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Dirac Live, FIR-filter - Yes, No?

Sal1950

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#61
Sorry if this has been answered already but how does Dirac handle multiple subs?
As a single one. It can't EQ them independently.
That is correct. But I'm sure I read someplace that Dirac Live 2, or whatever it's called, is in final development and will handle up to 6 subs independently. My Audyssey XT32 + Editor app does 2 independently.
 

Ron Texas

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#62
That is how the science works. Great quote from Dr. Toole's book:

View attachment 19951

May also want to read my article on the same topic: https://www.audiosciencereview.com/...ds/perceptual-effects-of-room-reflections.13/

There is a big difference between sound reproduction in rooms and electronic devices. You will see that reflected in my views.
This could be the most interesting post in an unusually technical thread. The brain adjusts for the environment. I would think the better speaker designers have taken this into account, especially with regard to average size rooms.
 

Krunok

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#63
I would think the better speaker designers have taken this into account, especially with regard to average size rooms.
How exactly would you suggest speakers manufacturers take this into account? :)

And what exactly is "this" telling us? That speakers don't need to be linear as ear is forgiving? In that case why do manufacturers struggle to deliver linear response in anechoic environment and why do we struggle to make room EQ?

I can't believe there is no study to show which room curve listeners preferred after EQ..
 
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Ron Texas

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#66
Weren't the speakers manufaturers always aiming for linear anechois response? Or are you referring to some other thing other than that..?
Not all of them are aiming for linear response. Just look at B&W, the BBC hump, and the Kef 2k-5k bump. The later one has two members around here very excited and on a campaign to stamp out the LS50.

Speaker designers test in an anechoic chamber, but listen to their work in a room. I strongly suspect they use a variety of rooms, some treated, and of different sizes. Why wouldn't they?
 

stunta

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#67
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.
Wouldn't it make more sense to weight the MLP more? By applying multi-point measurements, there has to be a trade-off making the response at the MLP sub-optimal. However, since the EQ system knows what your MLP is, I would think it would give it more weight - still sub-optimal for MLP but not as much.
 

Krunok

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#68
By applying multi-point measurements, there has to be a trade-off making the response at the MLP sub-optimal.
Not necessarily. IMHO it all depends how much of the space you cover with multi-point measreument. You can cover a small space with the foot print of your sofa but you can go wider as well. Even if you want to optimise only for MLP I believe you shouldn't cover much less than sofa footprint and az least 30cm of height around the center point of MLP.
 

DonH56

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#69
I do not know what the actual algorithms are and they are not likely to disclose them. However, Dirac Live is very explicit about making the first measurement at the MLP, which to me implies they are indeed weighting it more heavily.

In a live room, or one with significant sources of reflections (like a coffee table in front of the MLP), the frequency response can vary dramatically when you move a few inches due to comb filter (SBIR) effects.
 

Krunok

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#70
I do not know what the actual algorithms are and they are not likely to disclose them. However, Dirac Live is very explicit about making the first measurement at the MLP, which to me implies they are indeed weighting it more heavily.
Maybe. But may as well be it simply the first point to measure to ensure that users will correctly follow the measruement procedure. For the same puspose their points are numerated but that doesn't necesarrily imply that last one is least significant nor that first one is the most..

In a live room, or one with significant sources of reflections (like a coffee table in front of the MLP), the frequency response can vary dramatically when you move a few inches due to comb filter (SBIR) effects.
That's true, but isn't that the argument to go with moving microphone method with 70+ samples instead of averaging the sweeps in a few points?
 

Sal1950

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#71
However, Dirac Live is very explicit about making the first measurement at the MLP, which to me implies they are indeed weighting it more heavily.
Yes, Audyssey does the same. The first of the 8 recommended is always the MLP. Three points is the minimum that the software will accept before you can end the measurement routine and do the final calculations..
 

Krunok

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#72
Btw, I become sceptical when I'm seeing "experts" using automated room EQ tools. I would real expect experts to do the job by themselves using manual filter creation tool.
 

