Mic plugged in the guitar input does not work

Question

I have a newly bought Scarlett Solo, in which I plugged an SM57 using an XLR to jack cable, in the guitar input. When I handle the mic, I see the LED from the gain knob lighting up, probably from static stuff. But when I speak in the mic, I get no sound.

Tried everything, installed the Focusrite USB (ASIO) driver, I made sure to set the proper input device in Windows 10 (default recording device) and output to my headphones, I switched to the Instrument line on the interface, I bumped the gain to the maximum, etc.

The interface looks like this:

The cable has these connectors:

I plugged the XLR female in the SM57 mic and the jack in the interface guitar input. First installed all the drivers and set the interface as the default audio input device. Then I tried to record in Adobe Audition, Audacity and in Reaper. No sound whatsoever from the mic.

Could it be that the mic is not working? The interface works ok, as far as I can tell. I logged in another mac system and tried to make it work there too, but same result. No sound. It seems the cable works, because it produces static noise when I move the mic around and the interface picks up that noise and shows that in the input LED. Some of that noise gets recorded even. But nothing seems to go through the mic capsule. It's as receptive as a rock. How can I tell if the mic is not working?

Thanks.

Answer 1

I'm not sure who sold you that XLR to 1/4" cable, but it flat out isn't right. XLR is a balanced signal, which means it has 3 different conductors. The 1/4" connector it is adapting to only is a Tip/Sleeve connector which only provides 2.

Additionally, the levels between a microphone and a guitar are completely different and not really compatible. With a proper cable you should be able to hear a little bit as long as your mic doesn't require phantom power, which the SM57 does not, but it would be very quiet and likely noisy. This is why a guitar is usually plugged in to a direct box prior to going in to a sound board.

Your particular audio interface has an input for both balanced microphones via XLR as well as a 1/4" input for guitars and/or line level signals depending on how you set the switch.

You need to use a normal XLR cable and plug your microphone in to the XLR input on your audio interface.

Answer 2

Plug your Microphone, using a XLR(Male)-XLR(Female) cable into the Microphone input.

It is the input with the little Microphone picture as shown here:

Using any other input will not work.

Answer 3

A microphone is no guitar. Guitars are high-impedance high-voltage, unbalanced connection. Microphones are low-impedance low-voltage, balanced connection. The balanced connection is pretty important at typical microphone levels in order to keep hum and noise in check.

The cable you are using is for plugging the TRS output of a mixer (for example) into an instrument amp: high voltage, often low impedance. The cable basically is the "I think I don't have a ground loop I need to break up" cheap equivalent of a DI box.

Unsurprisingly, the cable from the microphone actually belongs in the socket with a microphone painted on. The cable to be used for that is an XLR (or microphone) cable with one female and one male XLR connector (XLR cables can be expected to always be that way).

The SM57 is a dynamic microphone, so you won't need to turn on phantom power (the 48V switch/indicator). It shouldn't usually be damaged by it, but no need to take chances. Also turning off phantom power will make your laptop battery last longer, and depending on the quality of the interface, there might be a bit less noise.