The aspects to consider for the audio differences between using a Panasonic BD30 or BD50 versus a PS3 with your setup are:
1. Due to hardware limitations the PS3 cannot bitstream out the advanced lossless Dolby and DTS audio formats.
2. However the PS3 can internally decode the lossless Dolby audio (Dolby TrueHD) and output it to your AV Receiver via Linear PCM over the HDMI. Support for internal decoding of the DTS lossless audio (DTS HD-MA) is expected to be added via a firmware update to the PS3 in a few months. Thus with the PS3 your AV Receiver's decoding for the advanced audio formats would not be used as the decoding would have already have been performed withing the PS3.
3. In contrast the BD30 only bitstreams these advanced audio formats to your AV receiver where the decoding is performed. The BD50 allows either option, decoding within the BD player and output via LPCM, or bitream output.
4. Now the bottom line on which sounds better, having the decoding done within the BD player or within the AVR. If the docoder is correctly implemented (either within the BD player or the receiver) exactly the same PCM bit pattern will be produced. Therefore any difference in audio quality should not be a result of any difference in the decoded bit string. Rather it comes down primarily to a factor that can make small differences in the audio. Specifially, it is generally accepted that jitter (small timing errors in the spacing between digital bits) in the bit string being fed into the receiver's Digital-to-Analog Converter (i.e., DAC) can, if large enough, impact the audio quality of the analog output of the DAC. In the case of encoded audio (Dolby or DTS) being sent via bitstream to your receiver the jitter introduced over the HDMI between the BD player and the receiver is not as important since the receiver must have an internal decoder with its own timing source that will generate the bit positions of the decoded digital bit stream. Thus in this case the small timing errors between the BD player and the receiver won't directly result in equalivant jitter on the data stream going to the receiver's DAC. Now considering the alternative case where the Dolby and DTS decoding is being done within the BD player, any jitter introduced on the bit stream going over the HDMI interface to the AV receiver will be directly passed onto the input of the receiver's DAC unless the AV receiver includes internal data buffering and re-clocking of the data stream. Although such a de-jitter feature would be quite easy to implement, I'm not aware if any manufacturers that actually do it. Thus in theory passing an undecoded bit stream to the AV receiver from the BD player could result in slightly better sound quality. However, with your specific setup you may, or may not, be able to actually hear a difference.
Blog + Reviews + Articles: projectorreviews.com