Yes, another stupid question :) AVR's and True HD

As I stated earlier, it's gear dependent. :rolleyes:

Your BRP will not always sound better if it internally decoded the signal, neither will your AVR if you chose that to decode it. It's one or the other depending how you have things hooked up and what avr/brp you're using.

technology moves too damn quickly
seems like my upgrades are already outdated lol

olilugo wrote: »

If you have a BRP and you set it to send PCM, then the BRP DAC is decoding the sound and there is not decoding done by the AVR.

Only true if you use analog outs on the player instead of hdmi for the PCM.

Pycroft wrote: »

Now, the big question is, can I get a better system with preouts that doesn't decode for the same price or better, and if so, would I be losing any quality using the BD player in that way? If so, I'd love to hear recommendations.

Pycroft

Unfortunately, you have to understand how the audio is processed in order to figure out what works best for you. I will try to give you a non-technical answer where I can, but you should try to understand the process to know what trade-offs you are making.

Decoding (uncompressing, unzipping)

There are three lossless formats, uncompressed PCM and TrueHD and DTS-HD Master Audio(MA). All the other alphabet soup out there are lossy formats which simply means that they take an uncompressed PCM master, compress it to make it smaller (like a zip file on a pc) and when the file is uncompressed (decoded), there are parts of it missing that were taken out in the original compression. So a Dolby Digital compression process, for instance, may eliminate certain frequencies that it thinks the listener won't mind losing from the original master.

So for uncompressed PCM (getting rarer as an option these days although Sony and Disney used to use it a lot), there is no 'decoding' necessary in either the AVR or the player. For TrueHD and DTS-HD MA, the player or AVR must 'unzip' the file back into the original PCM (losslessly) to use it. No one has ever listened to a TrueHD or DTS-HD MA track as its compressed form is unusable. It must be uncompressed back into its space hogging PCM form in order for the AVR to process it and send it to the speakers. So people are really listening to the original PCM master with all three formats and this is why all three lossless formats should be equivalent to each other with the quality coming from the original master, not the zip/unzip process. And that is why uncompressing the file (decoding, unzipping whatever you want to call it) is less relevant to sound quality than the digital/analog conversion process. And since you get the same PCM with either a player or AVR decode, it shouldn't matter where the decoding process takes place. Although, as I already noted, the LFE 10db boost is not handled consistently across all AVRs on the PCM input. So if you aren't willing to go through the extra technical effort to make sure your system is calibrated and setup properly for this boost on the PCM input, then you are better off just letting the AVR uncompress (decode, unzip) the lossless track as it always knows to add the boost back in. However, you will still run into trouble with the uncompressed PCM tracks (as these are always transmitted as multichannel PCM).

Digital/Analog Conversion

This is where much of the quality in digital processing comes from. And this really predates any talk of lossless compression/uncompression/blu-ray etc. It comes from the simple fact that although we process audio largely in the digital world these days, speakers are still completely analog components. So as ironic as it may sound, after all the digital voodoo that goes on under the hood of a modern AVR or pre-amp, we end up listening to a purely analog signal sent to the amplifier stage and over the speaker wires to our speakers.

So at some point, the digital 1s and 0s have to be converted back into analog and sent to the amplification stage and out to the speakers. There is no 100% way (lossless) to go from digital to analog and there will always be some guesswork involved. That's why the DAC (digital/analog converter) chips will add their own color to the sound.

When you decode (unzip) lossless formats in the player and use the analog outs to send the results to the AVR or pre-amp, the player is converting the digital information to analog early in the process and using its own internal DAC chips after the decoding (unzipping) process, dumping the results of this conversion to the AVR or pre-amp. This is the only situation where the DAC chips of the player are relevant.

When you use the player to decode (unzip) and send multichannel PCM over HDMI OR decode (unzip) the bitstream on the AVR side, it is all digital. So the AVR must use its own DAC chips to convert the digital information before sending an analog signal to the amplification stage and on to the speakers.

Short Answer

If you don't want to worry about if the AVR is applying the 10db LFE boost properly to the PCM input, then use bitstreaming and decode (unzip) in the AVR. But you will still have to worry about the LFE boost when listening to the uncompressed PCM track on some blu-rays. And it is entirely possible to get great lossless audio letting the player decode (unzip) lossless tracks and sending the result over either hdmi or analog outs to the AVR with no discernable loss in audio quality.

If using the analog outs of the player, all the old arguments about player vs. AVR DAC quality still apply since you will be using the player DACs to do the initial digital to analog conversion instead of the AVR's.

cheddar wrote: »

I guess the question becomes why would you need to adjust the recorded level and boost it later if there were no bottlenecking in the electronics. It's what I read about the limitations of the connection with the additional LFE range.

