32bit Float Audio recording for EVP recording

As complicated as audio recording is, here is another area of the audio recording process that may leave you scratching your head but will change how you record audio in the field forever.

32 Bit Float, unknown to most, is simply a recording bitrate, similar to 8, 16(compact discs) and 24 but 32bit float adds more precision in audio recording with a massive dynamic range. Dynamic range in audio is the range between the softest sound to the loudest.

To measure the noise level of different sounds, we use a measurement unit called the decibel (dB). Each time a sound’s decibel level increases by 10, its intensity multiplied by 10. However, the decibel scale is logarithmic, not linear. Therefore, a 10 dB sound is 10 times more intense than a 0 dB sound, a 20 dB sound is 100 times more intense, and a 30 dB sound is 1,000 times more intense.

We use the decibel scale to determine how loud sounds are and if they are safe or harmful to human hearing. The range of sounds measured on the decibel scale is from 0 dB (the quietest sound) to 140 dB (the threshold of pain).

16-bit audio is capable of recording sound with a dynamic range of up to 96.3 decibels. 24-bit audio recordings can capture a dynamic range of up to 144.5 dB. Meanwhile, 32-bit float audio can capture the absolutely ludicrous range of up to 1,528 dB. That’s not only massively beyond the scope of 24-bit audio, but it’s beyond the scale of what even counts as a sound on Earth.

Setting levels on 24-bit systems can be tricky because of the noise floor. To oversimplify, no matter how quiet you make your recording space, there’s always some amount of noise from background objects, or even the electronics you record on. Adding gain to the signal while recording will amplify that noise, as well as hiss and unwanted artefacts, and once it’s baked into the recording, it’s there for good.

32-bit float recordings have more flexibility to make adjustments after the fact (and in some cases, it might even help with low-level noise problems). 

In paranormal research it is essential to have the cleanest audio recording possible as we are trying to filter out sounds that are usually hidden behind others, the cleaner and higher quality the recording the more processing and isolation you can do to it when listening back.

Please note there is a file size issue to consider with 32-bit recordings, though they are a bit overblown. In general, you can expect 32-bit audio to be about 33 percent larger than 24-bit recordings

For capturing quiet sounds with an audio recorder, please also consider the following settings

1. Try to use a low self-noise and highly sensitive microphone to keep its own noise low but that picks up even the quietest sounds well

2. Enabling a low cut (high-pass) filter to eliminate low-frequency background noise or handling vibrations is a matter of choice, sometimes this can eliminate growls or moans so I would prefer to filter out low frequencies after recording.

3. Always use a Lossless File Format: (e.g., WAV) to preserve the original sound quality during recording.  MP3 files are much smaller and have been compressed so they lose some data. WAV files have not been compressed, so they have more data. This means more in terms of file size, but also usually means better quality of audio and more options for editing.

4. A standard sampling rate of 48 kHz is often sufficient for capturing a wide range of frequencies. I actually record at 96 kHz

Zoom has just introduced a new range of 32 bit float handy recorders which will have similar price tags to the older models

Microphones

An omnidirectional microphone is designed to capture sound from all directions equally. Unlike directional microphones that focus on specific sources, an omnidirectional microphone picks up sound from all around its diaphragm. This makes it versatile for capturing a broad range of audio sources in various environments. Omni microphones are commonly used in situations where you want to capture ambient sounds, group conversations, or when the source of the sound is not fixed in one direction. The only drawback with omnidirectional microphones is that if you capture a voice the microphones polar pattern will not have a directional quality and will not hear the sound as well. In my opinion this is the only way to capture sounds from unknown directions

Audio Editing

EQ, which stands for Equalization, is a fundamental tool in sound mixing. It involves adjusting the balance of frequencies within an audio signal. With EQ, you can boost or cut specific frequency ranges to enhance or reduce certain elements of the sound.

There is no scientific evidence supporting the existence of paranormal spirits or any specific frequency at which they might communicate. Claims about spirits communicating at certain frequencies are often associated with pseudoscience or paranormal beliefs. When isolating a EVP or spirit voice I usually increase the typical human voice frequency range. An adult male will have a fundamental frequency from 85 to 155 Hz, and a typical adult female from 165 to 255 Hz. From my own experience, I have found that unidentified voices can sometimes lie outside the above ranges

Voice isolation in audio editing refers to the process of separating a specific voice or vocal element from the rest of the audio content. This is typically done to enhance or isolate a particular voice in a recording. There are various new Voice Isolation applications and plugins using machine learning to remove anything from a click/track that isn't a human voice.

In summary, for EVP recordings, 32bit float will reduce unwanted noise and hiss while providing higher quality recordings

More Reading

https://nofilmschool.com/zoom-32-bit-recorders