Stupid question about HU KDC-9020R (sub/speaker settings)

[dangerous_daveo]

As per topic I've got a Kenwood KDC-9020R, at the time it was a higher end unit, fancy stuff on it, plays MP3s if the prod code doesnt ring any bells.

Anyway, when the unit is in stand-by mode you can select different speaker/sub settings. This basically lets the unit know what speakers you are running and its ment to change the sound, and preset sound settings to suit.

Now the tricky bit. With the sub side of these settings it has...

10inch sub type A

10inch sub type B

10inch sub type C

10inch sub type D

My question being, what the hell is the difference between an A type and a C type etc, if any??? Im fully lost aye.

[dangerous_daveo]

Bump?

[paulr33]

could be wattage or frequency response for the sub

ranging from normal cheapo sub to very good sub with lots of low down response so the headunit has an idea how much bass to bridge to the sub channel for it