surround processor?

Where to go? Older Lyngdorf MP50, JBL SDP-55,Arcam AV40.Lexicon MC ( the cheapest)? Love to watch the movies but also listened to 2 channel stereo. Are there a big sound difference in those? Just the general advice please. Will probably look into second hand.
Wasted a year, maybe two, chasing this one. Easily the worst thing you can do is add channels. The processor alone, merely having it connected nothing even going through it, however you want to call it, even that harms stereo quality. They are just the noisiest thing, much worse than a DAC, CDP or streamer. They cost money that takes away from where it could actually do some good. Extra speakers, amps and cables means only being able to afford worse ones for where it matters, the stereo.  

That is why after two years banging my head against marketing and the CW I finally got up the courage to buck the trend and do it right. I wish you well.
If 2-channel is very important to you, IMHO it’s best to use a dedicated stereo preamp or integrated and hook the front L/R preouts of the AVP into it. 
soix, I assume in the setup you describe the AVP is out of the loop for stereo, but its L/R preouts go to by-pass inputs of the preamp for surround. That’s the setup I use. HDMI input to a Bryston SP3, balanced analog from the SP3 to an Ayre preamp. Balanced analog stereo inputs go directly to the preamp, so the SP3 is out of the loop.
Best to have two separate systems, sharing only some sources if desired.
Then you can enjoy surround AND the best of stereo that you can muster.
Recently i began a search for components for a music only 2.0 system. The heart is a Parasound Hint6. It had a feature i dont use the HT Bypasss feature that lets me use the Hint6’s 160watts per ch amp for either music or HT.

so, you could use one of those horrible sounding multich receivers in attempts to recreate what the director intended, or just wall of sound it like some people do, stereo is fine for some folks year round
A good option would be to get a used Classe Sigma SSP MKii (if you can find one as they are out of production). The 2 channel function is based on the highly rated Classe CP 800 preamp. There are probably better options if your focus is 7.1, but it performs well enough and the 2 channel is very good through the USB input or analog XLR. I use a Lumin streamer and connect it via analog XLR with the Sigma in bypass mode.
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No question separate systems are the best. Basically you have to buy two separate systems and integrate them in the same location, which forces physical space trade offs. If at all possible do two separate systems in separate locations.
If you can find one, the Angstrom 200 Surround Sound Processor / DAC / Pre-Amp, designed and built by Mike Moffat of Theta and Schitt Audio.
Although my setup is all balanced Ayre 5 series with a Bryston SP3 used only for surround, I suspect the SP3 itself would make a fine preamp/processor.

I see no need for separate locations. The Ayre preamp and amp drive a pair of KEF Reference 1s and a pair of Velodyne HGS-15s with an SMS-1 bass manager. The SP3 and amps drive a KEF Reference 204/2C center speaker and four KEF LS50 surrounds. All in one location. I have a third HGS-15 that I plan to hook up to the SP3 for LFE.
The first thing to do is forget the notion that stereo recordings must be reproduced with two channels. Recordings maybe mixed down to stereo as it is a better format than mono but it's no reason to insist they must be heard in stereo. Dolby surround does an excellent job and it enhances the listening experience.

It is crucial to set speaker distances as accurately as possible (small hand held lasers are ideal and far better than tape measures). Balancing levels is critical.

I recommend having all speakers from the same manufacturer and if possible the same series. Pre outs are best and identical amplification is ideal as the last thing you want is each channel having a different "sound". Some home theatre systems allow you to turn amplification off and the massive power supplies are then ideal for surround processing.

Five point one is a good starting point, but adding two front wide speakers and two rear surrounds really encases you with sound. That's nine point one and adding four Atmos speakers completes the package.

Four subs really makes a massive difference. I prefer to have them equidistance from the main listening position.

Another crucial consideration is adding super tweeters to each loudspeaker. The difference is so incredible it is unbelievable. The best way to describe it is the recorded sound disappears and you are there hearing sounds as they were recorded. Townshend SuperTweeters are excellent but the cost for multichannels is prohibitive. I've found that BatPure are ideal and they have a higher frequency range. They only have one output level, which is basically the same as Towenhend's position one.

Movies and music are spectacular.

I've mentioned this previously, but it's worth mentioning once more. Loudspeakers can be greatly enhanced by reducing sounds bouncing around in cabinets and contaminating cone movement. Lining the cabinets with sound deadening material and filling the internal space with sound absorption material works a treat,
Millercarbon is a 2 channel purist but don’t hold that against him. He gets it right 100% of the time otherwise :)

I can say this with 100% assurety.
Find a lightly used Classe SSP-800 on EBay or elsewhere. There is one listed now on EBay for $1200! And you could make an offer for $1,000 and he might accept. There is 1 on U.S. Audio Mart for $2100 CAD or $1600 U.S. I’ve seen them awhile back for $2600-3400....I paid $8,000. The only risk is no returns on the EBay one.... So investigation is warranted. But, if it is like mine, it is a tank.

