Microphones and Recording Project

Creative Commons image from Flickr by Roadside Guitars

Summary

I recorded my voice with different microphones to see which sounded best with my voice. I put it in GarageBand and made a podcast. My role was the recorder.

Microphone Audition Podcast

My Favorite Microphone Specifications

Sennheiser e609

  • super-cardiod dynamic microphone
  • mics guitar cabinets face on/extremely close
  • provides isolation from other onstage signals
  • mics drums, like toms, well too

Terms and Concepts

Dynamic Mic. – In a dynamic microphone a thin diaphragm is connected to a coil of wire called a voice coil which is precisely suspended over a powerful magnet.

Condenser Mic. -Instead of using a coil, ribbon microphones use a small strand of very thin 2 microns thick aluminum ribbon.

Omni pattern – Responsive in all directions, sometimes picking up unwanted sound.

Cardioid pattern – Condensers use two charged plates, one fixed and one which can move acting like a diaphragm.

Bi-directional pattern – Most sensitive to sounds coming front the front and the rear. Less sensitive to sounds at the sides.

Transduction – Converting sound energy into an electrical signal or an electrical signal into sound energy.

Voltage – The sensitivity.

Phantom Power – +48v of energy sent down the microphone cable to a condenser microphone from the audio recording or mixing board.

Sensitivity – Output level. Voltage of output signal when exposed to a certain sound level. Can be expressed as decibels below one volt. Most microphone signals are less than one volt so a negative number is used (-50dBV). Higher number means microphone is more sensitive (-30dBV) and a lower number means a less sensitive microphone (-70dBV). This number is meaningless unless you know what sound pressure level (SPL) it was tested with. Most are tested at 94dB/1 Pa. 

Frequency Response – The range of sound a microphone can reproduce and how sensitive the mic is at certain distance. Flat response, equally sensitive to all frequencies. Shaped response, more sensitive to some frequency ranges, adds clarity to vocals. When made less sensitive to low frequencies, picks up less background noise. Some microphones let you adjust frequency response.

Transient – An abrupt change in level. Like a cymbal’s crash or a singer’s T’s or CH’s.

Placement – If the sound source (mainly vocals) is farther away (3-4 ft), the voice is still clear but you get more room noise, which may be good if you want reverberation. Move the sound source even further to get more reverberation. About half a foot away from the mic, is the normal place for a vocalist. You get less room noise and the voice sounds even clearer. Picks up subtle changes in the voice. Moving the sound source to right in front of the microphone will increase the bass (proximity effect), as well as giving the voice a more intimate feel. A pop filter will be needed to prevent some words from “popping”. Like the singer’s P’s.

Proximity Effect – The increase in bass when a sound source is moved closer to the microphone.

Output – More sensitive mics have higher voltage than less sensitive mics.

Characteristics – Sensitivity, Frequency Response, Output, Maximum sound pressure level.

Noise Rating – The signal (sound source) to noise ratio measured in decibels (dB). Noise is any sound in the background you don’t want. Electricity vibrates at 60dB so you want the ratio of the signal and noise to be higher than that. Preferably 90dB or higher.

Mic. Clip – Holds the microphone to the stand

Mic. Stand – Holds up the microphone so the speaker doesn’t have to hold it. Height can be adjusted.

Windscreen/Pop Filter – Reduces breathing and wind noises

Direct Box – Connected to the mixer. Balances various outputs an inputs from the microphone and the mixer.

What I Learned

I learned how to make a podcast in GarageBand, and I learned what job each microphones had and what it was best for. I also learned which mic sounded best with my voice. A problem I had was fixing the volume on the intro and concluding statements, but I solved it by asking my friends for help.

 

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