# Kind of unusual setup...



## premiumplus (Apr 29, 2008)

For my birthday I am upgrading my system. I just got a 75" 4K LG UHDTV, and I have some Bose surround speakers for the sides and back. I want to use my 2 channel Hi-Fi system for the front two channels. It's a very high grade component stereo with an electronic low pass bi-amp setup of Dahlquist DQ-10's, DQ-1W Subs, and SAE preamp. The power amps are WOPL Phase Linear 700b amps, totally rebuilt with new driver boards and output protection. The amps are putting out an honest 475+ watts RMS per channel, x4. It sounds and feels like a live concert.

For video Blu-Ray discs I've got an Oppo BDP-105 that's great, and I've got a good, fast wi-fi system in the house.

So what I need is a recommendation for a 7.1 Surround Receiver that has a full range stereo output for the Left and Right channels, that will drive my high end stereo for the main channels. I won't be needing a separate subwoofer, because the primary stereo system sounds so huge and lifelike. I just want great surround sound.

I'm looking at a Yamaha RX-V685 receiver which looks like it would do what I need. I'm seeking your expert opinion of this receiver or a recommendation of another one that will accomplish my goals.

Thanks, fellas (and ladies!)


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## premiumplus (Apr 29, 2008)

Nobody?


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## Hornblower64 (Jun 10, 2012)

The Yamaha receiver you mentioned should do what you want. Use the pre out (line level) outputs to feed an aux. input on your SAE preamp. You may want to mark where unity gain is on your preamplifiers volume knob with a small arrow or triangle sticker, so you can keep relative volume levels consistent with the other channels. This gain will be dependent on the overall electronic system gain, and the efficiency of the speakers. Some newer preamplifiers have a unity gain (home theater bypass) input to make this easier.

What will you be using for a center channel? It should match the character of the L/R speakers, and be of similar quality. Typical video surround mixes require the center channel to preserve the balance between dialogue, soundtrack, and effects.


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## Mazza (Jun 27, 2010)

Not really unusual. I have a great old Yamaha AX-570 integrated connected to the pre-outs of my Onkyo receiver. I do this cos for two channel it is best sounding/simpler.

I have my CD analogue outputs and a Chromecast Audio connected to the AX-570 so I can bypass all the HT paraphernalia.

Assuming you have outboard subs placed around your room then for best integration I still employ a high pass filter on my mains despite these being very capable full range speakers in their own right. In my room that just seems to give the best result, in my room with my system. Naturally yours will be an entirely different situation. 

Go with what sounds/measures best!


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## premiumplus (Apr 29, 2008)

Being a very old school guy and new to setting up multi channel home theater systems, (and probably wrongly assuming that the center channel info would be mixed from the two front L/R speakers?) I hadn't considered the center channel to be that vital. What does the center channel usually contain that wouldn't be covered in the front L/R speakers?
If it's going to make high demands on the speaker, I'll ditch the little Bose satellite speaker and use a JBL L36 speaker. It's a 3 way, 10" woofer old stereo speaker. I recently rebuilt a pair, they're great classic speakers.


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## Mazza (Jun 27, 2010)

I am not a fan of center channel speakers, their horizontal driver arrangement is highly sub-optimal.

Audioholics did I good write up on the matter.

I've not been using mine for some time and don't miss it. When you switch off your center channel in your receiver or pre/pro it will mix the center channel information into the left and right. 

I'm not too fussy about surrounds. I use a generic but reasonable quality in ceiling two way speaker system for spousal approval purposes. These work great. I'm sure you will find the Bose are a good way to start, why not try them. 

I'm sure the JBL's are waaaaay better (I love JBL) so if it were me I'd try them out too. The compromise with the JBL might be the wife nagging you to put the little Bose back up? Like all things audio/evetythinig the sky is then the limit.

Going back to your original question, any receiver with pre-outs will work. You just need to set your left and right front speakers in the receivers menu to full range. Connect you preamp to the receivers front left and right pre-outs and you are good to go. 