I have 1 and have had it since it near first came out in 2009. 12 years without so much as a hiccup. The SSP has excellent surround and excellent 2 channel. I mean excellent. There is an unadulterated analog pass through/digital bypass and I will soon hook up a Rogue Audio Ares Magnum tube phono preamp to it.......The only thing it doesn’t have is Dolby Atmos and another 1 but you can upgrade the SSP with an upgraded DSP card for $999 and get them.

It also has a great DAC. I stream an upgraded Node 2i to it and it sounds fantastic. The 5.1 surround is excellent as well.

You can have the best of both worlds. 2 channel and surround. At $1000-$1200 or $1600 you cannot touch it with any other processor in the world.

There are several stellar reviews online. One being Robert Harley from TAS who absolutely loved it.

And this review:
And I’d be happy to help you out in any way I can should you have any questions.
Good luck!
you might rethink that 100% grade, do some research on what he thinks of digital. Square that up, if you can….
Yeah. He’s a true analog guy. Nothing wrong with that. I like digital when I’m home from work or cleaning the house etc where I don't want to fuss with albums.....Digital can sound very good. But for true immersive music, I love vinyl better.

But the OP is talkin’ ’bout AV processors.
I have a 5.1 channel MC-12 I no longer use. I’ve been meaning to post and sell it. I loved it for surround sound, nothing close to it, very flexible, an amazing pre-amp for that use. Matches well with any high quality amp. 2-channel was good, but still no where near the quality of a dedicated 2-channel. Just depends on what’s most important to you.
Imho, 'surround' can work....but it has to be approached with the care that MC has towards 2chan....but, again, mho
2 speaker and home theater are entirely different. You listen differently. HT is a visual experience with potentially a great immersive sound. I don’t listen to my Marantz 11.2 system for the accuracy of the gun shot sound. I do listen to my 2 speaker pass labs system for the accuracy of the piano. HT subs should literally shake you. 2 speaker setups should have subs that extend and melt into the sounds of your front speakers. My surround sound speakers don’t begin to match the quality of my 2 speakers. And they don’t have to. Having a creepy sound behind you doesn’t have to come out of $20k speakers. I love both setups. But HT and 2 speaker are mostly different systems because we listen differently to each setup. To answer your question, I bought the Marantz many years ago because of the 13 channels and the auro 3D. It’s modestly priced and works well. 
Make sure what you get will do at least 4K video, the Classe mentioned above does not.
Make sure what you get will do at least 4K video

Absolutely. Clarity of sound and clarity of image are the way to go. Substandard surround speakers are like a substandard center speaker; not recommended for those who appreciate quality.
Two channel needs its own dedicated system. There are many here that claim to have found the holy grail of doing 7-1, 8-1 and 2 channel from the same system. If they are happy with their system and the sound it is not my place to question them. I know from my personal quest it is different. I went into hibernation for 10 years on audio file 2 channel. Dove head first into surround sound ( current is 9-2). The in home experience watching a movie is fantastic and love it. I played cd’s through the dvd player, watched concerts and they all sounded really good to my ears. Then I got the itch to put my tt back into play and started listening. The more I listened the more I felt something was missing. I stopped by an old friends home and he has a great 2 channel system. It only took the first song for me to realize the injustice my system was doing to 2 channel. Left his home and started the journey of dedicated 2 channel and have never looked back. In summary my left side cabinet is surround and my right side cabinet is 2 channel. My wife hates it but as more time has passed I don’t even hear her any more. She is like the teacher for the peanuts! At the end of the day only one thing matters. Enjoy the music!
Agree with Vinylshadow on the Classe SSP 800.  The Classe Sigma SSP, that I have, was a newer, and less expensive model when it came out. However, it also has a great DAC for 2 channel.  The SSP 800 is a better choice if you prioritize multi channel as all channels are fully balanced, while the Sigma is only fully balanced for 2 channel.
Hello killervideo.  Emotiva makes a very reasonable unit, the MC-700. It sounds great and surpasses any of the receivers with preamp outs that can be used as a front end." (Although they will give you more surround sound synthesizing options.) If you ask for a refurbed unit, you can get a discount. It has room correction capability and works very well in my main system. Enjoy!
Look into a McIntosh av processor to start and as you move up your two channel game you can add a two channel preamp and use the home theater bypass option. I use an mx 120 for av and switch over to a c2300 tube pre for two channel. Great flexibility without sacrificing sound quality. 
Somehow the language got so distorted people think Home Theater means Multichannel. This was a Jedi mind trick. Does "home" mean multi-channel? What about "theater"? So how did "home theater" come to mean dogmatically multi-channel? 

