I was watching some random car audio vids on YouTube when I saw the CT Sounds Universal Bass Knob (UBK); it functions like any other “universal bass knob” in that you install it in between the signal source and the amplifier and you can use the rotary knob to adjust the signal strength, which in turn controls the strength of the bass. However what caught my eye with this one is that it has a built-in voltmeter and an optional on/off switch – all in a small little unit. and I ordered one from CT Sounds and it actually took 7 days to show up… which didn’t make sense considering it was shipped from Inglewood, CA which is about a 40 minute drive from my house.
For my system, I installed the UBK in between the JL Audio TWK-88 DSP processor and my Alpine PDX-V9 amplifier on the subwoofer channel. Since this is the amplifier that pulls the most power out of the system, I connected the voltmeter to the amp’s power lead to monitor the battery voltage.
The optional on/off switch works by simply pushing the rotary knob in/out, and it’s supposed to be to control the remote circuit to turn the amplifier on/off. However it’s a simply switch so it can be used as a toggle for anything, though right now I didn’t connect it to anything yet. Pushing the knob also lets me turn the voltmeter display on/off, which might be useful since the display is pretty bright:
UPDATE 04.29.19: CT Sounds control knob removed.