I am looking forward to testing the Pokit and the Pokit Pro in a car audio application. Many professional installers used oscilloscopes to tune their amplifiers by viewing the waveform and adjusting the amplifiers gain setting accordingly. I would love to see a dedicated audio calibration option.
Typically, a 40Hz or a 1kHz tone is played, and the A/C output from the headunit's RCA connections are measured (typically 2-6v output) to find where distortion/clipping of the output signal occurs. This becomes the maximum volume level for the headunit, and will be the level used when tuning the amplifier.
Next, the meter will be connected to the A/C output of the amplifier itself. Voltages on most consumer amplifiers will be around 30-40v. Larger competition amplifiers could easily exceed 70v. A 40Hz or 1kHz tone would be played from the headunit at the maximum level found in the previous test. The gain control on the amplifier would slowly be increased until distortion or waveform clipping is detected, then lowered to a desired point just before that level. This ensures a clean audio signal at all levels of listening, and protects the vehicles speakers from possible damage due to clipping signals.
Currently, most of the car audio community uses a SMD DD1. That handheld device operates exactly and explained above and has leds that light up for the test. 2 leds are simple detect lights, one labeled 40hz and one labled 1kHz that will light up as soon as the corresponding tone is played (helpful as tuning is typically done with no drivers/speakers connected to the amp). The other led is distortion, which will illuminate as soon as distortion is detected, allowing for a quick tuning solution.
I believe this would be a very handy feature to add in the app. Simply indicating if a signal or a specific frequency is detected, and indicating when distortion is detected.
To make it easier, a drop-down selection for set frequencies will make it simpler to program what waveform to look for. The user can play the selected tone, and the app will already be monitoring the selected frequency for distortion.
Please sign in to leave a comment.