bing, but when I do it's through the same component.

I still do the occassional LP pressing comparisons and I just play them one at a time on my turntable.

I've compared a few LP burns to the commercial CD counterpart and I play them in my CD player over and over.

When I A/B components I like to leave one of them in my system for 2 or 3 weeks and then switch to the other one and leave it in for a week or two. Then make my decision.

[Claude]

You are right Brandon, but generally the differences in CD remasterings (RVG vs TOCJ) are so much higher than the sonic difference between CD players that the latter is hardly relevant, as long as both players are of a good quality.

An option is to do two A/B tests and switch the discs between the players for each test.

More important is the possibility to compensate volume difference between players and discs, but most setups don't have that. It is very difficult to A/B two discs if the volume has to be adapted manually at every switch.

Edited May 19, 2004 by Claude

[robviti]

my friend kevin and i have conducted many a/b comparisons (and quite a few a/b/c ones too!). most often we don't have the luxury of separate components, and frankly i'm not sure why that kind of a setup would be an advantage. more important, i think, is to have more than one person involved in the testing. i'll put the cd on and have kevin listen to it. then i'll put on the other cd and have him compare it to the first. we usually compare mutliple tracks, and sometimes we go back and forth. it ry my best to confuse him at times, so that only real differences in the sound will be readily apparent. also, i try to adjust for volume differences before the music is played. if this whole process isn't followed, then: a) i'd know which cd is being put in the player because i put it in there myself, or b) i'd know which one it is because i hear a distinct change in volume. Either way, confounding factors like anticipation and bias will play a role in my perceptions of the differences I think I hear. This whole thing might sound unnecessary or too involved for some (hey, I'm a psychologist that does testing for a living!). But I assure you, it can be fun to do and the results will amaze you sometimes.

Edited May 19, 2004 by jazzshrink

[Brandon Burke]

Interesting responses. My assumption was that a *true* A/B whould be pressing [play] on two different playback devices at the same time and then switching back and forth with your reciever. I guess I have a different idea. Anyways, thanks for the replies. I have always been curious about how exactly you guys compare fidelity between diffrent recordings. Apparently, there is a greater difference between TOCJs and RVGs than I thought. I don't know. I buy LPs and US reissues.

I still say that from an audiophile prespective--which is the point here, right?--that using different CD players corrupts the results.

Brandon

[Dmitry]

Most of the time the differences between cds are such that it really matters little what 2 cd players you use to compare.

I still don't understand the reasoning behind having 2 players to compare 2 cds. 1 player-2 cds seems sufficient to decide which sounds better to my ears.

[Brandon Burke]

I still don't understand the reasoning behind having 2 players to compare 2 cds. 1 player-2 cds seems sufficient to decide which sounds better to my ears.

I think you're misunderstanding me. All I'm saying is that a true test would need to be conducted on an identical CD player (be it the same player or another just like it). That's all....

[Brandon Burke]

Also, I still say that the time it takes to switch CDs on a multi-disc player or take one out to replace it with another is enough time to forget what you were listening to before. I mean, in theory, that's the origin of the "A/B" term; that you switch back and forth between concurrent streams funneled through the same reciever.

[Dmitry]

I still don't understand the reasoning behind having 2 players to compare 2 cds. 1 player-2 cds seems sufficient to decide which sounds better to my ears.

I think you're misunderstanding me. All I'm saying is that a true test would need to be conducted on an identical CD player (be it the same player or another just like it). That's all....

I dunno...my aural memory is good enough to lock in how one cd sounds, at least long enough for me to run to the cd player and put another one in.

But theoretically you're right, of course.

[Daniel A]

Brandon, my concept of an A/B test is pretty much what you're describing too. For just the reason that I've never had access to two identical CD players when doing such a test, I've never been able to compare two CD masterings in that extensive way, but I've been practising it when comparing different media types like MP3s/CDs/LPs etc. It may of course be just my prejudiced idea of an A/B test, but I imagine that subtile differences would be easier to spot when you're given the option of simultaneously switching back and forth between the two sources during playback.

Edit: I also agree with Claude that setting the volume equally between the two sources is rather more important.

Edited May 20, 2004 by Daniel A

[DrJ]

Here's my philosophy: if the difference in your A/B test is so subtle that a few seconds pause to switch discs makes you forget all about it, then it's hardly worth fussing over. I agree with Dmitry that if you're an avid listener, you've usually got a highly developed "aural memory" and you're gonna hear and remember important differences regardless of the pause, while the trivial differences will fall away which is probably a good thing (could save you $1000s!).

I also don't think manually adjusting the volume to comparable levels for A/B testing is that difficult. Again, if a slight difference in loudness between your A and B disc makes THAT much of a difference in sound quality to your ears, my assertion is that it's not just the volume difference at play but rather a superior remastering.

