Behringer DCX2496 x-over, better than passive?

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EC8010 said:


Oh dear. Not good for credibility.


Well, rumour has it that they covered the electrolytics with red polypropylene sheet, the 12 mills variety of course. That should even convince you :D

Did you read the article? It IS entertaining, even if it doesn't conform to whatever your believe system is. Don't worry, you won't convert so easily! I think..;)

But I won't pull this off topic anymore. Sorry.

Jan Didden
 
janneman said:
(Later, Lipshitz realised that the noise level was slightly higher with the F1 inserted and that allowed him to score 100% by listening to that).

Jan Didden [/B]


Precisely, so when he realised what was different, he could hear it. When he did not know he couldn't. That is why blind tests are silly, because it can take a long time for you to fully realise what is different.

I wouldn’t mind betting that if this guy continued the blind test for 1 week, he would have heard that higher noise level without needing to measure it and then been able to score that 100%.
 
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Tenson said:
Why does it bother you that it takes one a long time to perceive the full reality of what is there? You can not analyse every aspect of sound in a split second.
[snip]

No, that's not what bothers me. What bothers me is that anyone making whatever changes he makes to his system always reports huge differences, and then when somebody does a serious test they fail to reliably identify the differences. That cannot be because the equipment is not transparant or whatever, because the reported - unsubstantiated - differences are always with a very wide range of different equipment as well. Maybe you need long time to appreciate differences in sound, but how can you then identifiy the differences just when you switch between units? And reviewers do that all the time, at least in non-controlled tests. Even reviewers fail the controlled tests. And this bothers me.

Tenson said:
[snip]I see no reason why I should not be able to tell the difference between three op-amps in series loading the DAC into IMD and a high quality transformer directly driven by and impedance matching the DAC directly to the power amps.

The opamp test was done, seven LM741's in series, in or out of circuit. No discernable difference under controlled conditions. I don't think they ALL had tin ears. Yes, that bothers me. I also clearly perceive differences in sound when I fire up my latest and greatest amp. But under controlled conditions, test run by someone else, me not knowing what is playing at any time, I make a lot of mistakes.

Jan Didden
 
Its not the op-amps so much as the fact they are a heavy load for the DAC causing IMD.

Again though.. it can take time to hear the difference.

I agree though that it is silly for reviews to rate equipment after only a few hours or a day or two listening to it and with a large gap between that and any other equipment they have done. But.... I don't read reviews, I demo it in my own house.
 
A/B tests are very hard for listeners if there are small differences between test units. What I find dificult is that if there is a big lag between A and B set up. Nature helped us that our brain adds what is not there so that is why we easily adopt to various sound sources. Kind of like retinal perception that allows us to see movie even do we look every 1/50 sec black screen. So I prefer immediate A/B test where you could switch back and forward instantly ( with the same level) while you remember previous sound. That is only how I could say that there is difference somewhere. Perception is another dificult factor if the blind test is not performed. We will always hear what we want to hear not what is really better. Without that there would be no advertising jobs, or ... journalism... lets don't go into politics. :cool:
 
comparative listening tests are an interesting thing. Many times what I thought was a "better sound" I found later to be the opposite. I wouldn't want to dispute either way if one DAC sounds better than the next.
What I would be really interested in knowing is whether any one has done listening tests on a loudspeaker using the digital crossover and then again using a passive crossover on the same loudspeaker. What conclusions were made then? Surely the differences would be (whether good or bad) significant enough to reach some opinions.

Dave.
 
In A/B tests with the DEQX versus the passive crossovers for the Salk speakers, the passives won. I beleive the passives used teflon capacitors. It's not exactly fair since the crossover slopes were very different, but for now I'm convinced since there is so little other subjective data. Not saying that the passives are "better" but merely more pleasing to the ears.
 
I did a test with DCX last weekend at local HiFi Shop also.

I have been tweaking/rebuilding my DCX2496 for two years now so as I had a 100% original unit that I helped my frind to buy. I was of course courious to compare them. I wanted to know if my unit is actually better....

