Originally Posted by Nikonowski
Is there any one out there that can technically explain why he is experiencing such a big difference (once again in his opinion) with LPCM turned on ?
Thanks once again,
First, as others have stated, he is hearing the DTS 1.5mbps "core" on both PCM and Bitstream. However, that does not mean that what he is hearing is "identical". There are a number of receivers that bypass various "enhancements" when receiving an LPCM signal. If he has a volume compression setting or some ambience setting turned on, that may account for the difference. At least in my opinion, many of the additional processing features that supposedly enhance the sound often sound worse to me than the raw feed. Also, it is possible that his receiver has a flawed decoder that is mishandling the DTS core.
It shouldn't be hard to test: Turn off all enhancements (such as matrixed 7 channel sound, dynamic compression, "concert hall", whatever) on the receiver (including audyssey). Next, level match between the two settings using an SPL meter. Now have him flip back and forth between the two options until he is clear in his head which is which. Now "blind" him (not literally!) and then you switch back and forth randomly between the two (like a, a, b, a, b, b, a, b, a, a, etc.) and have him record which (LPCM or bitstream) he thinks he is hearing. You can't just switch back and forth, but must occasionally "fake" a change.
If the two sound the same when level matched and all additional processing is turned off, then either post-processing or volume account for the differences. If he can reliably tell a difference between the two formats, then one of the decoders is doing something wrong. If he can't, then you've confirmed what many of us believe accounts for many of the differences reported on forums such as these: placebo effect.