I have a pair of Spendor SP/71's and by design they slope backwards. A few days ago I decided to place some wooden blocks under the rear spikes thus raising the speakers to a level position. Well the sound difference is amazing! The sound is now directly in my face and sounds more direct and impacting. Of course this maybe a 'new to the ears' experience so may not be the best in the long term but as it stands it seems to be a massive improvement.
Just what were Spendor (or any other manufacturer) trying to achieve by angling speakers back so they fire over your head?