Basic Question: How to add Center Speakr to 2-channel system

Kenyonlands

Kenyonlands

New Member
Hello to all, I'm new to the site and not well versed in all of the technical terms but am learning a lot and reading a lot of threads on this site, looking for the answer, so please forgive if this is an old hat question:

I have your basic analog 2-channel pre-amp/tuner (Adcom GTP-450) and 2-channel Adcom GFA-555II amp, with a three-speaker switch box atop it (GFS-1), a Sony 27" CRT TV; system components and TV are all about 14 years old, e.g. not digital 'cept for maybe the CD player and Samsung DVD (newer, in past 3 years - hate it, sometimes it works, sometimes it just sits there with a frozen screen:thumbsdn:).

The amp regularly runs two sets of B&Ws that are in the same room; their positions could easily translate into a 5.1 system, minus a subwoofer (803's in front, old DM14s in the rear). Currently, it's an audio system and the TV just happens to occupy the cabinet next door (DVD is plugged into TV directly).

Okay, to the Question: To turn this into a basic (mostly analog) home theatre, can I add a center speaker to handle the voice, buy a larger switch box (have seen one w/six buttons, only would need 4) and run the two B&W sets and the Center channel off the current amp? Will this work?

But the follow-on question (from my reading here) is, how do the "voices" from the TV/DVD know to get to the center channel w/o an HT receiver to tell them? And, what is a "phantom center" I see referred to in some threads?

Look forward to your responses.

I admire everyone's openness and the free-flow of ideas; its has been enjoyable to partake of this experience at AudioKarma.org.
 
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you are not going to be able to do things as it stands now, you need a reciever or a processor made for 5.1,7.1 to get the affect you are after. You could get an old Prologic reciever for pennies on the dollar to handle basic decodeing or a budget used or new dolby digital unit, a reciever ofcourse would provide an amp for the center and surrounds which would be cheaper route vs processor and outboard amps needed for same results, if you do happen to get a reciever make sure it has pre outs for front speakers if you wish to use you current amps. Not only will the reciever decode the channels and amplify them but will also have crossover and delay, distance settings.
There is alot more info others and myself could go into at a later time but for now you really cant do what you want with gear you have.
 
The early Yamaha DSP units were designed to adapt existing components for a 4.1 or 5.1 system...
 
You would need a surround sound processor to decode the 5.1 info from the DVD and five discrete amplifier channels and speakers.
 
If you just want a 3rd speaker in the center of your room outputing the same stereo source as the other 2 without getting into the surround world you can get a 6 channel power amplifier. I have one by Rotel, the RB-976.
 
Sure, you can link the channels, but what ever speaker is used for the center would contain only the left channel information or only the right channel information. There would be no summing of dialog from both channels, etc.
 
some pre-amps have a center channel output, like the Marantz 3300 (I used to have one, sold it and now i think I should have kept it :tears:)
 
IMO, even with surround sound, a center isn't needed. With properly set up mains, the center image from the two can be more realistic than having a center speaker. I've been running 4.1 for a year now and couldn't be happier with the setup. I just feel bad for my lonely center speaker sitting in the closet. :D
 
Some are happy with no center or phantom mode but most are not, there is good reason center channels are so popular, many have a hard time hearing dialogue with no center and still others that have multiple people in listening room off axis dont get acceptable results without anchored dialoge from a properly positioned center. Try it is you can but dont be surprised if it doesnt work for you.......you are not going to be alone.
 
Well...you gotta have a surround system to run a center channel regardless if it is a phantom center or a real center channel. The OP does not have a surround system.
 
Chadnliz, Avionic, Kassanova, Whoaru99, Face and the others, thank you for your honest and straight-forward opinions. (Sorry, was out all day and couldn't respond.) This is kind of what I thought was needed - some other piece of equipment to send signal to the center. I like the idea of getting a used surround sound receiver that had it's own amp and use it just for the center channel.

chadnliz said:
...if you do happen to get a reciever make sure it has pre outs for front speakers if you wish to use you current amps. Not only will the reciever decode the channels and amplify them but will also have crossover and delay, distance settings....
Click to expand...

Chadnliz, so with your suggestion, the pre outs from the receiver can go down to my two channel amp where the other the front and rear sets of speakers are switched, right?

So, at best, I'll get surround sound w/the two fronts and the center, is that also correct? I only have the one amp.

This setup sounds, though, like the receiver is going to need to replace the Adcom pre-amp/tuner, no?
 
Any suggested receiver models I could start researching, get used, something fairly simple w/surround sound?

Knowing my system (first post on this thread), what's anyone's opinion on: Marantz SR7000...or...Rotel RSX-1055? Both seem to have Pre-outs, as suggested by Chadnliz.
 
