DSP/Decoding logic differences?

[lbcheng]

Just upgraded to an HK AVR635 and am extremely happy but hoped to get some help understanding some of the capabilities of my system that I didn't find off the FAQs and sticky threads here. I posted some of these questions initially to the receiver board before realizing there was a newbie board so apologize if you may have seen some of these before.

The sound difference compared to my HTIB Aiwa receiver was immediately clear -- most of all in music choices I was familiar with. Amazing, and yes, I know that I could have probably gotten the same boost in quality even at the entry-level decent receivers, but very appreciated. Watching a movie, however, was a little less impressive. As this is my first decent receiver, I was hoping to get some help from you all on basic settings and choices to make sure I'm not bottlenecking anything in my system.


1. What are the differences between the different modes: Dolby Digital, Dolby Digital EX, Dolby DTS 5.1, 6.1 DTS-ES Discrete, DTS-ES Matrix, Dolby Pro Logic II, Dolby Pro Logic IIx, DTS Neo:6, Cinema 6.1/5.1, and Music 6.1/5.1), and finally, HK's own Logic 7 (Cinema, Music, and Enhance).
There is a single sheet describing each of these permutations, but what I'm really looking for is your own subjective descriptions of what are the top few for music and top few for HT to test out on my own ears. I am running 5 speakers plus sub.

2. Is there any advantage to running my single video input (DVD) through the receiver instead of directly to my TV? The DVD has component outs but the TV does not (only S-Video), so I assumed that I should keep the direct DVD-TV hookup.

3. Is there any advantage to using the 48khz to 96khz upsampling setting? According to the manual, "the AVR635 allows you to upsample the incoming 48khz signals to 96khz for added resolution." I didn't hear a difference, but wasn't sure if I was either in the wrong decoding mode or need special audio material.

4. Any reason to set up my rears as "Small" speakers vs. "Large"? I think that setting them as Large will push more of the frequency to them, but am not sure if that is a good thing for HT.

5. My audio is currently coming in from a CD jukebox through RCA stereo plugs. The unit does not have an optical/digital out -- would there be significant enough improvement to justify looking for a new unit just to get the digital out?

6. Interconnects: The HK manual recommends 16 gauge or lower on everything. I am running 18 gauge about 15-20' to the surrounds and don't think I'm likely to change those. I would like to hear whether recommendations on whether I need 14, or if 16 or 18 is okay for the mains and center (all 5' or less). Does brand matter for the same gauge? (My wife bought a big roll of 20gauge Monster cable that I don't know what to do with now)

7. Last: I'm not a big gamer, but wonder if there is anything that will allow me to play a game on my laptop in the living room with audio coming through the new setup. A wireless solution is what I'm looking for, as opposed to 10' RCA cables splitting off of my headphone jack.

Thanks in advance for any thoughts -- I would have procrastinated forever had I not found this board and been encouraged by your advice.

 

[MDS]

Congratulations on the major upgrade. Those are all good questions and usually result in very long threads, but I'll give you the quick abridged version to get things started.

1. What are the differences between the different modes: Dolby Digital, Dolby Digital EX, Dolby DTS 5.1, 6.1 DTS-ES Discrete, DTS-ES Matrix, Dolby Pro Logic II, Dolby Pro Logic IIx, DTS Neo:6, Cinema 6.1/5.1, and Music 6.1/5.1), and finally, HK's own Logic 7 (Cinema, Music, and Enhance).
There is a single sheet describing each of these permutations, but what I'm really looking for is your own subjective descriptions of what are the top few for music and top few for HT to test out on my own ears. I am running 5 speakers plus sub.

- Dolby Digital and DTS are lossy compression formats and are the formats found on DVD. They are 'discrete' formats - meaning each channel is separate and distinct from the others. Dolby Digital EX is a 6.1 format, but the 6th channel is not discrete (it is matrixed into the surround channels and extracted during decoding). DTS-ES Discrete and Matrix are also 6.1 formats, with the discrete flavor being discrete and the matrix version being matrixed like DD-EX.
- ProLogic IIx and DTS:Neo6 are 'matrix decoders'. They work on 2 channel analog or digital sources and turn it into 5.1 or more channels. You could use PLIIx to turn analog signals into 5.1, 6.1, or 7.1. PLIIx will also turn DD 2.0 or DD 5.1 into 6.1 or 7.1. Neo:6 only works on 2 channel analog or DTS signals.
- Cinema and Logic7 are also matrix decoders. Logic7 is HK/Lexicon's proprietary matrix decoder.

