Making my Purified GAYA2 fully active

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JanRSmit
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Making my Purified GAYA2 fully active

Beitrag von JanRSmit »

In a post in the Acourate v3 thread i already mentioned the use of Acourate v3 including the the Crosover linearisation macro from sinc-pulse.
Between other priorities i spent some more time to deepen my understanding of Acourate, and although not fully validated created a summed result of the individual driver-xo combo validations. This involved the individual amplitude level adjustment and the time alignment of woofer and midrange relative to the tweeter timing.
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v01.PNG
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v01.PNG (275.89 KiB) 1454 mal betrachtet
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v02.PNG
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v02.PNG (306.99 KiB) 1454 mal betrachtet
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v02-WMT.PNG
SPL-Ampl-leveled-Delay-adj-Sommation-FDW-15-15-v02-WMT.PNG (219.7 KiB) 1454 mal betrachtet
Cannot wait to repeat the measurements but then with the total stereo filter in place and if ok i can proceed with the off-axis measurements, and then as final step the room correction. By then i hope i can schedule remote desktop session with Uli to assess my understanding thusfar of Acourate and of course learn even more,and specifically the time alignment.

Then final installation (of version 1;-)) followed by the listening,listening, listening ;-) (and of course followed by iterations, and hopefully at some time this year the new Purifi tweeter ;-))

Hmmm, great progress, !!
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JanRSmit
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Ho to measure the real SPL levels of drivers with Acourate?

Beitrag von JanRSmit »

Dear Acourate users,

I am learning Acourate more and more for active xo. Howver i have a question: How do i measure and correct if possible the sound levels of the drivers so they are on the same lavel?

Here my validation measurments of the individual drivers and their created filter:
192kH-WMT-validation-results-combined.PNG
192kH-WMT-validation-results-combined.PNG (282.04 KiB) 973 mal betrachtet
Relative to tweeter the midrange is about 13dB louder, and the woofer a 30dB louder, but the LogSweep Recorder settings are the same for all three.

When i apply gain correction, the result looks like:
192kH-WMT-validation-results-combined-30-13-0.PNG
192kH-WMT-validation-results-combined-30-13-0.PNG (178.04 KiB) 973 mal betrachtet
The left and right marker show the xo frequencies 433, 3464 hz.

Here the summed result:
192kH-WMT-validation-results-combined-Summed.PNG
192kH-WMT-validation-results-combined-Summed.PNG (205.34 KiB) 973 mal betrachtet
The drivers in reality do not have such difference in their SPL, so how do i measure the correct spl with Acourate?
And how do i apply gain corrections in the filter?

I could not find info on spl level measurement, probably overlooking some remark or instruction, but past days i was unable to find info.
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uli.brueggemann
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Beitrag von uli.brueggemann »

Hello Jan,

There is no function to display the real SPL (sound pressure level) in Acourate.
This would require that a mic is calibrated accordingly. Indeed there are calibrations which tell something about the mic sensitivity and so you might deduct the desired number from the voltage. But usually the mic is connected to a mic amplifier with a more or less precise volume adjustment.
So you easily loose the connection between SPL and the amplitude of the digitized signal.
At the end you need to calibrate the mic properly with each use, e.g. https://www.thomann.de/de/digital_sound_8930b.htm. Be aware that the calibrator dimension must fit to the dimension of the mic tip.

Thus Acourate shows the frequency responses with relative levels. So sweeps with different frequency ranges have a different content of energy and the displayed results will differ. Furthermore the option 'Normalize Pulse' in the recorder is usually active and the resulting pulse height gets normalized to amplitude 1.0. You can switch off the option. Then Acourate will apply the same gain since the last normalization.

At the end the easiest way to check the level between drivers by running a full sweep over all drivers as you are showing by the last picture in your message. You may apply an additional FDW of e.g. 5/5 to smooth the curve. Then you can zoom in the magnitude response and deduct the level differences.

BR
Uli
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JanRSmit
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Beitrag von JanRSmit »

Thanks Uli, i was already thinking in sort of same direction.
Will test the pulse setting as you describe. And use the level info of the mic to adjust. The BabyFacePro input gain is set to 0dB (correction 11dB).
My mic is calibrated by Icemedien, your response suggests to calibrate sensitivity (@ 1kHz) before each use.
Hmm are mic's so varying?

I have ordered a focusrite 18i20, so when arrived i have to get it up and running in my development environment ;-)
I send you my procedure(s) written in a word document by email. Is still in development ;-)
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uli.brueggemann
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Beitrag von uli.brueggemann »

JanRSmit hat geschrieben: 12.07.2024, 13:55 My mic is calibrated by Icemedien, your response suggests to calibrate sensitivity (@ 1kHz) before each use.
Hmm are mic's so varying?
No, the mic should not vary that much.
But my mic gain and the amplifier gain can be different with multiple measurements at different times. So I simply ignore the SPL topic.
I adjust the sweep level to loud and comfortable. And I adjust the mic gain to get a full signal but without clipping.

And when I need the SPL I simply use my calibrated SPL meter including the fsdt/slow A or C weighting.

Viele Grüsse
Uli
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JanRSmit
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Beitrag von JanRSmit »

uli.brueggemann hat geschrieben: 12.07.2024, 14:02
JanRSmit hat geschrieben: 12.07.2024, 13:55 My mic is calibrated by Icemedien, your response suggests to calibrate sensitivity (@ 1kHz) before each use.
Hmm are mic's so varying?
No, the mic should not vary that much.
But my mic gain and the amplifier gain can be different with multiple measurements at different times. So I simply ignore the SPL topic.
I adjust the sweep level to loud and comfortable. And I adjust the mic gain to get a full signal but without clipping.

And when I need the SPL I simply use my calibrated SPL meter including the fsdt/slow A or C weighting.

Viele Grüsse
Uli
I tested LogSweep without the check boxes ticked, and in that way i can measure relative spl differences.
Not the absolute levels.
The relative spl differences is ok for me, so i can adjust gain as a start. The measurements at listening position will most likely require some adjustments on top.
Indeed if i want absolute levels an spl meter will be used.
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