Quick Start Guide

Last Update: 1/4/21

Applications Manual for Sound Recording with iOS

You see the App recognizes the Sonic Presence USB Input Device provided you’ve followed our procedure. Below the

microphone indication is an Audio Gain slider that adjusts the Mic Volume. It’s calibrated from 0 to 100%, which is not

exactly a pro audio standard, but is sufficient as a reference. Our testing showed the best results when the slider was at

50%. You can select the sampling rate of 44.1kHz or 48kHz. The audio word sample size is fixed at 16-bit. You can select

the audio file format. AAC is a compressed file format with a bit rate of 256kbps, while PCM is an uncompressed linear

format. Click on the “checkmark” icon to return to the App’s main screen.

Meter Check and Level Testing

The Audio Gain control is calibrated from 0% to 100%. We measured the actual gain/attenuation in dB with a reference

of 0dB at the center or 50%. As you can see there is a wide range of adjustment. We recommend you stay within plus or

minus 6dB to avoid distortion.

The audio level meter on the Main Screen of this App is quite accurate. Unfortunately, it does not have any calibration

marks to guide you. We set the Audio Gain to 50%, which gave us these dB scale calibration marks. If you keep your peak

audio levels in the yellow, you’ll get very good sound quality.

-24 -18 -12 -6 -3 0dB

We also checked the meter level with a calibrated acoustic sound source. It showed -3.0dB at a Sound Pressure Level (SPL)

of 120dB. That’s loud! We actually calibrate our Sonic Presence mics at this level, so the dynamic range of this App is a

good match.

This table shows the relationship between our signal generator, the meter readings and the analog output level of the

headphone jack. You can see the linearity is really quite excellent, which means that changes in the Output Level accurately

follow changes in the Input Level.

ProMovie

Scale 10% 25% 38% 50% 62% 75% 88% 100%

Gain dB -26 -18 -8 0 +6 +14 +22 +30