recording multiple sources from same instrument

[Doug Young]

Originally Posted by kurth

Funny, I never considered the signal length between two sources ...obviously because it's moving at the speed of light....

If a mic is involved, the signal is moving at the speed of sound - about 1 foot/ms. A pickup tho, is traveling at the speed of electricity, closer to the speed of light. So a mic 2 feet away could be 2 ms behind a pickup, just enough to cause weird phase issues - like if you had a phase shifter pedal that was stuck in one "spot" instead of sweeping.

[kurth]

Originally Posted by Doug Young

If a mic is involved, the signal is moving at the speed of sound - about 1 foot/ms. A pickup tho, is traveling at the speed of electricity, closer to the speed of light. So a mic 2 feet away could be 2 ms behind a pickup, just enough to cause weird phase issues - like if you had a phase shifter pedal that was stuck in one "spot" instead of sweeping.

Doug...You're right. I never considered that foot as being important to the synchronization of the two signals. So this argues for a close mic placement then ? ...a dpa style mic for example, placed a couple of inches from the soundboard. Of course this brings up the question of the speed of sound traveling thru wood, in the case of transducers. The mag pickup would still be slightly ahead. I had skipped the thread on Sound Radix because, one, it's expensive and two, I didn't think it was relevant to my situation. I better go back and pick it up , because this would be relevant to mags vs piezos too, esp top mounted transducers, inside under the bridge, or placed on the top.
....so in all cases where multiple sources are being used, they need to be sync'd regardless the type of pickup being used. Maybe that's why optical pickups sound so interesting?
.... thanks man....you've been a great source of info. I hope when I put my songs out there, you'll find the time to listen and give me some good constructive criticism. Peace/k

[Doug Young]

Originally Posted by kurth

So this argues for a close mic placement then ?

Not necessarily. You can't get the mic close enough to be totally in phase with a pickup. Even 2 pickups are likely to be out of phase with each other for various reasons. As with anything, it depends on the sound you want. You might even like the sound of 2 sources blended out of phase! It kind of acts like a tone control as some frequencies are cancelled, others are reinforced. But for home recording, close micing is probably the best approach anyway, to minimize the impact of room acoustics. If your room sounds good, then more distant micing will bring more of that into the mix, but you at least want to be aware of the phase interactions no matter what you do.

....so in all cases where multiple sources are being used, they need to be sync'd regardless the type of pickup being used. Maybe that's why optical pickups sound so interesting?

Again, not necessarily. You might like the way two sources blend when they're out of phase. But in many cases, what you'll get is a thinner sound when out of phase sounds are combined. For example, in the electric world, people play with phase on pickups, strats especially. You blend two pickups that are out of phase and you get a cool funky "out of phase" sound that's heard on lots of records. Put them back in phase and the sound gets fatter. Just a different sound.

Phase is just something to understand and be aware of, especially when you start combining sounds in artificial ways, like blending a pickup with a mic. Easy to play with. Take a simple mono track, duplicate it, and then use whatever sample delay your DAW has, or nudge the track manually by very small amounts, listen to the mix of the 2 in mono. Also pan the 2 hard left and right and listen to what happens as you vary the phase.