The DCX-es were used as stereo DA and all settings zero. I also set the output levels from both units to within 0.1dB before I went there. During testing I could switch the SPDIF feed to one or another in few seconds and to switch the Accuphase amplifier between two inputs.

The general consensus by few guys who are very experienced in HiFi world was that my unit was defenetly better in every aspect of sound, clearer, more musical, more air. The original had more hiss in highs and "ssss" sounds. But the difference was not the total night and day kind.

Still I feel that here is the same symptom at play - meaning that if I listen to either one at home for long periods there is one BIG difference - my modded one can be listened for hours and hours whereas the original tires you out in one hour.

Ergo
 
Fazman,
I did that test on my speakers - sort of. I 've installed rocker switch on the speakers that allows me to go with or without pasive. Only problem is that I do not have pasive crossover between bass and mid, just between mid and high. So I couldn't pull DCX out of the chain. But what I find out was that in the first place I lost some of the volume because amp is going through the crossover.

I canno't say if there was difference in sound because DCX was all the time in the loop. Second variable is that by removing DCX that will introduce different D/A converter which will mess up the test. My feeling is that main difference between pasive and active is expressed while music has complex loud pasages played on higher volume. Only than, anything but best amps will show the difference. It is much easier for amp to drive single speaker.

In my active set up I have vacume tube for the mids and Aleph for the highs. That way I have the best of the both worlds. I wanted to hear difference between Aleph only driving speakers and my original dual set up - tubes and class A. I do prefer the later one vs. class A going through the pasive crossover, but that is more because of different type of amps and not because of different crosover. For me that is the main benefit of running active - all of the options and fine tuning available. Well designed speakers with pasive crossover with powerfull and high quality amp will sound equally good but than again you are talking about very big class A amp ...
 
And just to add this.
Before I decided on what speakers to build I made up my mind after I visited Mr. Linkwitz who happen to live just a few blocks from me. His opinion is very strong - nothing but active. When someone with his name and knowledge makes statement like that I certainly will take that as a definitive answer in question pasive vs. active crossover.
 
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fazman said:
comparative listening tests are an interesting thing. Many times what I thought was a "better sound" I found later to be the opposite. I wouldn't want to dispute either way if one DAC sounds better than the next.
What I would be really interested in knowing is whether any one has done listening tests on a loudspeaker using the digital crossover and then again using a passive crossover on the same loudspeaker. What conclusions were made then? Surely the differences would be (whether good or bad) significant enough to reach some opinions.

Dave.

I dfid sort of that a few weeks ago. I had in my room two totally different systems. A consisted of Martin Logan Sequel II speakers driven by a power amp of my own design, passive level controls and Rotel 950 CD player. B consisted of two way speakers of my own design with 4 * 50mm Jordans for mid/high and 2 * 150mm Jordans for low, each side, bi-amped with vintage, heavily modified Sony power amps and a Behringer (output modified) driven from the digital output of a Philiops CD950. I had two identical CD's in the players and was switching between systems using the CD remotes switching between play and pause. We (4 friends and me) spend about an hour tweaking the Behringer settings to try to bring B as close to A in absolute level, freq response etc, by ear. At the end we came very close but there was still a difference we heard.

Now for the interesting part: initially we more or less unconsiouslly used the big Martin Logans as references, but after a lot of switching we lost track of what was playing at any one time, and the preferences would switch back and forth. At one time one of us remarked, for instance, that he clearly preferred the stronger and more extended bass of the Martin Logans (they are physically imposing) to the Jordans, while in fact he was listening to the Jordans, and was embarrassed when I pointed that out. We had several of these occurences, and later laughed about them good-humoured, but the lesson was that even if there is a difference you tend to favour the more physically impressive system. Which is nothing new and extensively documented, and used by audio marketeers of course but it can be sobering to be confronted with it.

Jan Didden
 
Jan,
Really cool.
I sometimes listen to my set up in complete darkness so I can't see my own speakers. After listening to some Norah Jones last night I surprised myself to see that all that sound was coming from a 5" woofer and 1" tweeter.
The eyes will sometimes convince you of things your ears don't believe.
 
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