Sal1950

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#73
Btw, I become sceptical when I'm seeing "experts" using automated room EQ tools. I would real expect experts to do the job by themselves using manual filter creation tool.
Way too big a PITA for me. I believe things like Dirac Live or Audyssey+Editor app, fine tuned after measurements with REW, can get the job done to a acceptable outcome.
YMMV
 

stunta

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#74
Btw, I become sceptical when I'm seeing "experts" using automated room EQ tools. I would real expect experts to do the job by themselves using manual filter creation tool.
I am encouraged to try the automated room EQ tools when the "experts" use them. It means its as good as, if not better, than following several steps manually which can be error-prone. Re-using well implemented automation is not an indication that the user is not an expert in the field - it is just the more optimal approach. I design and develop software for a living and the really good ones I work with are always looking to reuse well-known APIs rather than spinning up their own. They can write it themselves if they choose to, but why reinvent the wheel?
 

Krunok

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#75
Way too big a PITA for me. I believe things like Dirac Live or Audyssey+Editor app, fine tuned after measurements with REW, can get the job done to a acceptable outcome.
YMMV
I also believe they can, but it cannot beat the result of a true expert doing things mannually.

Not to forget that it cannot give the same satisfaction. ;)
 

Krunok

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#76
I design and develop software for a living and the really good ones I work with are always looking to reuse well-known APIs rather than spinning up their own. They can write it themselves if they choose to, but why reinvent the wheel?
This is a very poor analogy.
 

Kal Rubinson

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#77
However, Dirac Live is very explicit about making the first measurement at the MLP, which to me implies they are indeed weighting it more heavily.
Yes, Audyssey does the same. The first of the 8 recommended is always the MLP.
All that is based on the fact that both systems use the first mic position to define the MLP for purposes of setting time delay and levels. I do not infer more than that although it is possible.
 

Flak

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#78
Are you saying science doesn't work with speakers? Logic thinking also doesn't work?

How about this? Dirac Live requires you to take 9 measurements over the listening window. It than averages them in order to make a correction filter.
That's not correct, Dirac Live takes nine measurements in order to be able to understand what should be corrected and what not, it does not average them in order to make a correction filter.
The above applies to both impulse response (often overlooked, I did'nt see it in your graphs) and magnitude.
More details about Dirac Live here:
http://diracdocs.com/on_room_correction.pdf

There is a simple way to verify how good job it has done: take the same 9 measurements with REW with Dirac Live correction active, average them and check how close they are to the predicted response.
Response predicted by Dirac Live is quite accurate, the subject is discussed for example here:
https://audiophilestyle.com/forums/topic/22467-dirac-lives-graphs-how-accurate/
As you mention one can use REW but conditions have to be the same, also measuring in one single point in space is useful and possible for double checking the accuracy of Dirac predictions but is not valid for an appraisal of the listening results.. both IR and FR will change considerably even at the distance of one ear vs. the other.
We usually use both and don't put our head in a vice :)

These are two measurements taken at 30 cm. distance, which one should one choose for correction and evaluation of the results?

30cm_dia.jpg


Ciao, Flavio
 
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Flak

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#79

Krunok

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#80
That's not correct, Dirac Live takes nine measurements in order to be able to understand what should be corrected and what not, it does not average them in order to make a correction filter.
The above applies to both impulse response (often overlooked, I did'nt see it in your graphs) and magnitude.
More details about Dirac Live here:
http://diracdocs.com/on_room_correction.pdf



Response predicted by Dirac Live is quite accurate, the subject is discussed for example here:
https://audiophilestyle.com/forums/topic/22467-dirac-lives-graphs-how-accurate/
As you mention one can use REW but conditions have to be the same, also measuring in one single point in space is useful and possible for double checking the accuracy of Dirac predictions but is not valid for an appraisal of the listening results.. both IR and FR will change considerably even at the distance of one ear vs. the other.
We usually use both and don't put our head in a vice :)

These are two measurements taken at 30 cm. distance, which one should one choose for correction and evaluation of the results?

View attachment 21384

Ciao, Flavio
Salve Flavio! :)

Heh.. So much text and yet so little usefull information. But ok, it is understandable that you cannot really disclose the details how your product works.

In my opinion it would be very usefull if Dirac would implement control measurement procedure so users can verify how good of a job is filter generated by Dirac is actually doing. As long as that doesn't exist users are left on their own and the only thing they can do is either measure the log sweep in same 9 points and average them or they can apply RTA moving microphone method in the same space within those 9 points. In my opinion and in my experience both of these methods would result in a very similar curve and would provide very good insight of Diracs results.

If that would be implemented then users would have a possibility to repeat the measurements procedure to give Dirac a chance to self evaluate it's own work. That would also serve as an indication to user if he should consider relocating the speakers or doing some other actions to improve possibility to get better sound.
 
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