Demo speakers are just used speakers.
Some warranties only cover from the date sent to the dealer. Some do cover from the date the customer buys them.
Check to see just how old they really are.
The dealer certainly knows the exact date they bought them.
If they are waffling on the date. be wary.
Make certain the warranty starts the day YOU buy them. not the date the dealer bought them.
Standard used is 50% of new, with varying factors. Are they 'desirable' speakers lots of folks want? Are they cold, nobody wants them?
Then how old. Two years or more is too old and price should drop.
Are they a current model? or a discontinued model?
For five year old speakers where the warranty is from time dealer took delivery, and the speaker is a discontinued model.. 50% tops is a fair price. With damage,, ot would drop to BELOW 50%
For speakers which are hot and folks love them, the current model, and only a year old, plus the warranty starts the day YOU buy them.. 30% off is fine. With a noticable ding.. 35% off.
Since ANYONE can buy brand new current model speakers for 15% to 20% off.. just remember that...