Happily the Yamaha's volume at 12 o'clock matches the level of my receivers speaker level outputs so it is easy to level match across the two amps.

Good luck.


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## Hornblower64 (Jun 10, 2012)

Yes, the horizontal center channel that is typically found is done for marketing reasons, but my experience has been that the 2ch. mix down can result in murky dialogue, and that decisions made by the mix engineer can produce wildly variable results. 

And if the dialogue is primarily in the center, then you can affect the balance of elements in the soundtrack by changing the center level.

I prefer L/C/R speakers to be identical.


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## premiumplus (Apr 29, 2008)

Mazza said:


> I am not a fan of center channel speakers, their horizontal driver arrangement is highly sub-optimal.
> 
> Audioholics did I good write up on the matter.
> 
> ...


Thanks, this is exactly the info I needed. I just ordered the Yamaha last night and I'm looking forward to getting proper surround sound. The Kenwood VR-6070 I've got is so ancient that it doesn't even have HDMI inputs/outputs. I hope that the Yamaha RX-V685 will mix the center channel in like you say, because the room is different in that the wall the TV monitor is on has french doors in the middle of it, going into my music studio. So there's no good place to install a center speaker...I have been hiding one of the little Bose cubes in my left channel Dahlquist cab and it's close to center but not ideal.
I appreciate the support, fellas. Thanks.


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## powerlifter405 (Jul 28, 2013)

Hornblower64 said:


> Yes, the horizontal center channel that is typically found is done for marketing reasons, but my experience has been that the 2ch. mix down can result in murky dialogue, and that decisions made by the mix engineer can produce wildly variable results.
> 
> And if the dialogue is primarily in the center, then you can affect the balance of elements in the soundtrack by changing the center level.
> 
> I prefer L/C/R speakers to be identical.


We recently moved and during the transition/setup phase I ran everything 2.1 and the dialogue was always lacking when we watched movies. I'm now running my Chane A1 center again and dialogue intelligibility has improved dramatically.


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## willis7469 (Jan 31, 2014)

premiumplus said:


> Being a very old school guy and new to setting up multi channel home theater systems, (and probably wrongly assuming that the center channel info would be mixed from the two front L/R speakers?) I hadn't considered the center channel to be that vital. What does the center channel usually contain that wouldn't be covered in the front L/R speakers?
> If it's going to make high demands on the speaker, I'll ditch the little Bose satellite speaker and use a JBL L36 speaker. It's a 3 way, 10" woofer old stereo speaker. I recently rebuilt a pair, they're great classic speakers.




The center is mainly responsible for carrying dialog but also a lot of other screen info. IMO, phantom center is always comprised and if you’re off axis(like anybody NOT in the sweet spot), phantom image collapses. Find a good quality CC speaker. The JBL you mentioned could work, but imo it’s important to match the front 3 at least as much as you can, ideally 3 of the same, towers or , or at least the matching in the same series. The JBL’s(assuming you have a pair) would likely make a good surround pair. FWIW, my whole bed layer is JBL. 
Also, toss the bose cubes out onto the sidewalk with a free sign. They will only hold back the rest of the system. 
I tried to find out some more information on your mains as whenever someone says “I don’t need a subwoofer”, it’s always an interesting conversation. In any case, I could not find anything definitive. Do you have any links to literature, or pics?


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## theJman (Mar 3, 2012)

Mazza said:


> I am not a fan of center channel speakers, their horizontal driver arrangement is highly sub-optimal.


