On Fri, Jan 02, 2004 at 11:40:18PM -0800, Mark Rainess wrote: > You may need to use an impedance matching transformer, > or a microphone preamplifier, between your guitar and > the microphone input on your sound card. Your sound > card probably has a "high impedance" input, and I > think all electric guitars have "low impedance" > outputs. Most good microphones also have "low > impedance" outputs. > > ... (lots of stuff about impedance matching) >
Microphones are usually low impedance. A dynamic mic itself will be in the 150 to 600 Ohm range, and condenser mics (which have a preamp built in) even lower. A pro mic input will be in the range 1 to 5 kOhm. So mic inputs are normally voltage driven, and *not* impedance matched for maximum power transfer. In fact the only place in audio where impedance matching is still required is when driving a signal over very long lines. Everything else is voltage driven. Guitars are traditionally high impedance (at least at high frequencies) and should not be connected directly to a mic input. Use an active DI box. Mic inputs on most sound cards are designed to be used with cheap electret mics, and some may also supply a small DC voltage on top of the signal. They are even less suitable for a guitar. All this said, I don't think the problems reported by the original poster are related to this. If JACK reports repeated xruns, this has nothing at all to do with electrical impedances. -- FA ------------------------------------------------------- This SF.net email is sponsored by: IBM Linux Tutorials. Become an expert in LINUX or just sharpen your skills. Sign up for IBM's Free Linux Tutorials. Learn everything from the bash shell to sys admin. Click now! http://ads.osdn.com/?ad_id=1278&alloc_id=3371&op=click _______________________________________________ Alsa-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-user
