DavidCarlJohnson
Posts: 8
Joined: Mon Jan 26, 2015 9:07 am

audio recording

Tue Feb 10, 2015 9:23 pm

So I'm trying to record audio through my USB soundcard. Works fine with a line in connected to my phone but not when connected to my guitar, I thought guitarix might fix the problem, but to no avail. Any ideas?

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r3d4
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Re: audio recording

Tue Feb 10, 2015 9:35 pm

What sound card do you have .. more info might help others help you

DavidCarlJohnson
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Joined: Mon Jan 26, 2015 9:07 am

Re: audio recording

Tue Feb 10, 2015 9:40 pm

Sorry, its a CM108

The only thing I can think of is that the audio signal from the guitar isn't loud enough, it guitarrix/audacity work fine when I use a line In with a phone

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r3d4
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Re: audio recording

Tue Feb 10, 2015 9:48 pm

ahh ok i c , sound like you need an amp :?: :?:

Ravenous
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Re: audio recording

Wed Feb 11, 2015 11:38 am

DavidCarlJohnson wrote:Works fine with a line in connected to my phone but not when connected to my guitar
Is it just because the guitar's output level is far too low? As R3D4 said, you might need some sort of preamp. If you have a distortion or compresor pedal handy you might be able to use that to boost the volume and see if anything gets recorded?

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r3d4
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Re: audio recording

Wed Feb 11, 2015 5:53 pm

see also DI box

jimallyn
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Re: audio recording

Wed Feb 11, 2015 7:58 pm

Electric guitars typically put out enough to drive a line level input, but the pickups are fairly high impedance, so plugging them into a low impedance input will cut their output markedly. Do you have the input impedance specs for your sound card? Does the sound card have an input specifically configured for guitar input (high impedance)? If you post the model of your sound card, we could track some of this information down.
“So you say you love the poor? Name them.” - Gustavo Gutierrez

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r3d4
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Re: audio recording

Wed Feb 11, 2015 11:27 pm

jimallyn wrote: If you post the model of your sound card, we could track some of this information down.
- http://www.raspberrypi.org/forums/viewt ... 23#p691242

drgeoff
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Re: audio recording

Wed Feb 11, 2015 11:38 pm

CM108 is a C-Media IC. It doesn't identify a specific USB sound card implementation.

jimallyn
Posts: 51
Joined: Wed Nov 12, 2014 9:13 am

Re: audio recording

Thu Feb 12, 2015 6:14 am

I did a little Googling for CM108. The CM108 is an integrated circuit, not a sound card, and it does not have a line input, it only has a mic input. If your interface has a line input, then it must have additional circuitry in it for the line input. Is there a manufacturer name and/or model number on the interface?
“So you say you love the poor? Name them.” - Gustavo Gutierrez

DavidCarlJohnson
Posts: 8
Joined: Mon Jan 26, 2015 9:07 am

Re: audio recording

Thu Feb 12, 2015 7:37 pm

Hi all, a small USB powered speaker acting as a preamp did the job. Thanks for the help!

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