Which to choose? It's all personal preference. If the disc has DD or DTS, usually you just want to use the native decoder for that format, but you can use one of the matrix decoders if you want to output more channels than are present on the disc; ie use PLIIx to turn DD 5.1 into 7.1.

2. Is there any advantage to running my single video input (DVD) through the receiver instead of directly to my TV? The DVD has component outs but the TV does not (only S-Video), so I assumed that I should keep the direct DVD-TV hookup.

The advantage of running everything through the receiver is ease of switching. The receiver will switch audio and video at the same time so you don't have to switch inputs on the tv as well. If the tv does not have component video inputs then you have no choice but to use the direct connection from dvd to tv if you want to use component video.

3. Is there any advantage to using the 48khz to 96khz upsampling setting? According to the manual, "the AVR635 allows you to upsample the incoming 48khz signals to 96khz for added resolution." I didn't hear a difference, but wasn't sure if I was either in the wrong decoding mode or need special audio material.

Generally there will be no difference, especially since 96 kHz is not a direct multiple of 48 kHz. Upsampling is 'interpolation'; ie the processor adds additional samples to increase the sampling rate. Search the forums for 'nyquist' for a detailed explanation.

4. Any reason to set up my rears as "Small" speakers vs. "Large"? I think that setting them as Large will push more of the frequency to them, but am not sure if that is a good thing for HT.

Yes. Unless the surround speakers are truly full range (can go as low as 20 Hz) you want them set to Small so that the receiver sends the bass to the subwoofer and not those speakers. All speakers Small, Sub=Yes, and an appropriate xover frequency (start at 80 Hz and tweak from there) is the best overall setting. Search for 'bass management'.

5. My audio is currently coming in from a CD jukebox through RCA stereo plugs. The unit does not have an optical/digital out -- would there be significant enough improvement to justify looking for a new unit just to get the digital out?

You will be getting a 2 channel analog signal to the receiver and could use one of the matrix decoders to turn it into 5.1 or greater. If you were to buy a CD player with digital outs, the receiver would then get a 2 channel PCM (digital) signal and will do the digital to analog conversion. If the receiver has better DACS than the player (usually the case) then a digital connection would be preferred.

6. Interconnects: The HK manual recommends 16 gauge or lower on everything. I am running 18 gauge about 15-20' to the surrounds and don't think I'm likely to change those. I would like to hear whether recommendations on whether I need 14, or if 16 or 18 is okay for the mains and center (all 5' or less). Does brand matter for the same gauge? (My wife bought a big roll of 20gauge Monster cable that I don't know what to do with now)

The only thing that really matters for speaker wire is that you use the correct gauge for the length of the run. At 15-20', 18 gauge would be ok, but 16 or lower will reduce the losses a bit. rogerrussell.com (ex McIntosh engineer) has a nice table with gauge recommendations based on length.

Whether you will really be able to hear a difference between 18 and 16 gauge at such a short length is debatable, but for peace of mind, I would opt for 16 or 14 - anything lower than that is pure overkill.

7. Last: I'm not a big gamer, but wonder if there is anything that will allow me to play a game on my laptop in the living room with audio coming through the new setup. A wireless solution is what I'm looking for, as opposed to 10' RCA cables splitting off of my headphone jack.

There are many devices available that connect to both your home network and stereo (Squeezebox2 is the best, IMO) and many of them do 802.11 b/g wireless. If you don't have a home network, but the laptop has a wireless card, you may be able to set it up in 'ad-hoc' mode and connect directly to the media streaming device.

Thanks in advance for any thoughts -- I would have procrastinated forever had I not found this board and been encouraged by your advice.[/QUOTE]

 

[tbewick]

"3. Is there any advantage to using the 48khz to 96khz upsampling setting? According to the manual, "the AVR635 allows you to upsample the incoming 48khz signals to 96khz for added resolution.""

I'm surprised that the Harman/Kardon manual would give such misleading information. You can't generate more resolution by upsampling. Quite honestly, I don't know what the point of upsampling is. It's probably a marketing gimmick. I read a Dolby paper a while back on multichannel music mixing which essentially dismissed upsampling:

"...because a number of 44.1-kHz and 48-kHz sampled digital masters currently exist, it is tempting to zero pad odd samples and integer upsample to be able to claim 88.2-kHz/176.4-kHz or 96-kHz/192-kHz output, respectively. Because the resultant audio stream does not contain additional audio data and is not of higher quality then the original, it is recommended that the music simply be released in its original sample rate (fs) and bit depth."

