Timur wrote:Really, I only wanted to emphasize that plugging a guitar into a line-in is not such a good idea. The rest of the discussion came up because of the feedback and because it's interesting and valuable to know about these things when you're learning about music-production.
yes, guitars need hi inputs, and yes I'm seeing if there's something i can learn.
Plugging low impedance outputs into high impedance inputs aka impedance bridging is common practice in audio, not because of filtering effects but in order to maintain voltages/signal strength.
can you point me a link to this bridging concept. again, it can be a language barrier (still, props that you're writing this in your non-native tongue, so many of you Euro-dude impress me with that.)
This is in contrast to impedance matching where you want to have maximum current/energy. But as far as I understood current doesn't matter with audio-signals, only voltage matters, you don't even want to have current as long you don't have to drive speakers with it. So if you plug a high impedance guitar output (which are common) into a medium/low impedance line-input you will lose signal strength, because voltage levels will drop at the input.
this is where I feel your electronics knowledge falls apart. you can't really disconnect current and voltage, not in working electronics. voltage without current is static electricity, or a battery just sitting on the ground. current without voltage is impossible because as the current flows it defines a voltage, it goes from higher to lower potential. then you introduce a medium impedance input, which is getting silly.
By itself that has nothing to do with the lowpass filtering thing on guitars, but with guitars plugged into capacitative cables (and whatever else there is that can act like a capacitor in the electric circuit of a guitar) this can happen.
Timur, this frustrates me, you're saying you don't know what a capacitor is in a guitar yet you're using it in your posts. impedance DOES play a role in the low pass filter formed in the circuit, this includes any resistances, capacitance and inductance.
My PM comment on the 3m cable was less about the length (anything upto 10m and sometimes should work fine with many guitars), but more on the quality of the cable. My new 3m low-capacity guitar-cable audibly enhances the sound of a "hot" and dark-sounding neck humbucker on my old 70' Pearl LP Customs
compared to my old cheapo cables. That's less about cable-vodoo but more about quality vs. cheap crap.

And since you don't need any length of cable when plugging directly into your computer it's not a bad idea to use a shorter cable for lower capacity and thus saving any hassle with possible lowpass-filtering that might occur.
dunno, I've never compared cables, I need a new lead, when I get it, I'll compare. personally, I think this is snake oil BS, but I trust you enough to give it a try or not blow it off.
Whatever, normally if you plug an instrument/mic into any input you want to make sure that the input impedance does not match the output impedance, but is at least five to ten times higher. Else you may need more pre-amplification, including the higher noise-level that comes with that (plus the noise from the current running through resistant cables and electronics I guess).
where are you getting this?
By the way, most mic-preamps come with an impedance of around 2 kOhm and expect mics with an output impedance of around 100 to 200 Ohm. Line-level inputs come with an input impedance between 10 to 80 kOhm (i.e. Fireface uses 10 kOhm, the FX-Return of my Attax Guitar-Amp uses 47 kOhm).
see, shit like these and I take you've been reading up and have something to say, stuff I can learn.
check this out, it talks about bridging and the '10 times' rule you mentioned
http://www.tape.com/resource/impedance.html
I'm watching NFL (American football playoffs) game though, can't read too much.