If you do with a receiver, here is detail to consider. I think some newer HT receivers do not display enough information on the built-in display to allow for configuration and adjustment. This requires you to now route the video signal thru the receiver so you can superimpose the configuration menus on your TV.

I have a Marantz SR7000. It does use menus displayed on the TV to access settings, but the main display also has (barely) enough information to perform configuration. I also have an old (2002?) Harman Kardon AVR 125 which also displays configuration info on the main unit. I like the configuration options on the HK better. Not sure if I could have figured out the config on the Marantz without the TV menus at first.

I also recommend going one generation newer than Pro-Logic. Dolby Digital is a big step up from Pro Logic IMHO.

The real trick is going to be dealing with your rear speakers. Right now, they are playing what ever comes out of the fronts. In 5.1, they need to play a different signal than the fronts. So, they will need a separate amp. I doubt you want to swap your Adcom with whatever is in a receiver. My guess is that you want your surround system to be an add-on to the current 2-ch setup, and not fundamentally change it. If so, I don't really know how to handle this. You'll need a separate amp and the ability to select sources (main 2-ch or rear surround) for the rear speakers.
 
bholio said:
...I also recommend going one generation newer than Pro-Logic. Dolby Digital is a big step up from Pro Logic IMHO.

The real trick is going to be dealing with your rear speakers. Right now, they are playing what ever comes out of the fronts. In 5.1, they need to play a different signal than the fronts....So, they will need a separate amp. I doubt you want to swap your Adcom with whatever is in a receiver...
Click to expand...

Bholio, you've caught the spirit of what I'd like to do. Thanks for the heads-up on the on-screen configuration and routing thru the TV for the Marantz and HK AVR 125 - I saw that model in my research last night. And, you're right, it's probably thinking too short to go Pro Logic vs dolby digital.

Okay. Do you think this idea will work with a receiver: Get a newer Dolby Digital receiver with the pre-outs (pls. suggest a model or two), drive the center and rears (surrounds) with the receiver and send the signal for the front speakers thru the pre-outs to the existing Adcom amp? (you're correct, I want to keep the existing amp involved, esp. for driving the 803's in front) Does the signal processing work in this manner?? Can it throw signal to pre-outs at same time as to speakers connected directly to receiver?

I guess I lose switchability between the two sets of speakers (fronts and rears) if do it this way, don't I?
 
Kenyonlands said:
Okay. Do you think this idea will work with a receiver: Get a newer Dolby Digital receiver with the pre-outs (pls. suggest a model or two), drive the center and rears (surrounds) with the receiver and send the signal for the front speakers thru the pre-outs to the existing Adcom amp? (you're correct, I want to keep the existing amp involved, esp. for driving the 803's in front) Does the signal processing work in this manner?? Can it throw signal to pre-outs at same time as to speakers connected directly to receiver?

I guess I lose switchability between the two sets of speakers (fronts and rears) if do it this way, don't I?
Click to expand...

I didn't look back through the thread to see what is the deal with your rear speakers. But, using the receiver to power the center and surrounds and an outboard amp for the front/main speakers is very common.

The signal processing works just fine doing that, and the pre outs will carry signal at the same time as the speaker outputs.

A new receiver with pre outs and all the goodies usually comes at a price and you don't often find them until midpoint or upper end of the product lines. If you don't need HDMI and the latest, greatest bells and whistles, you should be able to find a very nice used receiver with Dolby Digital, DTS, etc. and pre outs for much less.
 
whoaru99 said:
But, using the receiver to power the center and surrounds and an outboard amp for the front/main speakers is very common.

The signal processing works just fine doing that, and the pre outs will carry signal at the same time as the speaker outputs.
Click to expand...

Great to have that confirmed, Whoaru99.

Regarding your last paragraph, I'll be on the lookout for the used receiver that's a few years old but one w/pre-outs - I don't need the bells & whistles or HDMI; just looking to move slowly into HT, play with it a little and try and keep the dollars down. Despite the February HD deadline, am planning to keep my old tube TV - I don't have an extensive DVD collection, my focus is still the music!

Thanks to all who've responded - my direction is much clearer.
 
Another useful feature to keep an eye out for is '5 ch stereo'. This is a mode where 2-ch audio is played out thru all of the surround speakers. I find this feature very useful on the SR7000 (which I only use for 2-ch audio and A/V switching). The HK 125 also has it. You will need it to keep your rear speakers playing 2-ch music.

My (older) Yamaha RX-V2090 (pro logic era) does not have this feature and I cannot play 2-CH music thru the rear channels properly.

It might be a standard for dolby digital receivers. My AVR125 is bottom of the line for HK that year and it still has it.
 
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