The variance position-to-position will depend heavily upon the room (and what is in it) and the speakers.
As part of developing ARCOS room EQ, Harman (Dr. Olive) tested this difference. Here was the outcome:Wondering about the single point vs multi-point room correction measurement situation. Are you giving up a lot by measuring only at the listening position? As usual it depends.
My REW measurement was from a single spot, not multiple (ala Dirac). As I explained I can't repeat a multi-point measurement scheme (without a fixture as Kal explained).
No, but that has been in my plans. A friend with a very good system uses Dirac, and I've wanted to measure the result with REW after correction vs with no correction. Obviously something you'd like to see. Disappointed someone has not done this yet.sorry if this has been discussed already but has anyone measured with DIRAC applied to see how closely the "after" measurement as claimed by DIRAC matches reality?
I have and that is what we have been discussing.sorry if this has been discussed already but has anyone measured with DIRAC applied to see how closely the "after" measurement as claimed by DIRAC matches reality?
I do agree with this. Taking measurements at the same positions only confirms that the EQ system has performed its specific function of correcting based on those positions. However, there is an implicit promise in EQ systems that they are sampling enough of the room to make a generally effective solution. It is the latter that we hope to attain.I don't think one should take confirmatory measurements for room correction systems at the same positions. I believe random sampling tests real-world efficacy and stability of a room correction better than repeating the microphone positions used for calibration.
sorry if this has been discussed already but has anyone measured with DIRAC applied to see how closely the "after" measurement as claimed by DIRAC matches reality?
"So, controlling how well Dirac Live made corrections by repaeting the measurement at the same 9 points used initially by Dirac Live is misleading and/or out of context? Oh boy.. "
Taking 9 measurements and applying a simple average may not yield the same result as taking 9 measurements and applying a proprietary algorithm to determine a corrective amplitude/phase filter.
Wondering about the single point vs multi-point room correction measurement situation. Are you giving up a lot by measuring only at the listening position? As usual it depends.
I used REW to measure in six positions. The center LP, one foot right of the LP, and one foot left of the LP. Then moved back one foot and repeated. So 6 measurements on a 3 x 2 foot grid. 12 feet from the speaker is the LP.
First all 6 measures with no smoothing. Which looks rather poor. Even for a given measurement.
View attachment 20253
But our ears don't really hear that. They have some smoothing capability. So I applied 1/6th octave smoothing. It looks better. This is about the kind of smoothing in the mids and above for our ears.
View attachment 20254
Then I used an ERB smoothing filter. It looks not terrible now.
View attachment 20255
That looks better still. Our ears will hear first arrival sound mostly plus do some smoothing themselves. So the last one may be close to our perception. Above 1 khz the ERB smoothed responses fit into a 2 db wide window. Below 500 hz the room modes will have an effect of course. And something of a transition in between.
I don't know what Dirac and other softwares do, but they probably do some sort of averaging or smoothing among other things. It strikes me that any of the ERB smoothed response measurements used to EQ the result isn't going to sound radically different (maybe barely noticeable) to any of the others or even an average of them all. So single point measurements probably work okay for this.
Here are my 7 "across the top of the sofa" measures from two years ago, with "flat" DSP.
Traces 1 through 7 are left to right, with trace 4 (orange) the center.
View attachment 20263
Impulse Response, far left, as an example:
View attachment 20264
Center, Vector Average, and Simple Average: (never looked at vector average before)
View attachment 20266
I don't think one should take confirmatory measurements for room correction systems at the same positions.
I have and that is what we have been discussing.
Ray, what is "center average"? How do you get it and how does it differ from "simple" average?
There is no Center Average, just a measurement from the center (prime listening position)
As a single one. It can't EQ them independently.Sorry if this has been answered already but how does Dirac handle multiple subs?
so basically its useless for a multisub setup...As a single one. It can't EQ them independently.