[linux-audio-user] recording guitar - level problems

[Paul Winkler]

On Thu, Feb 23, 2006 at 01:24:52AM -0500, Dana Olson wrote:
> On 2/22/06, Ken Schutte <kschutte at csail.mit.edu> wrote:
> > Hi,
> >
> > I've setup a new FC4 system with alsa, jack, etc, and a SB Live card.
> > I'm trying to play some guitar thru the line in (eventually into
> > sooperlooper, maybe audor, etc).  No matter what I've tried, if I try to
> > get any significant volume, it's distorted terribly (not to mention some
> > terrible humming - something else I have to look into yet...)

Are you plugging the guitar directly into the line in?
That doesn't really work well unless the guitar has active electronics
(i.e. there's a battery in there).
You need something that converts the guitar's output to line level
and matches impedance well. 
Typical ways to do this are:

guitar -> amp ; amp line out -> soundcard

guitar -> direct box -> mixer mic input ; mixer line output -> soundcard

guitar -> direct box providing line out (rare) ->  soundcard

guitar -> amp emulator; line out -> soundcard


> > There's seems to be a lot of places to set the levels: guitar, amp,
> > alsamixer (capture, line in), but I feel like I've tried it all.  I'd
> > like to go thru my amp first, which has a line out and headphone out.

The line out from the amp should work OK.

Have you tried recording other sources through your card's line in?
That would help you narrow down where the problems originate.

Once you get a clean signal into the computer, I recommend
playing with the CAPS plugin suite; lots of fun!
See http://quitte.de/dsp/caps.html#Emulation

-- 

Paul Winkler
http://www.slinkp.com