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Dirac producing large 90hz dip 4 years 6 months ago #31161

  • john.reekie
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The reason to do a single-point calibration with Dirac is so that you can see how it behaves under certain conditions.

In general (without Dirac), single-point measurement/correction is fine as long as you know what the behavior is elsewhere. When I've done it my room, the center location is actually fairly close to the average of a set of measurements taken over the listening area. (I'm talking about subwoofer i.e. < 120 Hz.) I suspect most people would find a location that is like that. Clearly the center location is not it for lintoft.

In the end, these are all just tools...
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?

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Dirac producing large 90hz dip 4 years 6 months ago #31168

  • nugat
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Again, sorry if what I describe below is me really working against the principles of Dirac, but I am puzzled by the results:

I ran some test tunes, and it was obvious that the null was at/just in front of sweetspot. If I were to scoot all the way forward, to a near field position, the response is quite nice and flat.

There is no smoothing applied to any of the curves below. Also, all measurements is one point only, directly in sweetspot.

Anyway, I pulled the speakers 40cm out from the front wall (this can not be a permanent position, but I could do this when wanting to get optimal sound) and, when sitting directly in sweetspot, aside from the nasty bump at 65, resutls were not too bad (no correction):



I ran a Dirac measurement, one position only, and optimized. After optimization, this was the curve (Dirac correction only):



I do not have the separate right/left measurements with me right now, but they were quite different, the left speaker being way louder to 70hz, then dipping more at 100hz, while the right has a dip at 150hz.

I tried to compensate using PEQ only, and the results seem better (this was done very quick and dirty, not much testing) (PEQ correction only):



I have seen that in some cases it is recommended to disconnect left/right in Dirac etc. Could this be one of these cases, and how would I go about doing that? Again, I am happy compensating for sweetspot, or a very narrow area only.


I was wondering why the response is near flat between 25-70hz in the Dirac corrected graph and looks uncorrected by Dirac above 70Hz? Did you apply the right curtain above 70-80 Hz? Or else you did one Dirac measurement for this filter rather than prescribed nine? For bass there is less varation between measurements of close spots like for one seat, but obviously Dirac would not do its job higher up.

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Last edit: by nugat.

Dirac producing large 90hz dip 4 years 6 months ago #31169

  • lintoft
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Correct, that graph is the Dirac result, using a single point only.

Standard nine point gives this graph:

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Dirac producing large 90hz dip 4 years 6 months ago #31174

  • nugat
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Correct, that graph is the Dirac result, using a single point only.

Standard nine point gives this graph:


Please correct me if I got something wrong here:
--when using Dirac you always follow the 9-point measurement
--you use "single seat" pattern
--you do full range optimization, no curtains
--you don't use Dirac for "after optimization/filter" measurements
--to check Dirac's effects you use REW, both single and multispot measurements

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Dirac producing large 90hz dip 4 years 6 months ago #31177

  • lintoft
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--when using Dirac you always follow the 9-point measurement

Yes, I did a couple of tests with just one point, hoping to optimize for just the initial measurement point, but I understand that this is not how Dirac works.

--you use "single seat" pattern

All posted graphs are from "sofa" pattern, except when I have stated that it is single point only.

--you do full range optimization, no curtains

Yes.

--you don't use Dirac for "after optimization/filter" measurements

Not sure what this means, but some of the graphs are with Dirac enabled, if that is what you are thinking about.

--to check Dirac's effects you use REW, both single and multispot measurements

I have not posted any multispot measurements, only single. When I did a multispot measurement, as mentioned above, and averaged it, the response was fairly flat.

...

Again, I was under the assumption that I should be able to get Dirac to create a flat curve for me at my sweetspot. If that is not how it works, I am ready to accept it, the result with just a standard nine point measurement sounds very good, and way better than the "better" curve I am able to create using PEQ.

