# Calibration Soundcard with HDMI-Output



## goldfield (Oct 1, 2011)

Hallo at all !

At first, sorry for my bad english, but in the german Forum's i get now answer.

I am using a PC for playback my music.
Here i am using the HDMI-Port of my graphic card for the output to my Onkyo TX NR 3008.
The graphic card has only the HDMI-Port for Sound-Output and naturally no Mic-In.
When i want to try the REW, i must use the Mic-In of my OnBoard-Soundcard.

I am using a microphone with a calibration file.
But how i have to calibrate my soundcard ? 
And which soundcard i have to calibrate ? The OnBoard Soundcard with the Mic.In, or the Soundchip of my Graphiccard, with the HDMI-Out ? 


I will hope, you understand me, and you can help me with my question.

With best regards: goldfield


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## JohnM (Apr 11, 2006)

Easiest would be to skip soundcard calibration, but make sure that there is no feedback loop when using the mic - tap on the mic and check that no sound comes from the speakers.


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## goldfield (Oct 1, 2011)

> Easiest would be to skip soundcard calibration


OK, but then i am not shure, if my measurements are exact enough.

Well, i can calibrate the microphone input off my onboard-soundcard,
but is it practical, when i use the soundchip off my graphiccard for the output?
I downt know, how great are the possible differences in the frequency response will be.
I have read, that many soundcards or soundchips distort the frequency response, specially at the deepbass.

I want to create some Basstraps, because my last measurements shows a peak at 36hz.
But if i made no calibration of my soundcard, i downt know, if my measurements are exact enough.
Possibly ther is no peak in my roomacoustic, but in my soundcard, or at an other frequency than 36Hz.

Or do you think, that the differences are not so big, and i should try it?

I hope, my english is good enough, to understand my problem


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## JohnM (Apr 11, 2006)

Your soundcard will not have any peaks at low frequencies. The response will be smooth and flat, with a gradual roll off at the lowest frequencies. On modern PCs that roll off starts below 20Hz, on older PCs it may start a little earlier, worst case it might be 3dB down at 20Hz. 

If you would like to measure the response of the card you could do it by linking one of the line level outputs from the Onkyo back to the input of your soundcard, or just use the output and input of the soundcard - the roll off is primarily in the input rather than the output.


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## goldfield (Oct 1, 2011)

> Your soundcard will not have any peaks at low frequencies. The response will be smooth and flat, with a gradual roll off at the lowest frequencies. On modern PCs that roll off starts below 20Hz, on older PCs it may start a little earlier, worst case it might be 3dB down at 20Hz


O.K., if so, i will skip the calibration.



> If you would like to measure the response of the card you could do it by linking one of the line level outputs from the Onkyo back to the input of your soundcard, or just use the output and input of the soundcard - the roll off is primarily in the input rather than the output.


maybe I'll try that sometime


Thank you for your help !
With best regards: goldfield


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