I do not have a background in audio recording, but I need to record high-frequency noise that has invaded my condo from the two students who live upstairs from me. This is not tinnitus. This has been going on for the last three months. I desperately need it to stop. I have a new iMac and Blue Yeti microphone. When I record, however, the high frequencies do not play back. I've tried many different gain levels and placed the mic in various places in my condo. What am I doing wrong? Please help!
I do not think it is possible to record the noise you hear and if you want to know why I will explain in detail below
The Yeti has different sensitivity with different settings. Make sure it is in position 2 which should be Omni directional which is the most sensitive according to the manual.
Ideally humans can detect sounds at a level as low as 20 micro pascals (0dB). The Yeti produces a mic-level voltage, which is very low, at 1 pascal (94dB). A whisper is probably around 40dB. The further away the sound source is from the microphone the less sensitive it is. Try whispering to a microphone from over 2 meters away and you will probably not be able to play back the sentence without huge amounts of background noise.
I’m not sure where the sound is coming from or what frequency it is but increasing distance and frequency lessens the chances of capturing the sound.
I would suggest downloading a tone generator app and matching the generated sound to what you hear and see what frequency that is and then try to isolate that on your recorded file to see what you have captured at that frequency.
To make sure the frequencies you want are being recorded:
- make a recording.
- open this file in an audio editing application. Audacity is a nice, free one.
- use a spectrum analyzer to check at which frequencies sound occurs in the recording. In Audacity: Analyze->Plot Spectrum. This is limited in that it isn't real-time, it can only provide a spectrum of your recorded sound. Other programs can provide a real-time spectrum analysis (RTA).
If your neighbors are making high-frequency noise, it will show up as a spike in the spectrum.
Generally, if you can hear a sound, most microphones will be able to pick it up. Many mics are less sensitive at high frequencies (over ~10 kHz).
When you play back the recording, use headphones. This reduces the amount of ambient noise, and allows you to better hear what's in the recording.