[Karlsson]

Hello,

Not a new member here, but have been away for awhile and had to re-register.
Thanks for your attention!

I’d like to keep my strictly 2-channel rig to drive only my front mains, and buy a 5.1 receiver to drive only the center, subwoofer, and 2 rear channels only when watching movies.

Can this be done? Should I be looking for an older surround receiver? I don’t have a clue frankly.

My system consists of:  Wright WLA-12A tube preamp, Smart systems hybrid stereo amp, Panasonic DMP-BD60 blu-ray player (has analog audio out L+R, not 7.1, one HDMI), Panasonic plasma TH-50PX600U (two HDMI), BG Radia speakers– fronts, center, rear, and ACI Force subwoofer. Subwoofer is currently hooked up to one of the Wright’s preamp outputs.

[Bob in St. Louis]

Welcome back Karlsson. 

I'm sure it can be done, but to date, I've not found a good reliable way to get it done and retain the two channel sound quality.
Suffice it to say that I'll be interested in hearing some ideas.

Bob

[srb]

With a preamp that does not have a Home Theater Bypass input (a unity gain input that bypasses the preamp's volume control), you will need to mark a position on the volume control to return to when you select that input for watching movies.

You will want a more modern HT receiver with

(a) HDMI input (to be able to decode Blu-ray Dolby True-HD and DTS-HD Master Audio soundtracks) as your Blu-ray player does not have 5.1/7.1 analog outputs

(b) 5.1/7.1 Preamp outputs (or at least a minimum of Front L/R + subwoofer preamp outputs) to connect the Front L & R channels to a line input on your preamp

The problem that often arises is how to connect a subwoofer to both your 2 channel preamp and HT receiver.  In your case, looking at the pictures I could find of the ACI Force subwoofer it appears that it has both L/R inputs as well as a theater input (also marked LFE on some other subwoofers).

The subwoofer preamp output from the HT receiver would get connected to the subwoofer Theater input.  This input bypasses the subwoofer's internal crossover which would be controlled by the HT receiver subwoofer settings.

The potential problem is that since there is not a switch on the subwoofer to switch between L/R and Theater inputs, it's possible you may have to disconnect the L/R inputs when watching movies if the overall bass level is too much.  To try and prevent this, you would want to set the receiver's Front L/R speakers to "large" in setup to prevent the receiver from directing normal bass frequencies to them which are already being sent to the subwoofer's L/R inputs from the preamp.  Then the subwoofer's Theatre input would only be receiving LFE sound effects information.

When you want to watch a movie you would select the "HT" line input on the preamp and set the preamp volume control to the marked HT setting that was predetermined when you set up the receiver's speaker levels in the speaker setup.

Steve

[Phil A]

In more than one system, I use a 2-channel preamp with HT Bypass and Rel subs which have both a high and low level input along with a separate volume control and very flexible crossover for the high level input which goes to the amplifier (I use stereo subs in the main system). So when I listen to 2-channel I don't have to switch anything and the same HT (in the main system I don't even need to turn on my preamp as it defaults to bypass while off).

[WGH]

I use an Outlaw 975 to turn my 2 channel into 5.1 for movies (an Emotiva UMC-200 would operate the same). My main speakers have plenty of bass so the sub is used only for movies. A 3 channel amp would handle the surrounds and center channel, I have plenty of old amps laying around so use an old Adcom for the surrounds and an NAD for the center, not pretty but affordable.

The Blu-ray (HDMI), TV HDMI (using the ARC function), and computer (HDMI) are plugged into the Outlaw inputs.

The Digital Music player/DAC, Tuner, Phono, and Front L/R (from Outlaw) are plugged into the Pre-Amp inputs (4). The volume is set to a little over 1/2 for movies.

Replace the ACI Force subwoofer with a REL Gibraltar G-2 because it has 2 inputs, one for stereo and one for home theater:
"(The) G-2 possesses a dedicated Dolby .1 LFE input with its own 4th order crossover set at the Dolby mandated 120Hz and we outfit this circuit with its own separate volume control allowing G-2 to simultaneously reproduce the deepest bass for main speakers as well as home theater signals, all without having to invest in separate subs for each purpose. Additionally, G-2 provides independent volume for High level as well as .1 for perfect flexibility."

The REL remote fine tunes the bass and would probably be the most used remote in the house.

[srb]

Replace the ACI Force subwoofer with a REL Gibraltar G-2

Replace the ACI with a $3500 subwoofer?  Easy Peasy! 

Steve

[WGH]

I like spending other people's money 

[mcgsxr]

I think the truth is it depends on what compromises you are willing to make.

In my case, I sold off all my 2 channel gear, and initially built up a 5.1 in my basement this past Spring.  I later discerned that the 2 channel enjoyment was missing, so I changed the front 2 speakers, and added a 2 channel amp to drive them (both for 2 channel and HT).

I use my AVR as the preamp for the front 2 channels, and as the amp for the center and rears as you describe.

In your case, unless your preamp has an HT bypass, I am doubtful it can be done with what you have.

You could search out a modern AVR with pre-outs for at least the front 2 channels and leave your preamp out.  Not sure what your system would sound like in 2 channel with an AVR doing the pre work, but it would certainly be the easiest way I can think of, and likely affordable too. 

The used Pioneer AVR I bought was around $200, and it has pre-outs for all channels.  I am only using an outboard amp for the mains, as I expect you would too.

[low.pfile]

Karlsson
It seems like you just need to pick up a A/V Receiver with Pre-Outs (to send the video Front Left and Right signals to your Pre-amp). That is what I used to integrate my 2 channel with my 5.1 AVR. My preamp has HT bypass but I preferred to use it in regular input mode.

In my combo system setup, the levels, crossover, and bass management are handled by the AVR. But, when using the 5.1 set up, because the Front Left and Right are being powered by different amp than the other channels, you will have to find the appropriate level on your Pre-amp to match the center. Easy to do on modern A/V Receivers with their built-in white/pink noise generator, either do it by ear or hand held meter. just do this once and make a mark on your preamp volume knob.

I am not clear on whether you want to use your subwoofer in both the 2ch music and 5.1 AV configuration. That may not be as straightforward-some of the pros on AC might help out here. I did not utilize my subwoofer in my 2 channel music system, but if I want to add the extra reach of the sub into the music system can by manually remove the single RCA cable (from the AVR to sub) and connect a separate stereo RCA cable pair from the pre-amp output to the sub. FWIW, I have a older Martin Logan Abyss sub.

For reference a diagram of my setup



This topic has come up before on AC, one thread is here http://www.audiocircle.com/index.php?topic=81757.0

hope that gets you started...

[Karlsson]

Hey all,

Much appreciated! That's quite a bit of info for me to get a great head start with. I still have to purchase a receiver, then I can get going with rear speaker mounting, running cables, etc.

[Mr Peabody]

Depending on how picky you are....  I found that mixing tubes in with solid state HT to drive me crazy, the difference in sound stood out to me like a full moon.  To a lesser extent the same with mixed brands of amps and speakers.  Also, do you really want to burn tube life for HT?

My solution is to have two completely separate systems that share the main L/R speakers.  I use banana plugs for quick switch and just physically switch the cable to the system I want to use.  You using a sub complicates this some but Steve said you have two separate inputs.  So I assume the auto turn on will activate based on which input the signal comes in on.  You use your HT receiver and BDP for HT and your tube system and sources for 2-channel as you are now.