TAS2505EVM: Speaker output waveform

Part Number: TAS2505EVM
Other Parts Discussed in Thread: TAS2505

Tool/software:

The speaker output waveform was output using the evaluation board. The resulting speaker output waveform was a square wave.

Regardless of the volume, the amplitude voltage was ΔV = 9.5V. Isn't this waveform abnormal?

As I understand it, it is a sine wave, as in the sample waveform below, and the amplitude voltage changes depending on the volume.

TAS2505EVM wave↓

DAC 24db

Vol=-0db

yello : spk+

blue:spk - 

red : blue - yellow

TAS2505EVM wave↓

DAC =24db Vol=-10db

Sample(TDA2822 BTL output) wave↓

yellow : spk+

blue:spk - 

red : blue - yellow