Some amplifiers can have two of their channels "bridged" for almost 4 times the power as one. I don't know if your unknown amplifier can be bridged. I don't know the impedance of your sub-woofer speaker.
There are thousands of adjustable frequency lowpass filter sub-woofer circuits on the internet. Maybe you should also use a highpass filter for the main channels.
The volume control for a sub-woofer amplifier is at the input of the amplifier.
The amplifier is low power, poor quality (Chinese) and poor performance. The power numbers are exaggerated.
Your mid-range and tweeters will blow up. They each need their own crossover circuit.
This Tripath module is already "bridged" and claims 117W at 10% distortion into a bridged 4 ohm load. Since your speakers are 8 ohm, they only claim 35Wpc before distortion begins to get unbearable.
Maybe you could run one sub from each amplifier but you must not connect the speaker lines together.
Sorry for not being conformative and appreciate your advice so far..
But
I Will have the following setup
100w Left output to a tweeter and mid range.
100w Right output to a tweeter and mid range.
100w Output to each subwoofer.
What circuit would i use on the lines and can you supply something for me to follow, Ive found lots of schematics on google but which one as they are all different in there own ways.
Im guessing i would need a Mid and tweeter filter in one circuit and a separate filter for each sub.
A sub-woofer usually does not produce upper bass frequencies that a woofer would produce. You do not have woofers.
Here is a 3-way active crossover with 12dB Butterworth slopes and two 2-way 18dB Linkwitz-Riley slopes: **broken link removed** **broken link removed**