# Testing microphone input soundcard



## upking (Apr 8, 2012)

So I was trying to know if my soundcard is suited for measurements, the graphics I'll show below are from the microphone in from my onboard soundcard, chip realtek ALC 1200 (some say it's the ALC888 renamed)

The input signal was provided by a Behringer UCA 202 which is known to have a really flat response. 
I ajusted the output level of the behringer so that it wont clip the input of the onboard sound card.
However I used very cheap cables to connect both cards, I'd say they're not shielded, they are simillar to this one http://www.powermusic.com.au/wp-content/uploads/2011/06/Cables_RCA.gif also I used the case jack, so I did not connected the cable directly to the mother-board.



Enough said, let's take a loot at the graphics.

No gain, No smooth









No gain, 1/48 oct smooth









+10db gain, No smooth









+10db gain, 1/48 oct smooth









Those strange peaks could be because of the cable... Anyway IMHO the "no gain" configuration showed up a good response, being acceptable from 20hz to 18khz. Less than 1db variation, I found it quite impressive for a onboard sound card, I might add that I bought this PC 3 years ago.

What do you guys think? Should I use to measure speakers?

(the microphone will probably be a panasonic wm-61a capsule)


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## Wayne A. Pflughaupt (Apr 13, 2006)

You mentioned you don’t have a mic, so what is providing the UCA’s input signal? The UCA does not generate a signal; it requires an input signal from an external source. So how can you adjust the “output level of the Behringer so that it won’t clip” if there is no input signal?

I might also ask – if I understand, you’re feeding the output of the UCA to the mic input of your laptop sound card? Why? The UCA would replace your laptop’s on-board sound card.

Have you read the REW Cabling and Connection Basics and the REW Help Files?

Regards, 
Wayne


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## upking (Apr 8, 2012)

Wayne A. Pflughaupt said:


> You mentioned you don’t have a mic, so what is providing the UCA’s input signal? The UCA does not generate a signal; it requires an input signal from an external source. So how can you adjust the “output level of the Behringer so that it won’t clip” if there is no input signal?
> 
> I might also ask – if I understand, you’re feeding the output of the UCA to the mic input of your laptop sound card? Why? The UCA would replace your laptop’s on-board sound card.
> 
> ...


The UCA is connected to the PC via USB. The output was the Line output from the UCA with the levels controlled not to clip the input of my soundcard.
Like that:








The UCA can replace my line out and line in, but it doesn't have a microphone input.

I have read those topics, I did this loop just to know if the mic in was suitable for measurements, if it was flat enough. What do u think?
Thanks for answering.


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