6. FAQ

Yes and no! Definitely maybe :-). If everything’s wired correctly and working as it should, the ribbon should not be affected by phantom power. BUT, there is absolutely no tolerance for small mistakes or slightly incorrect wiring. If only a small voltage impulse gets to the delicate aluminium ribbon, it is bound to break. So, as a mere caution, don’t apply phantom power to ribbon microphones. When you disengage phantom power, keep in mind that it takes about 60 seconds (sometimes more) before the phantom voltage actually disappears. Don’t rush!

Don’t panic and, most importantly, don’t pull the plug! Speak into the mic and see if it still works (it usually does). If yes, everything’s fine. Simply deactivate phantom power. Wait a while before you disconnect the ribbon.

Ribbons usually have a very strong proximity effect, i.e. if the source is close to the microphone, bass frequencies are boosted. Just step back a little, it’ll sound much clearer immediately. Ribbons require some space for a balanced frequency response.

Front and back only appear to sound different, because they are phase reversed. You’re hearing your own voice directly and via the electric signal chain mic – preamp – headphones. One side of the ribbon is in phase, the other is out of phase with the direct signal. The out of phase side will sound thin and distant. Engage the phase reverse switch on your preamp and the formerly thin sounding side will sound full and rich. The formerly full sounding side of the ribbon will now sound thin. So if you want to compare front and back, you have to engage the phase reverse switch in the process. Note that this only makes a difference for the person standing in front of the microphone. The phase relationship is of little consequence for the sound you capture on tape or hard disk.
However, front and back of a ribbon actually do sound a little different, but not by much. Often one side is a little bit brighter than the other. No big deal…

No, all microphones have self noise. The noise a ribbon produces is approximately equivalent to that of a condenser mic of about 18 dB-A.

Low noise and high gain are the primary virtues of a good preamp for ribbon microphones. Datasheets can’t compensate for individual listening tests, but they can help you to narrow down your choices. The most critical spec is “Equivalent Input Noise” (E.I.N.) The lower the input noise figure, the better the preamp’s noise performance. Note that we’re in the realm of negative numbers: -129 dB is lower and therefore better than -120 dB! Unfortunately not all manufacturers measure the same way. For measurements with a 150 (or 200) ohms resistor at the input representing the microphone impedance (“150 ohms terminated”), the best possible noise figure is about -129 dB. Some manufacturers measure with the input shorted. This method yields seemingly better figures up to about -134 dB.

No, that’s an urban myth. Ribbons should be used with preamp impedances that are at least 5 or, better still, 10 times the microphone impedance. Lower impedances lead to unwanted gain loss, and often the treble and bass response suffers, too. Ribbon manufacturers recommend using preamps with an input impedance of at least 1500 ohms.

Ribbon microphones should be stored so the ribbon element is in a vertical position. If the ribbon is in a horizontal position for a prolonged period, the aluminium ribbon may begin to sag, which could alter the ribbon’s sound. So, for most ribbons this means you should store them in a standing position.