Question PC "2.1" setup bass problem

[Loki_TSO]

I have a small "2.1" amp with two speakers and an active subwoofer plugged in it but sometimes the sub just doesn't work...I tried to plug it directly in the center\sub 3.5mm port and with it plugged in the amp with only one 3.5mm jack for the speakers and sub and both have this problem. I was using Equalizer APO to copy the LR channels to the sub but it stopped working (and it wasn't that great).

Is there something I can do to fix this?

 

[punkncat]

Loads of questions.

First, probably a good idea to give us some model number and info for the amp and speakers.
Next, would be helpful to know what the source is.

When you say "active" sub, you mean powered?

Powered speakers are typically going to be wanting line level input which may or may not be variable (volume control). If you are feeding a power signal to the (then) powered amp it could be going into a protection mode (etc.) to prevent damage. Really just speculation until we know what components are being discussed.

 

[Loki_TSO]

The amp is a Fossi Audio BL10C which is plugged in my PC via a red/white to 3.5mm audio jack.
The sub is indeed powered and is plugged in the subwoofer port of the amp, it a Cambridge Audio Minx X200.
As for the speakers, they're small hard wired speakers from Lancaster audio ( they where part of a 5ch kit), the power handling is 100w and the impedance is 8ohm.

 

[punkncat]

Is it this unit?

Fosi Audio BT10A Bluetooth Stereo Amp Review | Audio Science Review (ASR) Forum

It doesn't have a sub level output based on the above. I cannot find other reviews of that same model. It is a cheapo unit wanting 4 ohm speakers and at a $50 price point (based on the above) wouldn't be expecting much other than sound from it to two speakers.