8570w versus 8570w EliteBook Workstation

[DBrunnenmeyer]

I am posting this issue here because the troublesome problem exists on the HP 8570w workstation.

It is desirable here in our workflow applications to employ Audacity to record audio on the same PC as the application playing the music. The Audacity tutorials indicate that the preferred audio host for doing this is Windows WASAPI. Making this selection along with setting the record and playback parameters to "...speakers (loopback) and "...speakers" respectively results in poor fidelity when using the HP 8570w. Performing the same recording tasks on our HP 8470p and HP 8570p computers yields excellent results. This suggests (to me, at least) that the audio system architecture in the 8570w workstation is defective in this respect. My guess is that the feed to the loopback input to Audacity has, for whatever reason, a high-pass filter or algorithm in the loopback path.

A spectral analysis of the recorded audio when using the 8570w for this purpose shows a drastic loss of low-end content, beginning at about 150 Hz and with up to 60-80 dB attenuation below that point. Performing the same task with that 8470p and the 8570p shows only a slight attenuation in the same frequency range, most likely due to the actual audio spectrum of the source file.

We bought the 8570w expecting superior performance but now find that we can't use it for this particular purpose. Otherwise, it appears to be a fine product. Can anyone explain why this problem exists on the EliteBook 8570w?