As for interconnects, I think they usually get more attention than they warrant. Use good quality shielded cable for video and audio connections. As long as you use thick enough speaker cable, you shouldn't have any problems. Room acoustics are surely going to more important than the differences between speaker cable brands. At least acoustical differences are objectively measurable.

 

[lbcheng]

Thanks for the point-by-point help guys! May I ask you to clear up a few points?

Congratulations on the major upgrade. Those are all good questions and usually result in very long threads, but I'll give you the quick abridged version to get things started.

- Dolby Digital and DTS are lossy compression formats and are the formats found on DVD. They are 'discrete' formats - meaning each channel is separate and distinct from the others. Dolby Digital EX is a 6.1 format, but the 6th channel is not discrete (it is matrixed into the surround channels and extracted during decoding). DTS-ES Discrete and Matrix are also 6.1 formats, with the discrete flavor being discrete and the matrix version being matrixed like DD-EX.

I am not even given the option of selecting DTS -- I'm guessing that's because I only have the 5 discrete channels set up. Is that correct?

- ProLogic IIx and DTS:Neo6 are 'matrix decoders'. They work on 2 channel analog or digital sources and turn it into 5.1 or more channels. You could use PLIIx to turn analog signals into 5.1, 6.1, or 7.1. PLIIx will also turn DD 2.0 or DD 5.1 into 6.1 or 7.1. Neo:6 only works on 2 channel analog or DTS signals.

Hmm...played around with these two today on music (PLIIx Music vs. Neo:6 Music) and could not hear a significant difference. Do you prefer one over the other? Does either have a certain characteristic -- ie. decodes and creates a wider soundstage or puts more out to the surrounds, etc?

For movies, I am still not sure what are the few to compare with my 5.1 system. There are so many different variables, that I'd like to start with a few sounds processing options first, then gradually move out to other things like cross-over points, surround delays, etc.

Generally there will be no difference, especially since 96 kHz is not a direct multiple of 48 kHz. Upsampling is 'interpolation'; ie the processor adds additional samples to increase the sampling rate. Search the forums for 'nyquist' for a detailed explanation.

Thanks to you and tbewick, I think this is a dead subject/feature.

You will be getting a 2 channel analog signal to the receiver and could use one of the matrix decoders to turn it into 5.1 or greater. If you were to buy a CD player with digital outs, the receiver would then get a 2 channel PCM (digital) signal and will do the digital to analog conversion. If the receiver has better DACS than the player (usually the case) then a digital connection would be preferred.

Struggling to understand here. So, if I had digital out from an audio source, why would the receiver still do a DAC? Isn't the whole idea to be able to use the source encoding without having to "make it up" through one of the decoders? Would not the driving question be -- if I have significant material that has multiple channel encoding, then I might want to use a digital out connection to preserve that encoding instead of forcing it into 2-channel analog and then having the receiver's decoder guess at replicating it. If, on the other hand, most of my music is standard 2-channel stereo recordings, then I might as well stay with the analog RCA connections, unless digital preserves the signal fidelity better.

There are many devices available that connect to both your home network and stereo (Squeezebox2 is the best, IMO) and many of them do 802.11 b/g wireless. If you don't have a home network, but the laptop has a wireless card, you may be able to set it up in 'ad-hoc' mode and connect directly to the media streaming device.

My next step is to get a media streamer, and I have seen a lot of the options, including the squeezebox and the Roka mediabridge (pretty sexy looking). However, those are more for media, and not really a direct out. I want basically to be able to run any sounds from my PC (from applications, and not necessarily just media) through my receiver. Wouldn't I need some sort of more "instantaneous" direct link such as some proprietary 900mhz or 2.4ghz connection? Or does Squeezebox really allow this? Would I lose much by using a Y-cable from my headphone jack on my laptop to say 15' RCA cables directly into the receiver input? Would I end up losing any encoding by sending the signal out through my headphone jack in the first place as opposed to buying and setting up an external sound card (which I don't want to do unless there's a huge difference in sound).

 

[lbcheng]

The only thing that really matters for speaker wire is that you use the correct gauge for the length of the run. At 15-20', 18 gauge would be ok, but 16 or lower will reduce the losses a bit. rogerrussell.com (ex McIntosh engineer) has a nice table with gauge recommendations based on length.