Discuss among yourselves. I already know the answer.
To follow up on MC, I have been deeply involved it the creation of world class multi channel HT where just the room was $250K ++.
Especially so, I have never considered any other than two channel.
To create an audiophile level HT indeed takes hundreds of thousands. Not to mention a LOT of complex gear. And unless there is a room within a room for proper speaker placement, there are a LOT of speakers scattered around the room and a LOT of cabling.
And even in the above mentioned HTs, the cabling and speakers are not what I consider to be SOTA, audiophile level. And even the amplification is not at that level. Personally, I am quite happy with my quality 2.1 channel system for Audio and HT. 
Skepticism about mixing 2-channel with multi-channel makes me think it must be imagined that a balanced connection to a preamp input set to by-pass somehow corrupts the preamp when it is used for 2-channel even when the input and the source for that input, i.e., the processor, are both inactive.  Seems like the magical thinking that's all too common in audiophilia.
It is not skepticism. If you would bother to read you would know it is experience. Skepticism is theoretical. What someone thinks. Experience is actual, what actually happened. In this case my actual experience was the exact opposite of my expectations. Any skepticism I may have had was being skeptical stereo could do the job. It was only after two full years of trying all kinds of multi-channel solutions that I came to the conclusion multi-channel is a marketing ploy and a fool's game. The primary goal of multi-channel is to sell more stuff. At this it is an unparalleled success.

Magical thinking is when you invent a narrative and then try to pretend reality will somehow bend to match your fantasy. When you do this, which you just did, psychologists call it projection.

This is especially apparent in light of your post following immediately on the heels of Mglik, an industry professional and audiophile who just corroborated everything I have been saying. Please, read what is written. Respond to what exists. Don't deny reality, go making stuff up, and then have the temerity to say the other guy is "magical thinking". 
I too believed that 13 channel home theatre systems were excessive and unnecessary, but after experiencing the additional channels I discovered they do enhance movie experience irrespective of room size as they provide a smooth transgression, rather than jumping from speaker to speaker.

What I fail to comprehend is how and why dedicated stereo system are always assumed to be better than home theatre systems in stereo mode. Home theatre systems have decent DACs and by selecting stereo mode the multi channel processing is removed.

Could it be that as soon as multi speakers are observed there is an automatic assumption the sound is always going to be inferior? It just seems irrational and I hope someone can explain it. Perhaps the issue is with the word theatre as sound in theatres is always a compromise.
Just like MC I have tried to squeeze every two channel sound out of a surround system by itself. Some stuff helped the sound quite a bit like a better cables. Especially a better power cord. After listening to other systems at friends and stores I knew I needed to do something different. I like the Denon H3600x ($900) or the H3700x ($1100 and does up-to 120hz. In 4K) for the surround sound receiver. It is one of the few SS receivers that you can divert the amps from the front and use them for the surrounds. Then you can look for a two channel option with a decent bypass. Just so you know every time you use one of the amps inside you are probably cutting the watts per channel to all the amps you are using. It’s just plain physics. I use the Emotiva XSP 1 preamp with a Marsh Sound Design amp. It is full linear differential balanced. It even has a built in crossover for the subs. It is great for  the $1100 new price tag or $800 used. I bought mine used. This system works great. I tried the Rogue RP7 preamp but it did not work well. It loses 10db when you use the bypass feature due to you are turning the preamp off to use it this way.  I will be upgrading to the Ayre 5 series separates but my existing system is so good I am going to keep it for another room after I get my Ayre components which has HT Bypass and works perfect.  I know the best sound you can get for 2 channel is not having your HT being connected to your two channel at all. My system sounds really good even though it is all hooked up together.  You will have to decide what is important to you. 95% of the time the room is 2 channel only. My music system has gone from Meh to holy &?!@ over the past couple years. I just added the JL Audio CR1 crossover with two F110 subs. After I get the Ayre gear I should be done with the base of the system. Seriously the Emotiva Preamp is worth it all day long. If you want an integrated amp then the Parasound Hint 6 is one of the best values out their and it has a DAC and Subwoofer control on the remote. Except for the Emotiva the rest of the gear in this post can be bought from this store in the Chicagoland area:
they have a try before you buy. Right now I am demoing so of the IsoAcoustic gear. This stuff is really amazing. Townshend stuff for isolation is great too. I would like to try that gear too. I hope this helped. 