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Dirac producing large 90hz dip 4 years 6 months ago #31189

  • nugat
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--when using Dirac you always follow the 9-point measurement

Yes, I did a couple of tests with just one point, hoping to optimize for just the initial measurement point, but I understand that this is not how Dirac works.
GOOD

--you use "single seat" pattern

All posted graphs are from "sofa" pattern, except when I have stated that it is single point only.
SLIGHTLY CONFUSING TO USE THE PHRASE "SINGLE POINT " FOR A MULTISPOT DIRAC
MEASUREMENT WHEN IT RELATES TO "ARMCHAIR" LISTENING AREA


-you do full range optimization, no curtains

Yes.
UP TO YOU.YOU MIGHT TRY EXPERIMENTING WITH CURTAINS BOTH ON THE LEFT WITHIN 20-40HZ RANGE AND ON THE RIGHT AT 200-300HZ, AND THEN AROUND THE CROSSOVERS OF YOU DRIVERS , BUT NOT ONLY THERE. YOU MIGHT FIND A BETTER SOUND (SOUND, NOT A MEASURED GRAPH) THAN WITH THE FULLRANGE CORRECTION. LESS IS MORE WITH DRC.


--you don't use Dirac for "after optimization/filter" measurements

Not sure what this means, but some of the graphs are with Dirac enabled, if that is what you are thinking about.
DIRAC IS ACTUALLY CAPABLE OF TRULY MEASURING ITS FILTERS' EFFECTS WITH SOME TRICKS/WORKAROUNDS.
(NORMALLY THE TARGET CURVE IS ONLY A SIMULATION). DIRAC DOES NOT ENCOURAGE IT THOUGH, REW IS A MUCH BETTER
TOOL TO DO SO. JUST START THE DIRAC PROCESSOR WITH THE CHOSEN FILTER ON AND MEASURE WITH REW.

--to check Dirac's effects you use REW, both single and multispot measurements

I have not posted any multispot measurements, only single. When I did a multispot measurement, as mentioned above, and averaged it, the response was fairly flat.
MULTISPOT IN-ROOM MEASUREMENT IS CLOSER TO WHAT YOU ACTUALLY HEAR.
DIRAC USES 1/8 SMOOTHING, COMPARE IT'S OPTIMIZED CURVE (SIMULATED) WITH AN AVERAGED 9-SPOT REW MEASUREMENT SMOOTHED 1/6. I TAKE A PHOTO OF THE DIRAC SCREEN FOR THAT.

...

Again, I was under the assumption that I should be able to get Dirac to create a flat curve for me at my sweetspot. If that is not how it works, I am ready to accept it, the result with just a standard nine point measurement sounds very good, and way better than the "better" curve I am able to create using PEQ.


Your measurements still look strange to me, why Dirac manages to smooth 25-80hz to within +/- 3dB, and above that the results are much worse. Typically it should be the other way round.
I would not worry about the narrow dips below 200hz. They should not be really perceptible. Try "psychoacoustic" REW smoothing of averaged measurements, that's how you really hear. Dirac most likely knows the dips are cancellations and won't try to correct them.
Try walking around the room and listen to the bass. If your listening area sounds average, neither strong nor weak in bass, that should be ok.
Can't do much more. Well, if you borrowed two more subs and put the three around the Geddes way, you might be surprised what bass is possible in a small cellar room.

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Last edit: by nugat.

Dirac producing large 90hz dip 4 years 5 months ago #31241

  • lintoft
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I tried experimenting with the curtain, and I got a good result having Dirac only compensate for 20-90 range. I then tried removing the same peaks using PEQ only, and to my ears, the result is identical (although when measuring, Dirac is smoother 20-35).

All over the results of Dirac on my new speakers surprise me. With my previous setup, Dirac had a huge effect, but now I really just need a couple of peaks removed.

Anyway, the result is that I have bought a 2x4hd for use with my new speakers, and now use the DDRC-24 for my old speakers in a new room, where it still has great effect.

Of course, not comparing apples to apples here, the old setup is satellites+sub, while the new is floor-standers.

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