T-Pad versus L-Pad

[Baltar]

helo,
i'm asking for a friend who wants attenuation.
i use a Visaton 100 Watt L-Pad for my 8Ohm Cab and recommended it
to him.
actually he confronted me with a T-Pad requirement and i have no clue
about the practical difference. I found out the schematics, but what's
the deal?
cheers, Martin