adding center speaker to existing stereo system

@tls49 , it looks like you might be able to provide me the exact advice I’m looking for! I hope there’s no strong etiquette here against posting essentially the same question in two threads because I just posted basically the same question in the OPPO thread.

I love your advice that a phantom center is better than a mismatched center because even a B&W Nautilus center isn’t going to really match my N801’s, especially because I’m not going to match my Levinson 333 amp for it.

You’re suggesting adding rear channels. Do you recommend only rears, rears and sides, or just sides? In other words, I could add two or four speakers to my room for surround effects. If it’s cleanest just to add two, then which two? How do you recommend doing this? I like the idea of using the OPPO 105D instead of my PS Audio Stellar Gain Cell DAC if it sounds "good enough." As long as it supports a phantom center, and it appears that it does from the manual I found online, and as long as I can use the XLR outputs as the front two channels for surround config, then I would appear to have the functionality I’m looking for from this piece.

Thank you for your feedback!

@imhififan - I suppose you could use a RCA to XLR cable, but it's really not the right way to do it. On this RCA to XLR cables, the negative polarity signal wire on the XLR is connected to the shield/ground on the RCA.  You really should have a Jensen transformer converter box here to convert the RCA single ended to a true balanced signal if you want to do it correctly.

Just picked up on this thread.  I'm was a Jim Bongiorno fan before his passing.  He tackled this deeper than anyone else that I've seen.  This is a terrific item, take a look. 
https://www.sst.audio/new-products/trinaural-processor

@auxinput, why not a pair of rca to xlr cable with xlr passive preamp or switcher for Option #1?

"I think the idea that you should ONLY add a matched center is unnecessarily puritanical, and my own listening tests have shown to me that adding a different center, when done right, is a big improvement over a phantom center. Have you done this experiment?"

Sorry Erik, but again I must respectfully disagree, and yes, have done the experiment. When evaluating a client’s existing system, I would have them compare the way it was to using phantom center. Never had anyone with a mismatched center to say it sounded better and some with timbre matched even like phantom better. Dialogue could be adjusted louder with a mismatched center but the entire front image and overall sound was worse compared to using phantom. This definitely prompted many to upgrade and get as close as possible to 3 identical speakers on the front.

And yes, I have experience with room correction and DSP. It can help a little, however it is not a magic bullet and can not make a mismatched center have the same tonal character of the L & R. If it was that magic bullet, you could take 2 different speakers and make it sound like a stereo pair. I don’t think so.

Yes, the center speaker plays dialogue, however it affects the entire front image and sometimes that dialogue can be produced by the center and a L or R speaker depending on where that person is located in the picture. With a stereo pair, a single front image is created, but when a center speaker is inserted, that entire front image becomes much more complex. 3 identical speakers and that works easily with tonal character remaining consistent across the front. A mismatched center can provide louder dialogue, but at the expense of severely degrading the front image and tonal character within the image. I have heard many systems in which a vehicle moving across the picture sounds normal on each side, but much smaller or different at the center position. Now if the OP needs a center for off axis listening, that’s a different issue. I did reference that in my first post, however he has not responded.

Sound bar? Surely you can’t mean to use it with his current system. What a mess that would be. Assuming not, and using it alone compared to his current system, and I’ve got to assume this added TV is between the L & R speakers, no brainier, I’ll take the system.

Again, I must stay with my original recommendation that if he does anything, it should be rear speakers to get room filling effects and forget the center unless there is an off axis listening issue.

So Erik, sorry to say that it looks like the only thing we will agree on is the fact that we disagree, and that's ok, as everyone is certainly entitled to their opinions. Also, keep in mind that I speak from experience with many clients and it’s not just "my" experience.

good point erik.

aux - You are not wrong ----

but what a mess we get into. That's why I suggested a sound bar instead. Simple, and good enough for a listener who wants to watch movies occasionally. 

Hello all, if you have read czechu82’s post, you will see that he just wants to add a center channel so that he can watch tv/movies from time to time.  He does not want to use the center channel to add to the music score.  In this situation, adding a receiver could be a good solution if he doesn’t care as much about tv/movie sound quality.  However, like everyone has agreed, the center speaker should match as closely as possible to the left/right speakers.

@czech82 – I see that you do not have a preamp listed in your system, so I am assuming you are connecting the PS Audio Directstream DAC directly to the REF600M amplifiers.  If this is the case, you can add a receiver, but you need some sort of switching mechanism in the middle (such as a normal preamp or a passive preamp with at least two inputs).  Then make it into a “hybrid” system.

A passive preamp is the cheapest way to do this.  Just connect the PS Directstream and the new receiver to the inputs of the passive preamp.  Then connect the outputs of the passive preamp to the REF600M amplifiers.  You can run the passive preamp at full volume all the time since you are controlling volume from the Directstream or receiver.  Then just switch the passive preamp back and forth between the Directstream and the receiver to use as sources.  Khozmo and Goldpoint are two companies that make excellent passive preamps (in the $400 to $600 price range).  Alternatively, you can get the Goldpoint SW4 input switcher for $376 (does not include a volume control).  The only problem with passive preamp is that you are limited to RCA interconnects.  HT receiver will only have RCA outputs (they will never have XLR outputs) and the passive preamp CANNOT convert an RCA signal to a balanced XLR output.