I suspect the impact digital processing in the next decade or so will make multichannel considerably more of a 'player' to the SOTA enthusiast....not HT as we experience it, but more 'immersive'; the club in your space, concert hall acoustics replicated, the outdoor 'indoors'...

Keep listening, and we'll hear what happens....;)
It is a matter of simple logic to prove a surround system will never outperform stereo. Fact: better components cost more. Fact: no one has infinite money. Therefore, for however much money you have it will buy better components the fewer of them there are to buy.

Surround components never can be anything but equal to stereo, for the simple fact whatever technology is used in surround can be used in stereo- but not the other way around.

So it does not matter whether you have $5k or $50k, or $500k- or $5M. Divided into two speakers buys better sounding speakers than divided into 5.1 or 7.2 or whatever. Same for amps, cables, everything.

Quality rules. Surround sucks. Simple as that.
The most musical fidelit amplifiers has a pass through that's the best option. Intergrated with the Denon 3700.
Nice try. But I still have to give the nod to all your base are belong to us.
My point is that one can assemble a 2-channel setup of choice and if that setup includes a preamp with a by-pass input, it can also serve as the front LR for a surround setup without doing harm to stereo performance. I assembled a stereo setup comprised of an Ayre QX-5 Twenty Roon endpoint, Ayre DX-5 DSD disc player, Ayre P-5xe phonostage, Ayre KX-5 Twenty preamp, and VX-5 Twenty amp using balanced connections. Only later did I add balanced input from a Bryston SP3 processor. I dispute the contention that just connecting the SP3 to the KX-5 harms stereo quality. I don’t perceive any degradation, and I’ve done a lot of listening in a psychoacoutics lab. To address another objection, if one is inclined to allocate all available funds to a stereo setup, then obviously anything that diverts funds reduces funds available for stereo. I’m not so inclined.
For your information. I currently have a Lyngdorf headed my way. The 8805 Marantz I’m using is headed to my Sons, but I have a new, sealed, in the box Lexicon MC-10 that I purchased and before taking out of the box moved on to this Lyngdorf. I wanted to try the Lexicon because of Dirac Room Correction. I’m selling it for 2800, which is severely discounted. I’m just looking to move it .. Here is the review ..
How do you like being told surround is crap?

An irrefutable statement like that is unhinged.

Sure, not everyone is going to like home theatre, especially those trapped in the stereo past from last century, but the insistence is dreadful.

Comes across as a god statement.
How many movie theaters have sound only coming from the front?  Not sure what else there is to argue about. 
That's just plain stupid.

Home theaters are based around Dolby surround and any decent modern movie theater should be the same.
An economical way to give surround sound a try is to get the old Dynaco Quadaptor. You hook it up to your power amp's binding posts, and it creates a left minus right (L - R) signal, which is sent to a rear channel amp and speakers. The L - R signal simulates the random phase information contained in recordings made in large spaces (cathedrals, music halls, auditoriums, etc.), primarily in recordings of large ensembles (orchestras, choirs). In addition, some such recordings already contain out-of-phase information.

The Angstrom 200 I mentioned earlier contains L - R circuitry---along with a delay, as well as more sophisticated processing. The 200 also contains a decent DAC and analogue pre-amp. All from the fertile mind of Mike Moffat, and built like a tank (in the "horrible" State of California ;-) .
I have separate audio and video systems (the main speakers are shared and I just swap the speaker cables from one power amp to another).

I have a fairly decent Marantz AV preamp and have listened to stereo through it. It is pretty decent but it still isn't up to what my stereo only system can put through the same speakers.

Assess what your priorities are and go with your ears.
     For general principles, stay away from Lexicon.  Thy buy other stuff and re-box it for a much higher price:  Literally!   They took a $500 OPPO and put the whole thing, cabinet and all, into a pretty aluminum case, then charged $2500 for it.
I use a McIntosh MX123 pre-amp / surround processor with a BAT VK6200 amplifier. The processor selects the outputs according to the source and number of channels input. When I watch movies it’s surround sound, when I listen to music the system works in stereo. The BAT amplifier is really six, 180 watt, individual, independent, single-channel amplifiers in a card cage chassis. But, I’m satisfied with a mid-fi system. If you don’t need to play the extreme end of the audio world games, you can find a quite satisfying middle ground that will work for both video and music without needing separate systems. I know, on this website it’s total heresy...but someone had to inject a bit of sanity into the all-or-nothing approach to audio...
buckhorn_cortez that seems like a terrific system.

