How To Record An Acoustic Instrument (Online Course Homework)

[Note: As I mentioned in this post I'm taking a free online Berklee course in Music Production. It includes weekly assignments that must be posted so that they may be peer reviewed by another class member. Since they require teaching one of the topics covered in the week's lessons I will be posting them here so you may see as well - hence the slightly odd format required by the course.]

 

Hi – I’m Betty Widerski from Boston MA USA. This lesson is for week 1 of Introduction To Music Production at Coursera.org. I’m going to demonstrate how to record an acoustic instrument, specifically a violin. Click on any photo to enlarge it!

The gear I am using includes:

  •       One MXL 603 condenser microphone
  •       One XLR cable
MXL 603 mic and XLR cable

MXL 603 mic and XLR cable

  •       Tascam US-122 Audio/Digital Interface
  •       MacBook Pro
  •       Audacity DAW (digital audio workstation software)
  •       Headphones
Audio interface, MacBook Pro, Audacity DAW, headphones

Audio interface, MacBook Pro, Audacity DAW, headphones

The MXL 603 condenser microphone picks up sounds in a cardioid polar pattern:

MXL603 polar pattern

While this pattern means that it will tend to ignore sounds from the side and rear, it is still more sensitive than a dynamic microphone (like an SM58) so I am using a sound barrier (sometimes called a gobo) to shield it from the traffic noise at the intersection outside of my room’s windows.

Homemade gobo

Homemade gobo

You want to find the best-sounding place to put the microphone. A violin’s best sound is projected from the f-holes, so I adjust the microphone to point down at them while I play.

violin f-holes

violin f-holes

mic placement

mic placement

 

 

 

 

 

The Tascam audio interface has two inputs, which accept microphones, instruments, or line level connections and can provide phantom power. The interface connects to the MacBook via USB and is powered by the USB port.

Tascam USB-122 Audio Interface

Tascam USB-122 Audio Interface

Once the Tascam is connected to the MacBook, I open Audacity and go to Preferences. I choose Input Device = Tascam so that the program knows which input source to use and Output Device = Tascam so the recorded sound will be routed to the Tascam’s Phones port instead of to the Mac’s headphone port or built-in speakers.

Setting Input & output devices in Audacity

Setting Input & output devices in Audacity

Although I do not need to listen via an output device while playing an acoustic instrument since I can hear it (unlike, for instance, an electric guitar) I plug headphones into the Tascam’s Phones jack in order to hear the playback from Audacity if  I am recording over previously-created tracks. The Tascam has a Direct Monitor function to allow you to hear audio input without latency – you can adjust the headphones level and the amount of direct monitor signal via the knobs at the upper left and right.

I set the input type to “Mic” for the channel to be used. Since condenser microphones need phantom power to operate, I make sure the Phantom Power switch on the interface is OFF and the Gain for the input channel is OFF  in order to avoid sending “pops” through the system. I connect the one microphone I’m using to the audio interface via an XLR cable then turn on Phantom Power.

Now I start playing the violin into the microphone and start turning up the Gain knob for the input channel until the green Signal Level light next to it starts to blink. Play as loudly as you expect to record – if the red Clip light next to the green light does not blink, continue to turn up the Gain and play loudly until the red light does start to come on, then reduce the Gain level slightly until the loudest sound does not cause the red light to blink, in order to avoid distortion.

Phantom power on, green Level light shows sound input, Red Clip light off.

Phantom power on, green Level light shows sound input, Red Clip light off.

Too much Gain - red Clip light is blinking

Too much Gain – red Clip light is blinking

 

 

 

 

 

 

Once the Gain is set on the audio interface, I record a test track with Audacity. I examine the waveform and listen to the recorded sound to make sure:

1. That I’ve got all of the connections and settings correct so that it is actually recording!

2. That the Gain is set correctly – the visible audio signal is not clipping (hitting the top or bottom of the amplitude range), does not sound distorted, or is not too low in amplitude.

Once I have verified all of my connections and settings, I start with a fresh track in Audacity and begin recording.

DAW recording

DAW recording

As I mentioned above, I wanted to record two tracks so after finishing the first I created a new track and recorded a second violin part while listening to the first via the headphones.

Two tracks recorded in one Audacity project

Two tracks recorded in one Audacity project

The resulting recording:

I hope all of that is clear – please let me know if there’s something you didn’t understand or for which additional information is needed. Thanks for reviewing my lesson!

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