A good resource is seatguru.com. It shows the good and bad seats on
most airlines and plane configurations.

It doesn't say anything about entertainment boxes on Singaport 747s
though.

For those making fun of the question, I'll recall a nasty trip from
SFO to Heathrow over a decade ago on Virgin Atlantic, with their then
novel personal entertainment systems. The electronics box took up
most of the room under the seat in front of me, cramping legroom.

Because of the limited legroom, they decreed our carry-on too large,
and we had to repack on the jetway into my daypack. With the added
contents, the agent then decreed the daypack had become too large. I
must have given him quite a look, because he hastily backed down.
However, my wife's tissues didn't make it into my daypack, and the
plane didn't have any on board. And she had a cold. It was a
memorable flight.

Anyway, underseat electronic boxes are no joke.

I didn't think that happened any more.

"April 2007" wrote:

I understand Singapore Airline's 747 flying between SFO and Hong Kong has
entertainment boxes under seats. Can anyone confirm exact box locations so
that we can avoid it. Thank you.