I'm not sure that's necessarily the case; while horizontal alignment does present some challenges, "highly" sub-optimal seems like a bit of an overstatement. If it was really all that bad why does virtually every speaker manufacturer on the planet make scores of different models around the same alignment? Logic suggests there would be more than a handful of outliers producing centers with something 'better', if for no other reason than to tout their superiority. Packaging does play a part of course - after all, how many people have the ability to use a tower for a center? - but that certainly isn't the only reason. What's truly flawed are phantom centers. Given the aesthetic benefits of using no center you would think that option would be chosen by more people, but one listen and it quickly becomes apparent how bad that arrangement sounds. Despite the potential difficulties that horizontal alignments might cause they seem to be used 1000x more than phantoms, so there's got to be something involved.


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## Da Wiz (May 8, 2019)

horizontal drivers are NOT the problem. The problemis having a midrange driver on each side of a tweeter laid out horizontally with the 2 midrange drivers outputting the same sound over the same frequency range. 

There are several simple ways to eliminate the problem with comb filtering when there are midrange drivers on both sides of a tweeter.

Quite a few models avoid the whole comb filtering issue by removing midrange audio from one of the 2 mid-woofers by employing separate crossovers for the 2 mid-woofers. Example: Tweeter operates from 2500-20,000. One midwoofer operates from 2500 Hz down to, say 50 Hz. The crossover for the second midwoofer operates over 40 Hz to 150 Hz. Problem 100% solved by not allowing midrange frequencies to be reproduced by both woofers.

Another design choice also stops the comb filtering by placing a tweeter above a midrange driver in the center of the center channel speaker with a woofer to each side. Since the woofers do not reproduce midrange frequencies, there is no comb filtering issue.

Finally, if you have a center channel with a center tweeter flanked by midwoofers and the comb filtering bothers you, rotate the center channel speaker 90 degrees so it is vertical. 

Comb filtering changes sound in the horizontal direstion as you move left/right of center when the MTM driver arrangement is horizontal while verticle dispersion is good. Rotate the center 90 degrees so the drivers are vertical, you get smooth horizontal dispersion and comb filtering in the vertical axis that can change the sound as you stand or sit.

So like everything else in home theater... every design has strengths and weaknesses. You typically cannot dismiss a product category without understanding the background.


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## premiumplus (Apr 29, 2008)

Good discussion, and I agree about the Bose cubes (Bose: Buy Other Sound Equipment). I'll try to dig up some info about the Dahlquist bi-amp system. Thank you, fellas. I've got a lot to learn about home theater. I'm solid in two channel stereo and very solid in guitars, tube guitar amps, and effects, but I'm new to home theater.


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## BP1Fanatic (Mar 28, 2011)

Hornblower64 said:


> I prefer L/C/R speakers to be identical.


I agree!


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## willis7469 (Jan 31, 2014)

BP1Fanatic said:


> I agree!




Is that center behind the tv? Can’t imagine that works tonally or specially. I imagine like talking to someone with a plate in front of their mouth lol.


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## premiumplus (Apr 29, 2008)

willis7469 said:


> The center is mainly responsible for carrying dialog but also a lot of other screen info. IMO, phantom center is always comprised and if you’re off axis(like anybody NOT in the sweet spot), phantom image collapses. Find a good quality CC speaker. The JBL you mentioned could work, but imo it’s important to match the front 3 at least as much as you can, ideally 3 of the same, towers or , or at least the matching in the same series. The JBL’s(assuming you have a pair) would likely make a good surround pair. FWIW, my whole bed layer is JBL.
> Also, toss the bose cubes out onto the sidewalk with a free sign. They will only hold back the rest of the system.
> I tried to find out some more information on your mains as whenever someone says “I don’t need a subwoofer”, it’s always an interesting conversation. In any case, I could not find anything definitive. Do you have any links to literature, or pics?


Here's literature on the active crossover and subs: 
Crossover: https://www.hifiengine.com/manual_library/dahlquist/dq-lp1.shtml

Subwoofers: I couldn't find much info on the DQ-1W subwoofer. It's a 13" (right...not 12") driver in a sealed cabinet large enough to support the main DQ-10 Phased Array speakers.

