Recording a Flute

Today, we set up to record a flute using two microphones: A Rode NT1-A and a CAD GXL3000. The reason we chose to use these two microphones is because on their spec sheets they are very similar, but in reality give a very different sound and we wanted to see for ourselves how different they really were.

We set up both microphones (shown below) on their stands, each mounted in a shock mount and with a pop shield between them and the performer. A lot of people make the mistake of thinking that the sound from a flute comes from the open hole at the bottom of the instrument, but this is not the case; the sound comes from the mouthpiece, where the performer blows through when they play. With this in mind, we positioned the microphones opposite the mouthpiece while the pop shields each protected them from any unwanted "pops" in the recording that is caused by the performer blowing into the microphone.

(Ignore the vocal shield and the unused pop shield behind the two microphones, they weren't used in this setup)

After providing our performer with a set of headphones so that we could talk to them whilst in the studio, we began recording. After recording the piece and listening to each microphone separately, we found that the NT1-A was a lot louder than the GXL3000 despite the gain levels being the same. We consulted the spec sheets for the answer to this problem and soon enough, we found it. Even though the sensitivity of the two microphones were almost identical, they had very different "Self-Noise" or "Equivalent Noise Level". This refers to the noise that the microphone itself produces, which it then reduces everything by that value so that it doesn't interfere with whatever is being recorded. Our problem was that the NT1-A, which prides itself as being the world's quietest studio condenser microphone, produces a tiny 5dB of self-noise whilst the GXL3000 produces a much louder 20dB of self-noise, resulting in it being 15dB quieter than the NT1-A.