so i heard one car audio guy said the best placement for an underseat subwoofer ranks by:

1. front passenger leg area
2. passenger underseat
3. driver underseat


i feel weird la coz all these while i'm using it under driver underseat, while i was asking for recommendation, he said it's best to put at foot well there.

any taiko can guide on this?

Low frequency sounds are typically omnidirectional. So placement is not that important. Placing in the front passaged footwell just means you have a larger area to put a bigger enclosure or bigger subwoofer.