How did you get from the sound card to the mach amps? Im assuming you soldered rca inputs into the input side of the mach amp?
My '01 Mustang has the Mach 460 system and to drive the top 4 speakers, I have to run the signal from my sound card through an amp and then it goes through the Mach amps. The bottoms work just find driven from the sound card output (through low pass filter). If I try to drive the signal directly from the sound card to the tops, I hear nothing. However, when I a 200W amp for the tops, the volume is on pretty much 1% and if I turn the nob for a higher gain, it drives the top speakers way too loud. So I was curious if there was another option besides using an amp to drive the speakers? Would a more powerful sound card do the trick? Or something else?
I got a Metra harness that connects to the 4 tops speaker wires. Now that I think about it, the Mach 460 radio was probably the "amplifier" for the tops and the speaker wire goes directly to the speakers. I never actually touch the Mach amps. So from my sounds card I split the RCA for tops and bottoms then the tops RCA goes to the 200W amp then the 2 channel speaker wire goes to the Metra Harness then to the speakers. It just doesn't require a 200W amplifier and I was looking to free up space in my trunk with the computer case and the amplifier unit. I thought maybe a more powerful sound card could drive the top speakers which are just tweeters.