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In Reply to: Re: I'll get a copy of that review... posted by klausDK on March 27, 2007 at 08:15:41:
Well, the same. Amplitude response on axis (flat ±1.5 dB), off-axis (nasties start at about 16 kHz with one narrow-band irregularity at about 2.8 kHz), step-response (almost ideal), waterfall plot (almost empty). Trick is, they use digital x-over and digital equalization.
Re: Bruel & Kjaer curve
The curve that you have shown us some time ago and which you apparently like so much is, according to their AES paper, for "recordings which are made as a combination of far-field and near-field information". For recordings under far-field conditions the curve should be "absolutely flat", since then the recording contains a mixture of direct and reflected sound.
Sure, the Pioneer measure much better than the average high-end stuff. I would like to see the vertical off-axis response.
The review sample showed a rather important resonance in the 300-500 Hz area. The measured amplitude response on-axis is very similar to the one in Stereophile. Overall ranking was 91 points, exactly as much as for the Wilson Maxx two years later (Pioneer was reviewed in Dec. 2005), which costs 6 times more!!!
The reviewer apparently likes the Pioneer (sovereign imaging, bass with no signs of "grease", harmonically rich and with body, rocksolid, you don't hear that every day, dynamically restrained, even hot CDs sound acceptable, this speaker doesn't jump on you, the sphinx of rock smiles).
A reviewer collegue apparently did not like the Pioneer. However, this other reviewer was just busy reviewing a Focal with Be-tweeter, which, in reviewers' terms, was a very differen beast altogether, coffee with sugar vs coffee black, so to speak.
So it was just the opinions of two reviewers. The (cheaper) Focal got 96 points, btw.
I wonder about the resonance at 300-500 Hz.
Cumulative spectral-decay plots shall only be used with care and will require a big or anechoic measurement room if you want to make any useful conclusions for frequencies as low as 300 Hz. Considering this supposed resonance is right smack on top of the crossover frequency at 350 HZ I wonder if it isn’t a phase abnormality from the chosen passive crossover. If this is the case then it will obviously be much less intruding than if it had been a proper resonance. Looking at the construction materials etc. I will have to say that the only true type of resonance I can imagine at all will have to be standing waves!
Still it would be fun to see how it would measure, and sound (!) if the crossover between bass and mid was handled by a very high order digital crossover with some phase compensation.
I feel cumulative spectral-decay plots at low frequencies should be used much more to determine speaker room interface rather than just to look at the speakers in isolation.
In a way you could say that is exactly what Audio has done by not filtering the response like Stereophile do. But what I really would like to see is a plot running for 20 milliseconds rather than 4 milliseconds.
Before typing this reply I have had a look at Kef’s homepage because their reference series share the same construction philosophy as the Pioneer. And hurray reviews of the new Reference series is by now being presented there. They have a a non functioning link to a “Stereo” test of the Kef R 205.2 and this test of the R203.2
Its on axis frequency response is actually better than the Pioneer and within its frequency range as perfect as we are ever likely to see from a passive box. And I would not be surprised if its dispersion control wasn’t basically identical to the Pioneers.
Then again it gets a good review so it doesn’t inflict with your statement/view!
On Kef’s homepage they have pictures of the crossover boards from the Reference series and they look almost like parts of an amplifier, utterly filled with components 40+
Some believers in the “less is more school” will argue that this is newer going to sound good. I say one has to use the amount of components which is needed, no more no less.
B&W and Kef was once more or parallel running companies which seem to follow the same engineering path. Now their ways seems to divide, and I like more what I see from Kef rather than B&W.
Best wishes from Sunny Copenhagen.
I don't know how and where Audio is doing their measurements so I can't comment. However, apparently that resonance is not present in the review sample of Stereophile.
FYI, KEF was involved in the Archimedes project in Denmark. Some papers have been published in JASA by S. Bech (timbral and spatial aspects of sound reproduced in small rooms).
Thank you so much for all your effort KlausR.
As I have the flue I will try to reflect and respond tomorrow, if I my health permits.
For now I will suggest to others. Give KlausR a challenge: If you do not believe like he does (and I do to some degree) that a good loudspeakers can be identified by its measurements. Then show him a good measuring speaker, with a bad sound.
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