I just don't understand why all multi channel systems have been strangely lumped together and classified as crap. Persoanlly I believe they can be fantastic when setup correctly and it is indeed the statement that is crap.

How do you find the Audyssey? Mine sounds best when I limit correction to below 500Hz on all channels. 
 you can find a quite satisfying middle ground that will work for both video and music without needing separate systems. 
Sure, but you can also have an even more satisfying system that gives you the best of both worlds in one system, if only you knew what you were doing. 
I just don't understand why all multi channel systems have been strangely lumped together and classified as crap.
They’re not crap, but if you really care about better 2-channel sound reproduction there are compromises multichannel processors make that undermine achieving that end.  If you’re happy with the stereo performance of an AVP or AVR then rock on and it’s all good.  But if you’re looking to maximize 2-channel performance those compromises can be unacceptable, and for those people who can’t have two separate systems there is a viable alternative without having to compromise.  All depends on what your end goals are. 

So what are the compromises multichannel processors make that undermine achieving that end?

Surround processing is exceptionally suspectible to EMI and it is not all uncommon to see huge transformers so close they contaminate the process.

The best solution is separate power supplies, but that's an impossibility that'll never happen.
How do you find the Audyssey? Mine sounds best when I limit correction to below 500Hz on all channels.
I have an open floorplan so there are no walls between the living area and kitchen, with a large opening into a transition space to the other side of the house. The acoustic space is tall (12 feet) and large counting the kitchen. The rear surround speaker placement is limited to specific locations. The Audyssey system has made it possible to tune the surround system for better surround sound. It is far more balanced than it was with a previous surround processor that did not have that function. Compared to no Audyssey processing, there is an easily identified audible improvement.

Sure, but you can also have an even more satisfying system that gives you the best of both worlds in one system, if only you knew what you were doing.

Admittedly, I obviously have no idea what I’m doing. However, I’m satisfied with the results of my ignorance since I can’t hear the difference in fuse direction, am not concerned about the "blackness" of my system (whatever that is). I’m also convinced that people who use music to listen to their components in the belief they can buy and confect a system that will give them "realistic" sound reproduction are delusional...
So what are the compromises multichannel processors make that undermine achieving that end?
Where to start? Ok, noise is a good one. Having the delicate stereo signal in the same proximity to all the noisy digital processing, etc. going on in an AVP is to say the least suboptimal. Then there’s cost. If you’re selling a $6k AVP, how much of the parts cost goes to the stereo preamp and how much to the processing, other channels, etc.? Answer: not much. Of course, this includes the pivotal power supply that if not shared with the AVP is usually specified to meet a price point rather than for better sound. So, putting a good stereo preamp in an AVP would raise the cost to the point where most people looking for a multipurpose system would balk. There are some very good AVPs out there, but now you’re looking at >$10k, and what are the odds the preamp section in those AVPs is a good match for both your tastes and the rest of your other prized stereo components? Good luck with that one. Speaking of power supplies...
The best solution is separate power supplies, but that’s an impossibility that’ll never happen.
Which brings us back to “if you only knew what you were doing.” Given your arrogance I’m not inclined to waste the time explaining it here (maybe another more charitable member will), but it’s absolutely possible.
Admittedly, I obviously have no idea what I’m doing. However, I’m satisfied with the results of my ignorance...people who use music to listen to their components in the belief they can buy and confect a system that will give them "realistic" sound reproduction are delusional...
I agree wholeheartedly you obviously have no idea what you’re doing, and that’s absolutely fine if you’re “satisfied” with your results. You are the reason I included “If you’re happy with the stereo performance of an AVP or AVR then rock on and it’s all good” in my prior post. But if you think “realistic” sound is a pipe dream then it’s you who are delusional and you really need to go listen to what a really good 2-channel system is capable of because a truly good one can drop your jaw to the ground. But ignorance can be bliss — I’ll give you that.

Subaudible background noise? Now that sounds like an ASR obsession, which is obsessively pedantic and has virtually nothing to do with sound quality.

The sound from all channels must arrive with perfect timing. If not... Well I'm sure it doesn't take much imagination... (Perhaps this failing is the reason they have been systematically labelled as crap. If timing is out, they do sound like crap.)

Disregard automatically determined speaker distances and correctly set them. Ideally use a laser range finder to get precise measurements.

Naturally it goes without saying levels must be accurately set by fine tuning the automatically calculated assumptions.
Is it just me, or do others physically laugh out loud when when they read a comment by a narrow minded foolish biggot who makes rediculous assumptions regarding knowledge and experience to prove they must be superior? 
No, what’s funny is when someone obviously doesn’t know what they’re talking about and blatantly flaunts it in front of people who do.  Joke’s on you dude.