PS. roger-russell.com is the website to go to. i spent awhile over at rogerrussell.com, an amateur real estate site, wondering if the speaker wire gauge table was hidden somewhere there

 

[MDS]

I am not even given the option of selecting DTS -- I'm guessing that's because I only have the 5 discrete channels set up. Is that correct?

DTS has to be selected from the DVD disc's menu, but not all DVDs have DTS tracks because DTS is actually an optional format for DVD. As long as the receiver is set to 'auto', it should automatically detect a DTS signal and use the DTS decoder. You have to be using optical or coaxial digital cables and have the dvd player set to output 'bitstream' (in the player's menu, not the disc's menu).

Hmm...played around with these two today on music (PLIIx Music vs. Neo:6 Music) and could not hear a significant difference. Do you prefer one over the other?

There are subtle differences in the matrix decoders. I personally prefer PLII Music because it has adjustable parameters for Center Width, Dimension, and Panorama. PLII Movie mode emphasises the center channel and is not user adjustable. I think Neo:6 also has an adjustable center width type control, but I never use it so don't have much experience with it.

Struggling to understand here. So, if I had digital out from an audio source, why would the receiver still do a DAC? Isn't the whole idea to be able to use the source encoding without having to "make it up" through one of the decoders? Would not the driving question be -- if I have significant material that has multiple channel encoding, then I might want to use a digital out connection to preserve that encoding instead of forcing it into 2-channel analog and then having the receiver's decoder guess at replicating it. If, on the other hand, most of my music is standard 2-channel stereo recordings, then I might as well stay with the analog RCA connections, unless digital preserves the signal fidelity better.

The receiver amplifies analog signals, so it must do d/a on the digital signal to turn it into analog so it can amplify it. The d/a has to occur in either the player or the receiver.

If you use analog cables from the player to the receiver (dvd player set to output 'pcm' instead of 'bitstream'), the player will decode the 5.1 DD/DTS signal and downmix it to 2 channel analog. The receiver can then use a matrix decoder to turn those 2 analog channels into 5.1 or whatever and amplify it.

If you use a digital connection (optical or coaxial - doesn't matter) and the player is set to output 'bitstream', the player will simply transport the bits to the receiver and the receiver will do the decoding and conversion to analog, then amplify it. For 2 channel recordings on a CD (which is digital - PCM), then the only issue is whether the receiver or player does a better job of d/a. Usually the receiver will be 'better', but it will be difficult to really detect any difference. However, if the player does have a digital out, then the same 'bitstream' setting will work for DD/DTS/PCM and all the decoding and d/a will occur at the receiver. As long as the receiver is set to 'auto' it will identify the signal as DD or DTS or PCM and use the appropriate decoder.

Would I lose much by using a Y-cable from my headphone jack on my laptop to say 15' RCA cables directly into the receiver input? Would I end up losing any encoding by sending the signal out through my headphone jack in the first place as opposed to buying and setting up an external sound card (which I don't want to do unless there's a huge difference in sound).

Radio Shack and others sell cables with a 1/8" mini plug on one end and 2 RCA plugs on the other end. You can use that for a direct connection to the receiver. Use the line-out of the laptop soundcard instead of headphone if it is available. It will be the same deal as using analog cables from a dvd player - the soundcard (or drivers) will convert any digital format (CD, MP3, WAV, etc) to analog and the receiver will get that analog signal. You can then use one of the matrix decoders to turn it into 5.1 if you wish.

Sorry about the roger-russell.com misspelling. I just typed it in from memory without verifying it.

 

[mtrycrafts]

PS. roger-russell.com is the website to go to. i spent awhile over at rogerrussell.com, an amateur real estate site, wondering if the speaker wire gauge table was hidden somewhere there

Wrong website. Try this link:

http://www.roger-russell.com/

 

[tbewick]

I'd recommend Dolby Pro-Logic IIx Cinema for films/TV. This seems to make better use of the centre channel than DTS Neo:6 Cinema. It is also likely that Dolby Stereo/Surround encoded films/TV programmes were encoded for playback using the Dolby Pro-Logic/PL II/PL IIx decoder. After all, it is the Dolby logo you see on screen.

On my Denon receiver, I found that Denon's own Matrix surround setting provided a nice sense of expansion for music. I wasn't so keen on the Dolby/DTS Music surround settings.