Quick Start Guide

Last Update: 1/4/21

Applications Manual for Sound Recording with iOS

Meter Check and Level Test

We made the tests with the “Input Gain” set to the center of the

slider. We recommend this gain setting as a good starting

point. Our acoustic signal generator calibrated to 114dB.SPL

registers “-10” on the meter display. That same source set to

94dB SPL registers -30 on the meters. This confirms the App

responds linearly to a change in level, which means that

changes in the Output Level accurately follow changes in the

Input Level. There is no compression effect due to signal processing.

The meter’s scale markings are calibrated in dB. Our

electrical measurement confirms these meters are 100%

accurate. The red scale is 0dB to -6dB, the yellow -6dB to

-12dB and the green scale is from -12dB down to infinity.

Twisted Wave Level Meters

The “Input Gain” for this App sets the Recording Level. The gain is unity or 0dB when the slider is in the center position.

We’ve calibrated the VR15-USB, so it can record sounds up to 120dBSPL without distortion when the slider is set to the

center position. You can choose to move the slider, cautiously, to increase or decrease the Recording Level. Moving the

slider to the right will increase the level by up to 30dB, while moving it to the left will decrease the level down to -30dB.

We strongly suggest you leave the Input Gain in the center position most of the time. If the sound is extremely loud, a

slight nudge to the left is all that’s needed. Same rule of thumb for softer sounds. A slight nudge to the right is all that’s

needed.

This table shows the detailed test results for this App’s performance.

Twisted Wave Mic Volume

Scale --- -- - center + ++ +++

Gain dB -30 -20 -10 0 +10 +20 +30