Frequency correction for 1/3 octave

HansJAvanLeeuwen

Ben,

I'm sorry, I'm sure your calibration measurements are in error. And your presentation is also incorrect!

You, as an acoustician, should know this too. I think we shouldn't publish vagueness about this. A positive and professional approach will benefit the field!

Hans J.A. van Leeuwen

benfaber

Hans,

Your opinion has been noted.

Since you have made it clear that you believe my measurements (and presentation) are in error, you are welcome to share your specific arguments and evidence to the contrary.

Thank you.

Ben

HansJAvanLeeuwen

Ben,

I gave you some figures; the correction of the internal microphone of an iPhone at 50 Hz and at 100 Hz. And I gave you the reasons why your figures are incorrect. Please give me some reasons why you think you handled it correctly.

The IEC 61094-5 standard, "Methods for pressure calibration of working standard microphones by comparison," was used. This standard only allows you to compare the same microphones, so the method is flawed when comparing two microphones with different constructions and dimensions. Moreover, the protective grille is removed from the reference microphone, while this is not possible at all from the iPhone microphone.

And the question is whether the microphone correction is published too optimistically. This is because the axis label is described as "magnitude Pa/Pa" and not in dB. After all, a measurement in dB is a magnitude based on the pressure squared.

So once again, be honest!

Hans J.A. van Leeuwen

benfaber

Hans,

I don't mind having a discussion with you regarding the merits of the measurement data that I have published.

Please understand, however, that I have no appreciation for your suggestion that I have in any way been dishonest!

I have already responded to your questions/concerns with respect to the Magnitude label (it is indeed in dB, as I indicated). The label should show dB. The fact that it doesn't may suggest a minor cosmetic bug in SignalScope that I need to make sure gets corrected.

I have also already responded to your concerns about the differences between your measurements at low frequencies and my own. I requested more detail regarding your measurement procedure, which you have still not provided, except to say that you measured an iPhone 14, for which I have not published any measurement data.

I have also already responded to your concern about the procedure given in the standard as well as your concern about Pa vs Pa² (anyway, 20log10(Pa) = 10log10(Pa²), as you have already noted, so what's your concern with that?).

You clearly disagree, but I haven't seen specific arguments that lead you to believe that my values are wrong other than these vague disagreements that I have already addressed. I'm not sure what your goal is, here, but this discussion has ceased to be productive. Perhaps, we're not understanding one another. I'm not sure what more to say than what I have already said.

Best regards,

Ben

HansJAvanLeeuwen

Ben,
I stated that the IEC 61094-5 standard cannot be used for this type of comparative measurements. I explained why. Therefore, I believe it is better to withdraw these measurement results and perform new measurements.
I am very curious about the results,
Kind Regards,
Hans

benfaber

Hans,

The concerns with respect to the standard may affect the measurements at the highest frequencies, as we have discussed. Your concerns about how your low-frequency data differs from mine has to be explained some other way, which is why I asked you to provide further details about how you performed your measurements.

As I have already indicated, I do plan to explore this further with additional measurements. Other concerns have priority on my time, right now, so I can't say when that will happen. In the mean time, I do not agree that the current measurements need to be "withdrawn."

Best regards,

Ben

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