Sweep Noise, Explained: How the ANC-Mini Cleans Up a Spirit Box Session
A spirit box is noisy by design. The sweep never rests on a station, and between each step there is a burst of white noise. On my P-SB7 that white noise is proprietary and deliberate, because the changing audio is the raw material a response can form in. But the same noise that makes the method work is also the main thing standing between your ear and a clear response. The ANC-Mini is the small device I designed to manage it.
What the ANC-Mini is
The ANC-Mini is an Adjustable Noise Control and Spirit Response Amplifying device. It sits between your spirit box and your speaker and it runs a proprietary software algorithm that dynamically adjusts the audio Hold and Release properties. In plain terms, it holds back the harsh sweep noise and releases the audio a response rides on, so what comes through is easier to hear and easier to decipher. The whole device is controlled with two buttons. That simplicity is intentional. In a dark building at two in the morning, you do not want a menu system.
It works with the P-SB7, P-SB7T, and P-SB11, with the S-Box, and with many other sweep radios that offer a separate audio output.
Watch the demo
Setting it up correctly
Setup takes about a minute, and the volume settings matter more than people expect. Connect the SPOUT audio output of your P-SB7 to the audio input of the ANC-Mini, then run the ANC-Mini output to a speaker like the X1. If you use an S-Box, connect from its earphone output instead. Then set the spirit box volume for the revision you own: on a Rev 4 or earlier P-SB7, the one with the blue display, set the volume to 30. On a Rev 5, the red display, set it between 19 and 21. Get that level right first, then use the two ANC-Mini buttons to dial the noise where you want it.
What noise control does not do
Here is the honest engineering note. The ANC-Mini shapes what your spirit box already captured. It does not add anything, and it should never be used to manufacture a response out of nothing. I share responses in their original, natural form, with no reverb or delay effects, and I hold noise control to the same standard: if a response only exists after aggressive processing, treat it with suspicion. A genuine response gets clearer as the noise comes down. A trick of the ear falls apart.
When to step up to the DAS-ANC-PRO
The ANC-Mini is the compact option. Its bigger sibling, the DAS-ANC-PRO, gives you sweep noise removal adjustable from 0 to 100 percent, a bright OLED display that shows the audio spectrum and raw oscilloscope data in real time, and an amplified speaker with a rotating ring volume control. When you can see the shape of the audio while you listen, you rely less on wishful hearing, and that makes your review more honest. Start with the ANC-Mini. Move up when you want the display.
See the ANC-Mini and the X1-ANC speaker, or browse all Spirit Boxes.