Thus I do A/B's with the same CD player - whatever my current "best" player is - because I want to know what different remasterings are going to sound like through that player.

Unless you go and buy two of the same player, which seems a complete waste in most instances, I don't see the point of using two different players UNLESS you're trying to decide about buying one over the other (some audio places will loan them out for home testing for example), a different kind of A/B test where you use a single CD obviously.

Another reason to employ a single CD player for A/B's - what Claude says about high end CD players being so similar sounding that it's probably a non-issue, I'm not sure I agree with at all. Based on my recent listening research in assembling a listening room, there are HUGE, readily audible differences between very high end players, e.g. a Mark Levinson vs a Meridian). And again, I'm not a "subtle distinction" kind of guy, I'm only impressed/bothered if I can almost immediately hear differences.

At any rate, FOR SURE in the low to mid-range CD player field, I hear HUGE differences among players - not necessarily a better/worse thing, but differences nonetheless. For example, my Pioneer Elite DV45-A has a more detailed, bright sound and seems more responsive than my Onkyo 6-disc changer (which sounds darker and more sluggish and reveals less detail). Some of this relates to the DACs in the unit, some to the transport, some to other circuitry (particularly in "all in one" players), and there are probably many other factors too. Beyond sound coloration (darker versus brighter), as I allude to above, a big difference you can pick up right away concerns responsiveness - some players just sound "sluggish" or slow, like everyone is dragging and the tempos are just a little "off," while others sound right on-the-mark. This effect is a little more subtle, certainly not at the level of playback speed problems that grossly effect pitch, but definitely audible.

Edited May 20, 2004 by DrJ

[jazzbo]

I'm with Dr. J on this one, all the way.

[bertrand]

Dr. J is on the money. I hardly ever upgrade, but when I do, it's because the original source sounds like such crap that *any* remastering would be an improvement. There's no need to sit down and do and A/B comparison. I put the new version in, and if the 'problem' is corrected, I'll know immediately.

I also agree that the sound changes between CD players even with the same speakers and receivers, regardless of what the schmo at Circuit City says.

I have one CD I would love to upgrade - the 1993 US version of Wynton Kelly's Kelly Great. The one I have is totally fucked up. Unfortunately, the only remastering is the soon to disappear Mosaic Kelly box, and I just can't justify buying this one which contains a lot of material I already have, when I have 5 Mosaics on my wish list that I still haven't gotten around to buying.

Bertrand.

Edited May 20, 2004 by bertrand

[jazzbo]

There's always the Blue Moon and a Japanese edition or two isn't there Bertrand? The Mosaic has better mastering (and is remixed as well) but the Blue Moon and Japanese VeeJay versions of the material sound better than the US "VeeJay Partnership" cds did!

[Morganized]

You are right Brandon, but generally the differences in CD remasterings (RVG vs TOCJ) are so much higher than the sonic difference between CD players that the latter is hardly relevant, as long as both players are of a good quality.

An option is to do two A/B tests and switch the discs between the players for each test.

More important is the possibility to compensate volume difference between players and discs, but most setups don't have that. It is very difficult to A/B two discs if the volume has to be adapted manually at every switch.

Brandon, you are correct in equipment choice and Claude is right on the money on this one as well. True A/B is very difficult to do correctly, especially when the volume levels are different.

[bertrand]

Jazzbo,

Actually, someone told me the Blue Moon sounded almost as bad as the Vee Jay partnership one. There's some wierd distortion in the drums that sounds totally unnatural.

In fact, for all I know, this distortion may be in the tape and therefore still be present on the Mosaic. Never thought of asking here...

The Shorter/Morgan Mosaic sounds great (except Wayning Moments), so if the tape is OK, I think the Mosaic will be OK.

Anyway, I digress...

Bertrand.

[SGUD missile]

Most all of the A/B- ing I 've dealt with has been in the prerelease stage in a control room: either in checking some feature like EQ or compression in the mastering stage, or in checking individual mix elemets earlier on.

both of these procedures are of course from the same PB source and at the identical volume level and listening environment ..it's a matter of flipping a with/without switch during playback.

a lot of what's been seemingly discussed here has been different Re-MIX versions as well as different re- MASTER versions as well.

I do agree that the PB levels of the comparison CDs is crucial ..I dont think the brand of CD players are ( given that the same amp and speakers are employed in the comparison.. and that the playback curve is set flat)

after all ..it's all 1s and 0s

Edited May 20, 2004 by SGUD missile

[jazzbo]

Well, I have had the US disc, the Blue Moon and the Mosaic. Each sounded better than the other. Not sure that I remember a specific distortion on the drums, but it may have been there on the US and the Blue Moon and still be on the Mosaic. . . I may have to visit that Mosaic soon and that session. . . .