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First of all let me state that I don't consider myself a guru of anything and/or an expert in Home Theater, but I do have long years of experience with Home Theaters. Both as a user and also as a professional dealing in Home Theater equipment/setups. My involvement with Home Theaters goes back to 1986, when I bought my first Pioneer Stereo Receiver and HI Fi stereo VCR, at the time I was living in the US which made upgrading a lot simpler and cheaper compared to now when I live in India. Since then I have gradually updated my system with the newer technologies. I bought my first Laser Disc player and Dolby Surround Receiver in 1989, which I upgraded to a Dolby Pro Logic Receiver in 1990. I bought a Dolby Digital Receiver almost within the first few months of its appearance in the market. Since then also I have changed my Receiver several times, going thru various brands, namely Pioneer, Pioneer Elite, Yamaha and finally Denon. But in my professional capacity I have had the opportunity to work with several other brands also, some that are from the very high end of the market. I have done Home Theater setups costing upto US$75000. I have over the years also accumullated a collection of over 300 Laser Discs and approx 1300 DVDs. All this I mention only to show that I do have a little if not much experience and knowledge in this field. By the way, I also have friends/clients who own some of the nicest movie theaters in Delhi and therefor I have had a chance to work with professional theater equipment also.
Regarding Home Theater and the issue of Sound formats let me state my understanding of the terms:
Channels = Number of decoded signals output.
Tracks = Number of actual/discreet encoded channels, which may or may not have further channels matrixed into them.
Stereo = A term used to describe a 2 channel system.
Encoding formats:
PCM = Pulse Code Modulation = The technical term for how the sound is encoded on a regular Redbook CD. It is also one of the permissable alternates (alternate to Dolby Digital/AC3) for DVD encoding. PCM is the only Digital fromat that does not use some form of compression.
Dolby Surround = Encoded 2 analogue tracks / Decoded 3 channels
Dolby ProLogic = Encoded 2 analogue tracks / Decoded 4 channels
AC3 = Audio Coder 3 = Literally the third audio coder developed by Dolby Labs. In the intial stages of Dolby's Digital Format it was simply known as Dolby Surround - AC3
Dolby Digital/AC3 (in the case of Laser Discs) = Encoded 5 to 5.1 digital tracks / Decoded 5 to 5.1 channels
Dolby Digital/AC3 (In the case of DVDs)= Encoded 1 to 5.1 digital tracks / Decoded 1 to 5.1 channels
Dolby Digital EX = Encoded 5.1 digital tracks / Decoded 6.1 channels
DTS = Encoded 5.1 Digital tracks / Decoded 5.1 channels
DTS ES = Encoded 5.1 digital tracks / Decoded 6.1 channels
DTS ES 6.1 (also known as DTS ES discreet) = Encoded 6.1 digital tracks / Decoded 6.1 channels
MLP = Meridian Lossless Packing = A lossless compression format used to encode 5.1 channels of very high quality audio. It is the standard for DVD Audio. IT is also one of the contenders for the audio specs of a future HD DVD format.
SDDS = Sony Dynamic Digital Sound = A digital format, with upto 8 discreet channels, a format restricted to theatrical releases only. As per Sony no plans of a Home Theater version ever.
Post Processing:
Post processing in Receivers/Pre Pros has been around for ages, and from numerous manufacturers with various names, more generacally known as DSP modes. Yamaha is known to have taken the lead in this field previously. These are pseudo formats and not related to encoding or actual decoding but rather they are applied post decoding.
DTS Neo = Post processing to create 6.1 channels from stereo encoded signals.
Dolby ProLogic II = Decoding of Dolby ProLogic and further Post processing to create 5.1 channels of higher dynamics than the decoded signals from the original Dolby ProLogic decoder. It is also a post processing format that creates 5.1 channels from stereo encoded channels.
Denon 5.1/6.1/7.1 stereo = Post processing to create 5.1/6.1/7.1 channels from Stereo encoded signals
Almost all manufacturers now have something similar to the Denon 5.1/6.1/7.1 stereo mode.
Regarding THX, now this requires a more indepth explanation to avoid confusion. Previously there was only one kind of certification by the name of THX. THX is nothing more than just a certification of certain quality standards, except in the case of Receivers/Pre Pros. In the case of Receivers/Pre Pros THX also does some post processing. But this processing does not involve decodiing and/or increasing the number of channels. At a later stage THX split up their certification into standards, namely 'THX Select' & 'THX Ultra'. 'THX Ultra' has now been labelled 'THX Ultra 2' due to certain changes in the certification process.
Equipment that meets with THX approval falls into either the Select or the Ultra2 category. While Select-certified gear tends to be less expensive than Ultra2 gear, the labels aren't based on quality or price but on the room size the component is best suited for. THX Select gear works best in smaller rooms or in rooms where you'll be sitting closer to the speakers, while Ultra2 gear is suited for larger rooms (approximately 3,000 cubic feet or more) where you are likely to be sitting farther away from the speakers.
Ultra2 was introduced in 2001 to replace the 10-year-old Ultra specs, which were the same as the specs for THX certification before the program was split into the Ultra and Select categories. The main mission of the Ultra2 program is to simplify and improve film and music playback over 5.1- and 6.1-channel systems.
The lowest THX rating, THX Select, is awarded to good midprice gear, while THX Ultra2 (an upgrade of plain old THX Ultra) is reserved for high-performance, premium-price gear with state-of-the-art features.
THX Ultra2 differs from its predecessor only in two ways. One by mandating full 7.1-channel playback capabilities for Dolby Digital Surround EX and DTS-ES soundtracks, which add a back surround channel for one or two speakers centered behind the listening position. To be certified as THX Ultra2, a receiver has to provide not only decoding for 7.1 channels and processing to derive 6.1- or 7.1-channel playback from 5.1-channel sources, but also seven discrete amplifier channels as well as “boundary gain compensation†to help match a subwoofer’s output to the room acoustics regardless of its placement. The other change from the old THX Ultra to THX Ultra2 requires that a receiver have wideband component-video switching to handle signals from a progressive-scan DVD player or a high-definition TV (HDTV) tuner without picture degradation.
Do keep in mind, that THX in neither of it's two versions does any decoding, nor does it increase the number of channels. All THX post processing is limited to just de-colloration of the sound to suit home environments.
In closing, what I am trying to say thru this post, is that to decide about surround formats and how many types there are, one should take into account only the encoding and decoding process and not the post processing done after the decoding. Because if we were to start naming formats based on various claims of manufacturers based on their DSP capabilities, then believe me there would be no end to the number of formats.
Edited By Sanjay on 1038827517
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n your quote, I'll try to ask you to elaborate yaar!!
