I agree with this observation. Are the famous "spin" tests also done in this room with those other speakers in such close proximity to the speaker being tested?
Peter, I explained all of this repeatedly in the other thread. How can you turn around and ask this kind of question, seemingly ignoring everything I wrote???? This is the picture I posted for where the measurements are performed:
It is an anechoic chamber. How on earth do you measure a loudspeaker for radiation at one specific angle in a real room where reflections are bouncing all over the place?
Note that magazine reviewers are not measuring this. They don't have access to anechoic chamber so they approximate by keeping the microphone close to the loudspeaker. That technique has limitations such as lack of integration of drivers at too close or a distance, or inclusion of too many reflections at farther back. So while informative, and decent approximation, they are not the same thing.
It does not look like other anechoic chambers that I have seen photos of.
We don't perform listening tests in anechoic chambers. We perform them in well, a room. Harman has multiple such rooms. I have shown you a picture of one with a speaker shuffler that I sat in. There are others at Harman. Here is one where the loudspeaker is rotated in place. That room is built to an ITU reference standard for acoustics testing and one is supposed to be a model of "domestic listening room." Here is a picture of it I took while Dr. Olive was running the speaker training test on us:
The turntable for the loudspeakers unfortunately is behind the video projection screen. But essentially three loudspeakers are mounted to it and rotated. This is used for in-wall and car audio speakers. This room was also used for Room EQ blind testing. All the results in this room mirror the one used in the other room. There is a whole conference paper on design of this room.
Here is one where they can shuffle stereo speakers and in a much larger room:
And the other end of it:
As with everything else Harman does, there is extensive research paper and testing published for this room. Here is the end of that paper:
"4.0 CONCLUSIONS
In summary, we have described a new facility designed to test multichannel components
efficiently and as bias-free as possible. The facility includes acoustically transparent
listening screens that hide the identities of all multichannel loudspeakers and equipment
within the audio path. Particular attention has been taken to address the two of the most
problematic variables in listening tests: the listening room and the position(s) of the
loudspeaker. Through the use of a computer automated speaker shuffler, we have greatly
reduced the amount of time and effort required to set up and test multiple comparisons
between loudspeakers by reducing the factor position to a one-dimension or level
variable. Typical loudspeaker evaluations should be reduced in length by a factor of 24:1.
The listening room itself is capable of testing up to three different 5.1 or 7.1 channel
systems and accommodate 1-6 listeners at a time. The measurements we have shown in
this paper indicate its performance in its current form meets the very highest standards set
out by the ITU and EBU recommendations, in terms of volume, geometry, reverberation
time, and the control of early reflections. The acoustics of the room can be easily altered
from hemi-anechoic to more typical domestic room conditions by adding reflective
panels to the room’s boundaries.
Finally, the experimental design, set up and control are computer-automated so that
experiments can be easily repeated, and are less prone to human error. The more time consuming
and mundane tasks such as collection and analysis of data have also been
computer-automated, so that experiment report writing becomes a simple cut-and-paste
operation."
Really guys. You have to resist the urge to keep thinking this is a bunch of corrupt agenda meant to confuse people. For that, you need to look at the marketing material you are reading about your favorite loudspeaker.
These are true researchers who happen to work at Harman with very deep pockets, able to conduct such research at grand scale. They are not sitting there fooling themselves or other people because you all happen to think of things they have not.
Also, some feel strongly that to properly evaluate the performance of a speaker, it should be the only speaker in the room because other speaker drivers move with sound pressure and can effect the sound or measurements of the speaker being evaluated. Does Harman really do the tests in that room with all of those speakers present? What about the other 70 pairs and all of the people in the room taking part in the DBT. Doesn't their presence also effect test results?
You honestly think they put 70 loudspeakers in one room and tested them with 250 people??? No, they did not. These are composites of many independent studies. Yes there are a few loudspeakers in the room. The only effect I have heard of here is the woofer acting as a tuned absorber but that happens when it is unloaded.
Perhaps I'm not in a position to criticize or question any of this.
What were the comments above then?
I'm not an industry professional and don't know much about the science of audio, so perhaps my questions are naive, or can be seen as coming from the bias of a skeptic and subjectivist. But the objective side of me would like to know how the NRC testing methodology differs from that being used by Harman. Has the Revel Salon 2 been tested in both facilities, and if so, are the measurements the same?
The Salon 2 came years and years after Dr. Olive and Toole performed their research there. From what I recall, the testing there relied on turntables rotating loudspeakers and the technique I mentioned: symmetrical placement in a room behind a curtain (i.e. two at a time).
Since this is a thread about reality, photos of actual tests being performed would help us to better understand how the measurements are made.
Loudspeaker is put on a lazy susan in an anechoic chamber. A series of frequency response measurements are then taken with that microphone array giving you a slice in 3D Space from horizontal to vertical. The turntable is then moved precise number of degrees and another array snapshot is taken. This is repeated until you have completed 360 degrees. Once there, you have 72 measurements of a 3-d space around the loudspeaker. These are independent data points. They are then combined into three different curves, when in turn are combined into weighted composite for prediction of loudspeaker preference/performance.
