[linux-audio-user] stompboxes2 and audacity question

[Paul Winkler]

On Fri, Nov 14, 2003 at 10:36:08AM -0500, Joe Hartley wrote:
> The signal from a guitar or bass is not at line level; it's equivalent
> to a microphone level input.  

It is neither. Guitar pickups are roughly 10 kilohm impedance, 
while microphones are roughly 500 ohm impedance.
Both microphones and guitars are sensitive to the load you connect
them to. Mic preamp input impedance ranges from about 500 ohms
to about 5 kilohms.  Guitar preamps and DI's have input impedance 
ranging from 500 kilohms up to several megohms. 

So - don't do the following:

 passive guitar -> line-level input
 ... decent loading, low signal level, high noise

 passive guitar -> mic preamp
 ... good gain, really bad loading; frequency response
 suffers.

 active guitar -> mic preamp
 ... too much gain! probably distorted. not sure about the loading.


The following are reasonable solutions:

 passive guitar -> DI box -> mic preamp
 ... good loading, good signal level

 active guitar ->  line-level input
 ... good loading, good signal level

 active guitar -> DI box -> mic preamp
 ... good loading, good signal level, a bit noisier


-- 

Paul Winkler
http://www.slinkp.com
Look! Up in the sky! It's BRITISH LEOPARD!
(random hero from isometric.spaceninja.com)