# Question for someone who has intimately familiar with how auto calibration software works.



## aceinc (Oct 24, 2006)

I have always wondered why all (at least the ones I have played with Audyssey, MCCAC YPAO) the auto calibration software seems to only run a single pass per channel? Yes I know some of them will allow you to adjust the position of the mic and run multiple passes but that is not what I am referring to. 

As a software developer myself, I would think that the calibration software would run multiple passes per channel. The first with no calibration to analyze the raw signal of all the components in the circuit. It would then apply the correction it decided was best and run the analysis a second time to see how well it did. If needed it would apply additional correction and try the analysis again. It would do this until it couldn't get any better or "n" times whichever came first. I am familiar with the law of diminishing returns, but I have also seen people pay thousands of dollars for power cords.

I just can't imagine that every combination of components would behave in a similar manner to the corrections applied. If this assertion is true having the software run successive passes using the previous results as the base for the current pass, seems as though it would provide better results.


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## Kal Rubinson (Aug 3, 2006)

What you suggest is reasonable but none of the consumer-level systems do that because (1) they do not calculate the correction for each channel until they have measured the response of all the channels and (2) none of them *ever *apply and measure the post-correction response! 

They all presume that the predicted text-book measurement/calculation/correction is perfect. The only way to monitor the results is with a separate measurement system, like REW.


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## aceinc (Oct 24, 2006)

Are there non-consumer products that do this?

Sounds like an opportunity for clever developer, to improve on the status quo.


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## Da Wiz (May 8, 2019)

The solution was already posted... REW combined with a measurement microphone like the $50 Behringer mic... do measurements before calibration software is run for the baseline response. Run the calibration software, then run REW measurements again. Compare the before and after REW measurements.

Some calibration systems try only to correct frequency response.

More advanced calibration systems try to correct time domain and frequency domain errors. Time domain errors would be unintentional delays and phase errors. They can even make speakers that are NOT time/phase accurate and make them accurate in the time/phase domain. Seeing frequency and time domain improvements in REW requires some understanding of room acoustics and measurements. There are REW forums to help people get the understanding needed to use REW.


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## Sam Ash (Aug 23, 2009)

People say good things about Dirac - is it any different. I know that they are working on their next level Dirac solution.

Anyone here who has done a thorough comparison between Dirac and the alternatives ?


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## Kal Rubinson (Aug 3, 2006)

Sam Ash said:


> People say good things about Dirac


 Yup.


> - is it any different.


 Not in this regard.


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