Bi amping question

Hi there,

I have some no-name old speakers which should support bi amping, on the back there is this
 type of terminal
When I remove those connections between bottom and top posts and plug amplifier to bottom posts, only bass is playing. Which is good I suppose. 
But here is the problem, when I plug amp to top posts, speakers play fullrange ?? Shouldn't only mids and highs be playing ?

I assume it is not safe to bi-amp them right now.
What do you think ?


@peterb999 - connect the cables to the top posts and then placing your finger lightly on the bass driver cone check the bass driver for movement (i.e. if the grill can be removed)

Your speakers may be designed such that only the very low end of audio spetrum  is handled by the bass driver. and mid/upper bass frequencies are handled adequately by the other drivers.

If your music only has "mid bass" frequencies it might sound as though the bass driver is still connected.

Hope that helps 

Regards - Steve
These are those speakers. They are 3way.
They definitely play full range when hooked up to upper posts as the bass speaker is moving and low bass are present.

Post removed 
@mental Maybe... So does anybody know if it's safe to bi-amp in this case? I thought upper posts would drive only mids/highs which isn't the case. Curiously lower posts drive only bass section :/
Post removed 
Use a VOM to check the resistance between the two sets of posts.  If they aren't isolated from each other you don't want to try biamping as the two amps will interact.
Post removed 
For future reference, it was possible to biamp these speakers. Posts are wired so that the hidden speaker is connected to one binding post and rest of speakers to second binding post.
So basically williewonka was right.
Thanks all