The +10dB boost is actually a holdover from 70mm magnetic film where mixers had limited headroom on the analog tracks. It was a limitation of that medium. The +10dB boost was carried over to digital because mixers were already accustomed to mixing LFE at -10dB.

Here's some good reading on the subject.

I stand corrected. I meant the decoded chip instead of digital to analog(DAC) chip.
sorry.

kuntasensei wrote: »

I wasn't saying that the limitations of the ICs wasn't an existing issue... Just saying that your original statement that Blu-ray and DVD have the LFE track recorded at -10dB to prevent overloading the connections is not correct. They have the LFE channel recorded at -10dB because the original theatrical mix has the LFE channel recorded at that level, which is a holdover from analog multichannel on film that carried over to the digital formats. The specs exist to suit the format, not vice-versa.

If you want to point out the historical significance of the original recording methods, fine. The fact remains that they have no choice but to record the LFE at -10db. Even if they wanted to change the standard for blu-ray, they couldn't unless they forced an upgrade to a new hardware standard (and bandwidth is always at a premium anyways, so it may just be the case that it's more economical to keep the status quo for the .1 surround channel that filters out the higher noise levels caused by the boost anyways) because as the article clearly states, 3x the available bandwidth would overload the rated specs of the existing connections, which is what I stated. I made no reference to the historical root cause of the problem. Only the current hardware limitations which would prevent full strength LFE channels from being transmitted. For my statement to be incorrect, the studios would have to have a choice to record at the higher level without overloading the current connections and simply choose not to do it because they are used to the old routines. And studios remix sound for blu-rays all the time. Certainly, the 7.1 lossless tracks of the classic Star Trek TV blu-rays never existed before the blu-rays were produced. Even these new lossless tracks can only have a -10db LFE track because the hardware would be overloaded by a 3x higher level signal. Which is basically what I said in my initial statement.

Mike LoManaco wrote: »

Have you read anything about the ongoing rage and debate regarding the fact that soundtracks shouldn't sound ANY different based on where they're decoded, in a player or in a surround device, such as a processor or AVR? These people SWEAR by this notion -- but my ears are telling me that something is indeed different when the TrueHD tracks are being decoded by the player rather than the receiver because they don't sound nearly as dramatic in output.

Mike LoManaco wrote: »

In my particular case, my Panasonic Blu-ray deck has been plagued by a known "LFE bug" which means the PLAYER does not send out the correct amount of bass information over HDMI when the PLAYER is doing the internal decoding to PCM. It's a known problem with the first-generation Panasonic BD players, specifically my DMP-BD10A.

Then maybe try not to weigh into a debate with broad generalized statements when you wouldn't expect to hear equal audio (player vs. AVR decoding) since your equipment is malfunctioning and you've never heard properly processed player decoded lossless audio...just a thought.

Mike LoManaco wrote: »

Not called for -- and aside from the LFE issue with the player, I am hearing lossless audio.

You asked about the LFE bug, claiming you were not certain what I meant by that, and I was merely explaining it.

I said you've never heard properly processed player decoded lossless audio. I would think as someone who prides himself on writing audio and video critiques of movies, that you would want to actually hear player decoded lossless produced per proper specs before you suggest generalized conclusions about it being inferior to AVR decoded lossless and even standard dolby digital. If you don't see a problem with generalizing from one faulty player to suggest that player decoded lossless is inferior to AVR decoded audio, then carry on...make any claims you want. But I would recommend that you upgrade your player at some point so that you can eventually write a critique based on properly processed lossless audio whether decoded in the player or AVR. It really is far better than the undynamic, unpunchy sound you often describe and is a joy to listen to.

Mike LoManaco wrote: »

I know the player has an LFE bug, and I was sharing my experiences of this in the thread, but attempting to help the OP. It DOESN'T mean I don't know anything in terms of being able to review a disc for print or discussion. I'm unsubscribing from this thread now, being that my thoughts have been relayed on it -- I hope the OP gets his answers in a coherent fashion.

I never said anything one way or the other about the quality of your reviews other than to point out that with an admitted -5db problem on the LFE and what I think might be a -10db problem if you haven't configured your system properly to boost the LFE PCM by the required amount, you will get the exact results you complain about, a lack of punch and dynamics on player decoded tracks vs. AVR decoded. And that any general conclusions you draw from your faulty player about lossless audio would be premature at best.

In direct reference to this thread, since the OP does not own your faulty player, the multiple posts that you've given which suggest to him that in general, player decoded lossless is inferior to AVR decoded lossless (both of which you seem to have not heard properly processed, just the lossy bitstreamed tracks), brings confusion to the discussion when you haven't even proven that his player suffers from the same LFE bug. Those of us who have actually heard player decoded lossless without your LFE bug might know a little better about how it can sound than someone who hasn't. That's all I am saying. No more no less.