Here is how I dial in a sub. I do this procedure fairly often and it works very well. You can dial in a pair of subs in less than 10 minutes. It helps to have another person making the adjustments while you listen. We’ll use the sub’s level control and the sub’s low pass filter (frequency) control.
- Play something with good bass content. I use Michael Jackson’s “Thriller” CD, and play Thriller.
- If you have two subs: use the preamp balance control (or disconnect the other channel’s CD input to the preamp) so only one channel is playing.
- Turn the sub’s freq control all the way down.
- Starting with the sub’s volume control all the way down, slowly turn the volume control up until you just hear the sub.
- Slowly turn up the freq control until the bass becomes boomy. The boomy character means the sub frequencies are overlapping the bass from the main speakers. We don’t want this. Turn the freq control down until the boominess is gone.
- Repeat #4, noting the setting before adjusting.
- Repeat #5, noting the setting before adjusting.