Now, audio interfaces built into computers are bare bones basic. So you will notice on inexpensive mixer like my behringer eurorack there is an extra pre-amp to boost this on a few of the channels that can plug in a 3 terminal balanced connector(which most condenser mic's use). And this often requires a pre-amp to boost it up to a sweet spot. The actual mic is only going to put out a weak signal. This high voltage is somewhat historic, and often something less will work(like 9v say). My better condenser mics require this and I get that from a small mixer that has 'phantom power'. Condenser mic's can require a bias operating voltage(phantom power), something like 48v. This must be a reference to phantom power. For this reason, induction from fluctuating ground can be very evident. Especially condenser and electret microphones due to the small mass of the diaphragm and the fact that they are electrically charged or biased, yielding to high sensitivity of the device to electromagnetic disturbances. Don't attempt any crazy thing to break a ground loop, use only equipment designed to do so.Īs a note, transducers (microphone and mics) are very sensible to ground loops. I want to stress this again: for your own safety only use your devices as intended by the manufacturer. Notice that all these circuitry operates on the reference of the signals to prevent ground loop manifestation, they are not supposed to operate on the power rails. For example, this DI box have a ground loop prevention switch (GND Lift) that will keep separated grounds of the signal paths to avoid ground loop hum to leak in the audio. If you need to break ground loops use dedicated equipment. For example, it could be due to the use of long cables. This can happen for cause completely external to the equipment circuitry. Ground loops arise when the basic assumption on grounding does not hold due to various reasons, that is: when I plug something to ground the impedance between "equipment circuit ground point" and "actual ground point" is not actually very low (< 1-2 Ohms). If you touch a guitar and microphone and one is live the shock goes through the heart. So I would probably think twice with that setup. Electric shocks from guitars are not unheard of, especially when you add a microphone. by shorting a high capacitance capacitor by accident) is too high.Īn external sound card will probably strongly reduce EM susceptibility of your system, that's why you see them often recommended. It works very well (it actually shields from noise) but I would totally discourage doing it: the risk you might short something you don't want and produce irreversible physical damage (e.g. Few people online built a film foil shield around their card: you wrap the card with foil and then connect the foil to a ground point. Most noisy components are: power supplies, fans, hard drives.
If your soundacard can be moved around you could try to place it further away from sources of noise. This electromagnetic noise gets then induced back in the soundcard circuits, polluting the signal. Fans especially, being pretty much coils.
All components inside your pc case emit electromagnetic noise due to currents circulating in them. Internal soundcards are very susceptible to that, especially on desktop computers. Other than a noisy preamp, it could be electromagnetic noise.
I get it regardless of plugged in microphone Like one of those old TVs not as extreme as such but as annoying. Doctor.apparatus wrote:When I start Audacity for example and record something I get that hissy white noise in the background.