If you want to use XLR for the Directstream and the REF600M amps, there are two other options. One option is that you will need to get some sort of active preamp that has both XLR and RCA inputs.  This needs to be a very high end and transparent preamp, such as the upper end Krell Illusion or Phantom, or something like an Ayre Acoustics preamp.  There’s a Krell Illusion II on audiogon for $3400, which is about the minimum I would recommend for a highly transparent preamp.  DO NOT get a Krell Phantom III  (only the I and II models are good).  Keep in mind that no preamp is truly transparent and it is going to add some sort of color or sonic signature anyways.

The other option is to get a fully balanced XLR passive or switcher, then get a HT Processor and a third REF600M amp (or equivalent).

So, three options:

 

Option #1:

Sonus Faber center speaker

Receiver

RCA passive preamp or switcher

3 sets of RCA interconnects

 

Option #2:

Sonus Faber center speaker

Receiver

High end preamp (Krell/Ayre)

2 sets of XLR interconnects

1 set of RCA interconnects

 

Option #3:

Sonus Faber center speaker

HT Processor

Monoblock amp (like REF600M)

XLR passive preamp or switcher

4 sets of XLR interconnects (one for center)

 

 

There is a fourth option, but it means spending a whole lot on a new HT processor that is at the level of a decent audiophile preamp and using that HT Processor as the “preamp” for the Directstream DAC.  Options could be Bryston SP, Classe SSP-800 or Krell Foundation.  All three of these have balanced XLR inputs and outputs and make decent preamps.  However, they are not going to be as good as a passive preamp or a Krell Illusion preamp.

 

So, Option #4:

Sonus Faber center speaker

Very good HT processor

Monoblock amp (like REF600M)

4 sets of XLR interconnects.

hi @tls49

My experience is that I used to work in making audio equipment for motion picture auditoriums, until Dolby Digital came out, and make my own loudspeakers, on top of being a hobbyist for decades.

I think that while having identical L, R and C speakers is an ideal, it is not the ONLY way to improve sound quality. Well matched speakers, especially with room correction can be a real benefit to dialogue. I know this from personal experience using very different speakers I have made, along with DSP. Would I compare this setup to Spielberg’s? Of course not. That was not the point I wanted to make to the OP.

My first post was not about whether to use identical speakers and amps, but was about how HRTF (head related transfer functions) affect our listening, and why a center channel can enhance the experience more than obvious compared to a phantom center. I really did not argue about how close a match speakers should be. That was all you.

I think the idea that you should ONLY add a matched center is unnecessarily puritanical, and my own listening tests have shown to me that adding a different center, when done right, is a big improvement over a phantom center. Have you done this experiment? I can tell you in my case the sound was absolutely seamless.

Best,

Erik

tls49 is right. it is pointless to add a speaker different in brand etc from side spkrs if you are going for high end sound. i did it, trust me.

Erik, you certainly have the right to your opinion, however, I only agree with it for one particular scenario.

I worked in the A/V industry for ~25 years, mainly dealing with mid to upscale products. The latter 15 years was spent with increasing time designing custom home theater and supervising the install. No doubt I have listened to more and a wider variety of home theater than the majority of the people here. From that experience, to agree with your comment, the center speaker would need to be identical to the L & R, not just timbre matched, but identical. Also, it would need to be driven by an amp channel identical to the L & R. The closest center speaker to his L & R is the Olympica Center, however since the OP is talking an A/V receiver for the processing and power, that just doesn't make good sense. Then use a speaker more suited for the A/V receiver, and that will do more harm than good compared to phantom center. Now if he wants to get the Olympica Center, another REF600M monoblock, and a nice processor, that would likely work ok, otherwise, I'll stay with my original recommendation.

Some of the best sounding theaters I did, regardless of price, used all identical speakers with high quality identical amp channels.

HI @tls49  You make a good argument, but it's not complete.

Turns out, a center channel can really be helpful. Have you ever noticed a change in tone when an instrument pans from left to center? It turns out that right in the center your head plays a part in cancelling some of the sound. Early recordings were actually 3 channel, and man, do they sound good. :) 

So, for movies and dialogue especially, a center channel will sound somewhat better than a L and R phantom. 

Best,


E

I submit having a preamp that has HT bypass is the best way to combine 2-channel with a surround system. When I'm listening to music my surround components are off. When I'm watching a movie I use my preamp's HT bypass. My 2-channel amp continues to drive my fronts.  I turn on my Marantz AV processor, ATI 3-channel amp and OPPO 203. My 3-channel amp drives my center and rear speakers. 

you should just add 2 more speakers for the left and right rear for your system. this is how my setup is.

Obviously you are sitting in the center between your current speakers for music. Assuming you sit in that same position for movies, what are you missing or what are you hoping to gain? I'm thinking it should sound good. If I were to add anything for movies, the first thing would be rear channels for room filling effects.

For simplicity, I really think you should consider a sound bar instead. 

i use a center speaker in a hafler array. i take a headphone out from my DAC and put it in the mono input of a Yamaha DX7 powered speaker...
... it sounds nice. the DX7 is a better speaker than my LSR305s, but I do lose some spacial-stereo effect. I angle the center channel at opposing walls, the ceiling and also conventionally centered. try it.