Confused about 7.1 Formats

I am a bit confused about all these formats (kind of new to all this). I have been looking at the Anthem AVM20 and the new Krell Showcase coming out soon. The thing is that they are all 7.1 pre/pros -- does this mean I need a seven speaker setup? What would happen if I wanted to watch a DVD such as Gladiator and I have a 5.1 setup for speakers? Will it work properly or will I be missing something. Isn't the DVD encoded with 5.1 so it will only play 5.1, if so is the only reason they call it 7.1 is for when movies start coming out on THX Ultra 2 and the like?

Thanks for all the clarification, just nervous as I am working on a tight budget -- two speakers extra means more $$$.

I'm not familiar with the particular equipment you describe nor whether there actually is a 7.1 format encoding / decoding scheme. I have a Lexicon processor that uses proprietary signal processing to extract far right and left information that is sent to two additional speakers. Personally, I wouldn't do HT without it, it makes a huge difference.
The 5.1 are all discrete channels. The other higher versions start matrixing the information out of those original. A center rear matrix's the info from the two rears (unless the center rear is actually being recorded as a discrete channel-that I don't know). And 7.1 with two additional surrounds (but no center rear) matrix's the sound from the rears also. I think. Dolby Pro-Logic was only 2 discrete channels with the center and surround matrixed out of those. I think I've seen 8.1 somewhere.
Any new speakers (i.e. channels of info whether or not discrete or matrixed) will need more amps. Upstream at the heart of things I'm not sure on the processer and dvd player compatabilities. But you always have the option of not using the additional channels.
7.1 means several things

if you are a neanderthal and are wowed easily it means "more is better"

if you are george lucas it means "big moula"

if you are a typical audiofile that can set up something right in two channel it means "why waste my time"
Audiotomb, that's great! Jplenhart, Anthem is a fine a/v processor/switch and will very likely allow you to use a 5.1 format or even a 3.1 format if you don't want rear speakers. The WAF goes way down as you increase the number of speakers. Ask the dealer or check out the website to confirm the optional set-ups for the Anthem. Think of al the DVD's you could buy or rent with the savings in speaker and amp costs! Have fun!
P.S. Personally, I like at least a center channel while watching a movie -- but I'm unable to get the appropriate soundstage since my TV is between my speakers. A lot of your final setup and choice to go to 3, 5 or 7 speakers/amps(plus subwoofer) depends on your room size and ability to choose function over form.
There are no Dolby or DTS 7.1 formats.

The DTS-ES Discrete 6.1 format actually delivers a discrete rear center channel.

Dolby Digital EX Matrix 6.1 and DTS-ES Matrix 6.1 both encode the rear channels in a manner similar to Dolby Pro Logic so that a rear center channel can be derived.

P.S. If you haven't heard about the Chesky 6.0 format, you should take a look at the following website:

I guess I am a bit confused about using 7.1 format pre/pro. If I have a 7.1 pre/pro but a 5.1 speaker setup, will this work - in other words does 7.1 mean it can do 7.1 and down?


Jp, go to to get the specs, manual etc. on the AVM 20. If that doesn't work, go to A 7.1 setup requires 7 speakers plus a powered subwoofer and seven channels of amplification. A 5.1 setup requires 5 speakers plus a powered subwoofer and five channels of amplification. Most good audio video preamps/processors will allow you, with menu options, to use fewer channels if you choose to do that. Since many DVD formats offer six channels of sound (subwoofer -- which is the .1, front center, front left, front right, rear left, rear right), choosing to use fewer speakers and amps will mean that you are choosing not to utilize all the info that is sent. So, going to a front right, front center, front left and subwoofer setup means that you will not hear the rear sound effects. The 7.1 setup (per my understanding), would normally still rely on the same six channels of sound provided on the DVD. An internal processor enhances the information to provide a more spacious sound field -- but there is no new information above what is on the DVD's six channels of sound. I believe that some new DVD formats allow a seventh channel which can then be split to two speakers (i.e., 6.1). I don't believe that is very prevalent today but tomorrow ...? Basically, the 7.1 allows you the opportunity to synthesize the extra channels for most DVD formats and provide you some growth for the future when new formats utilizing more channels are available (I am, however, not a fortune teller). Please check out the Anthem site for more details. Also, the site is very useful. Folks, I'm probably in over my head here, so please feel free to correct me.
I was on a flight this week and picked up some HT mags, Sound and Vision and one other that I can't remember, not Stereophile GHT because I sub to that one. Anyway, one of them featured the new THX Ultra2 system and explain the new 7.1 decoding and setup in great detail. You might look to find that rag and learn a great deal.
i think you have it right: a 7.1 preamp can do 7.1 and down.
I am currently running a 7.1 surround theater.There are know 7.1 dvd's as of yet but there are a few 6.1 discrete the 7.1 format is a long way off I think as there are so few 6.1 to date.I have a Denon AVR-3802 reciever wich has 110x7 watts but will not do 7.1 discrete,only 6.1 discrete and matrix and I also have a wide screen mode that claims to produce 7.1 from a 5.1 format.All and all with the 2 rear channel speakers the sound is awsome and I highly recommend using this set up as the dvd formats are improving every day.As for your set up it will cost you alot of money to do this right using amp/pre amp method becouse a 7 channel amp will run you about 3,500 dollars but if you have your hart set on that method check out B&K products.Other wise if you want to use your system mostly for home theater I would look in to audio video recievers.It will save you money and still get great sound from your movies.