Can I connect into an amplifier, out from a speaker selector?

I'm trying to wire 4 outdoor speakers (Yamaha NSAW150), but they don't seem to be getting enough power. Is is possible to run speaker wire out of a speaker selector, into an amp, then to the speakers?

Here's the scenario... I have a Technics amp/receiver. I have a Left and Right speaker wire(s) coming out of the 'B Speaker' into the Left and Right speaker connections of a (Omage AT4V) speaker selector. From the speaker selector, I am running 4 speaker wires to 4 speakers (not pairs).

I have to really crank the volume of the amp and speaker selector to get sufficient sound out of the outdoor speakers.

Does the distance to the speaker affect the wattage/power that reaches them?

Specs on items:

- Amp: 100W per channel, 8 ohms
- Speakers: 120W (max), 6 ohms
- Speaker Selector: Individual volume control (x4), impedance correction, 100W max per channel
- Wire: 14 gauge landscaping wire

When I run the speakers directly to the amp, they seem under-powered. When I bridge(?) the speaker wires (R+ and L-), which I think gives me 200W(?), the power/volume seems perfect. I try doing this to the speaker selector, and it seems to limit (to 100W) the power coming in.

Any suggestions would help.

Thanks!

Corey