Guys I need your inputs.

Recently my friend gave me his speakers... he said he found it on storage area and took it home.

Now to cut the story short.. the speakers are from a Pioneer Home theatre 5.1 package. Only the 2 tall speakers are with me and I tried to rewire it to a 3.5mm plugged into my headset at my phone. It is working however the output sound volume is low even maxed out from the source.

Can I use this with other home theatre?
Any other suggestions on how can I make use of it?

Model: Pioneer S-DV2T
4ohms, max 100w

Sir may I know what you mean with old and proprietary?

If I have a similar 5.1 pioneer home theatre htz121, can I swap out the speakers with these?