System info: https://stereonomono.blogspot.com/2017/03/dahlquist-dq-10.html

They sound great bi-amped, and as I mention in the OP I'm driving them with two White Oak modified, completely rebuilt Phase Linear 700b amps. I got the Yamaha RX-V685 receiver up and running and it sounds GREAT through the L/R preamp outs to my main stereo system. I'm systematically replacing the Bose cube speakers...:wink2:


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## willis7469 (Jan 31, 2014)

premiumplus said:


> Here's literature on the active crossover and subs:
> 
> Crossover: https://www.hifiengine.com/manual_library/dahlquist/dq-lp1.shtml
> 
> ...




Cool. Will read. I totally get the “systematic” approach. Lol I think WAF is stupid, but we all have some if don’t we.


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## Hornblower64 (Jun 10, 2012)

I spotted a single DQ-10 on that auction site for $99. On the floor, tilted up, as a center channel? The bass balance will change slightly with it being closer to the floor, but that's easy to fix. Just a thought. The going price for DQ-10s seems to be $200-800/pr., depending on condition and demand at the moment, of course.


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## premiumplus (Apr 29, 2008)

Hornblower64 said:


> I spotted a single DQ-10 on that auction site for $99. On the floor, tilted up, as a center channel? The bass balance will change slightly with it being closer to the floor, but that's easy to fix. Just a thought. The going price for DQ-10s seems to be $200-800/pr., depending on condition and demand at the moment, of course.


Thanks for the tip, but I don't have room to put it in the middle of the other two DQ-10s. There are two French Doors that open to an adjoining room that I always leave open. So the TV is offset to the left a bit but even then it takes up half of one side of a door. Like I mentioned, it's an unusual room...So my center channel speaker sits behind the grill of the left hand DQ-10, which locates it slightly to the right of center in relation to the TV.
The Yamaha auto-EQ system reported back that I had out of phase issues with four of my speakers (And I checked their electrical phase prior to installation...they were all correctly phased); the left, center, right, and right surround. I reversed the phase on these and the Auto EQ checked out okay. So I must have phasing issues / comb filtering going on in this room. It's crazy. I wish there was a way I could show an overhead view of the walls and area coverage of the room, you'd laugh and say "Good luck, man!" 

I do have it sounding good right now, and when I kick on the main stereo for a movie it's really nice. I'm getting 116dB peaks at my couch, and it's clean too. A thunderclap sounds and feels like thunder overhead. Voices are natural, right inside my head. I'm pretty happy at this point but I've still got two Bose cubes to dispose of. Trying to figure a way to fit my JBL L-36 speakers in next to the huge Dahlquist systems.


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## BP1Fanatic (Mar 28, 2011)

willis7469 said:


> Is that center behind the tv? Can’t imagine that works tonally or specially. I imagine like talking to someone with a plate in front of their mouth lol.


2 speakers behind the tv and voices sound like they coming straight out the actors' or anouncers' mouths.


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## Mazza (Jun 27, 2010)

Da Wiz said:


> horizontal drivers are NOT the problem.




If one were to take a good quality two way with controlled directivity and lie it on its side, its off axis response will likely go from performing well over a 90 degree arc down to a 40 degree arc, or less depending on driver center to center spacing. 

Example - Klipsch RP-160M.....










Has nice horizontal polars (standing upright) 0-90 degrees off axis….










Dr Geddes polar of the same data....











Now if you were to lay that same speaker on its side (vertical polar) things start going astray.....











So, in this example, if you were to sit 20 degrees or more off axis from the RP-160M laying on its side, you should not expect a great performance from its horizontally arranged driver layout. Which is, of course, precisely why speakers are usually vertically arranged! :devil:

Now that may not be too much of a problem if you have a narrow room or you sit close to your center speaker.

Traditional center channel speakers however are highly sub optimal…. lddude:

*The folly of a horizontal centre channel speaker - RP-250C measurements* 

Unless they are arranged, at least in part, vertically.... *8008-Center mkII*

:grin2:


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