Negative part of Line level audio waveform clamped

Question

Im trying to record output from an old synth chip (YM3812). The output waveform is centered around 2.5V with peaks at approx. 2.5 +- 1.5V. I can easily connect a pc speaker with a TSSR cable to hear the sound. I connected 2.5V to GND and the audio signal to either the left, the right or both audio channels.

My problem: If I try to record the signal with a PC line input, the signal is clamped at 2.5V. Every part of the waveform that is "negative" relative to GND is removed.

Do you know, why my speaker could handle the negative voltages, while the line input just clipped? Should I connect 0V to GND instead of 2.5V?

Edit: This is the relevant part of my circuit:

^{simulate this circuit – Schematic created using CircuitLab}

Answer 1

Should I connect 0V to GND instead of 2.5V?

Yes, of course. Otherwise you risk a dead short from your 2.5 V source to 0 V if there is a ground return path anywhere in your system.

^{simulate this circuit – Schematic created using CircuitLab}

Figure 1. The audio signal can be decoupled from the DC with the addition of a series capacitor. The capacitor blocks DC whilst allowing audio to pass through. A 10 µF capacitor should do the trick. Watch polarity.