I don't have the best hearing anymore but I don't notice any sharpness increase.
Officially it is 48 kHz after encoding but some frontends will resample it back to original 32 kHz…
Less bodied, thinner sound of Opus encoded file becomes audible to me at the end of the phrase: "Penguin Audio pre
sents". The waveform supports this observation (figure 1). The difference stands out more with players that use BASS (https://www.un4seen.com/) library. It reminds me of the effect that your Noise sharpening (https://www.foobar2000.org/components/view/foo_dsp_delta) DSP produces, when some high frequencies are boosted. After upsampling WAV 32 kHz to 48 kHz via SoX DSP and encoding again without any switches, we see (figure 2) the trailing part has “grown” back. However, it is difficult for me to say whether this was influenced by the preliminary upsampling or the fact that Opus now used more bits for encoding (50.9 vs 80.1). As for the evaluation by ear, I feel that the trailing part now sounds as loud as the original, but the character is still a bit crisper.
Figure 1
(https://img.imgdd.com/f210f3.d553f4f5-5443-409d-8528-98dccd72e333.webp)
Figure 2
(https://img.imgdd.com/f210f3.45a725d9-3e07-48d1-885a-f7e923faeb00.webp)
Figures are animated lossless WEBP, 2 frames each with 1.5 seconds delay.