Center Channel recommendation for RS722s

[alexghanotakis]

Hi All,

I purchased the RS722s a few years back (much better deal back then) in large part due to feedback from folks on the forum. The speakers are awesome and I have really enjoyed them. I am now looking to use them in a 3.1 (if not 5.1) Home Theater set up. I would like the Center Channel to match the mains (RS722). In reading other posts it sounds like the RS722 is not ideal for use as a CC speaker as it is not designed to be positioned horizontally. Got a couple of questions. Any and all feedback would be much appreciated.

1) In one of the product Q&As PE recommends it is a good option for CC in Home Theater set up? Did something change over the past few years?

2) Is there something that I can do to the RS722 (for example tweak the XO) to make it work as a CC.

3) Is anyone aware of an existing CC design that uses the Tweeter (RS28A-4 1-1/8" Aluminum Dome Tweeter) and the woofers (RS180S-8 7" Aluminum Woofer) used in the RS722?

4) Is anyone aware of a design that does not use the Dayton Woofers and Tweeter but would be a good match?

Thanks in advance!

Alex

[rpb]

Re: Center Channel recommendation for RS722s

How much room do you have for the center? Will it be in a cabinet?

[alexghanotakis]

Re: Center Channel recommendation for RS722s

My thought was to use existing cabinet, place speaker on cabinet and rest Panasonic plasma TV on top of speaker.

However I am flexible and would rather find the right CC and then worry about TV stand, etc....

[djg]

Re: Center Channel recommendation for RS722s

These all use the same drivers and cabinet as the 722s. The diysoundgroup kit is of Jeff Bagby's design. If you can't make a cabinet, all could be made from a 722 kit by using different crossover components.

http://www.rjbaudio.com/RS180MTM/rs180-rs28-mtm.html

http://techtalk.parts-express.com/showthread.php?223870-My-RS180-MTM-Design

http://www.diysoundgroup.com/speaker-kits/denham/denham-kit.html

[jhollander]

Re: Center Channel recommendation for RS722s

I'm curious what post say the RS722, aka Dr. K's would not work horizontally as a center?

[alexghanotakis]

Re: Center Channel recommendation for RS722s

See thread below

http://techtalk.parts-express.com/showthread.php?203890-a-good-center-kit&highlight=RS722

[jhollander]

Re: Center Channel recommendation for RS722s

OK thanks. The other toppled MTM designs referenced by djg above the RS722s will perform similarly as a center. They all have a x-o point close to 1,500 Hz which will help with off axis performance. A stacked TM with flanking woofers would be even better (WT/MW).

Unless you plan to listen more than 60 degrees off the center line I doubt you can hear a difference with the toppled RS722s. As you have them give is a try, turn one on it's side then keeping moving off axis until you can hear a difference between straight on and off axis.

[alexghanotakis]

Re: Center Channel recommendation for RS722s

Thanks John.

How many degrees off center could I expect to get from the 3 MTMs found on the links provided above if I should get about 60 degrees from PE MTMs?

Also, got a good design for the WT/MW that you mentioned above?

Thanks

[djg]

Re: Center Channel recommendation for RS722s

Look at the center channel design for this. Scroll down a bit. It uses the same woofers, with different PE brand mid and tweeter. It fits sealed in the same PE cab as the 722, or vented in a wider cab. It is a 3 way WTMW. Designer is well known, never heard it myself. I have built three other Zaph designs.

http://zaphaudio.com/ZDT3.5.html

[jhollander]

Re: Center Channel recommendation for RS722s

How many degrees off center could I expect to get from the 3 MTMs found on the links provided above if I should get about 60 degrees from PE MTMs?

I'd say close to the same. One important note is that most of the speakers above are designed for placement on a stand. Placing them on a shelf or against the wall can make the bass sound muddy. You can set you AVR to small to solve the problem or look for a speaker designed as a center.

The Zaph designs (linked above) are good. The Statements is good if you can fit it http://speakerdesignworks.com/Statem...r_Channel.html

There are probably others.

[fbov]

Re: Center Channel recommendation for RS722s

...1) In one of the product Q&As PE recommends it is a good option for CC in Home Theater set up? Did something change over the past few years?

No, nothing changed but the wind direction... the pursuit of perfection has become more important. In many cases, it's a good option. In yours, it's an excellent option, as you have the speakers. Try it and see if you retain dialog intelligibility when a 722 is used as a CC (for test purposes, as perhaps the only speaker?).

Listening at speaker level from the floor, move around the room. On-axis should be very similar to your stereo usage, and there should be little change as you start to move off axis. As you get farther off-axis, mid-range frequencies should drop in level, while bass and treble remain substantially unchanged. Dialog intelligibility should suffer; it should get harder to understand what's being said.

If you don't hear the mid-range "hole" and have no issues understanding what folks are saying, you may not experience the downside of this alternative.

2) Is there something that I can do to the RS722 (for example tweak the XO) to make it work as a CC.

No. The issue results from the distance separating the two RS180s, and the crossover frequency. To fix the former, you can use a smaller tweeter. Select the tweeter wisely, and you can also lower the crossover frequency. The price is higher, of course...

3) Is anyone aware of an existing CC design that uses the Tweeter (RS28A-4 1-1/8" Aluminum Dome Tweeter) and the woofers (RS180S-8 7" Aluminum Woofer) used in the RS722?

That's the sideways RS722. To improve on that design, you need a smaller tweeter that crosses lower. A better starting point would be a 3-way (WTMW) with tweeter above the mid, but they tend to be wider, or use smaller drivers.

4) Is anyone aware of a design that does not use the Dayton Woofers and Tweeter but would be a good match?

Lots of them, but no MTM that's smaller/narrower and has this much capability.

These all use the same drivers and cabinet as the 722s. ....

I think there are now 7 crossover designs based on RS180/RS28a with a 12" mid spacing, so no fundamental change in the issue.

Here's the RS MTM family I built, Natalie P crossover from Jon Marsh, paired with the Modula MTM CC from his Modula family. One nice thing about this family is that Jon not only included high/low end versions, based on the tweeter, he also provides on-wall crossover options for the freestanding designs.

This last bit is important because if you put your CC under the TV, it's likely you'll want to use an in-wall crossover. I found the freestanding crossover to be very boomy - as it should be - due to my placement requirements.

If the Modula MTM CC sounds interesting, be aware that the original tweeter is NLA, but there is a drop-in replacement. Also be prepared for a large, complex and relatively expensive crossover. My CC was $400 in parts, same as a pair of NatPs. It was my fifth CC configuration, and the last.

It's also one of the few changes that the wife not only noticed, but felt was a real improvement.

Finally, I used designs from a single designer. I trust his ear to voice the speakers consistently. The Scan-Speak D3004/602010 tweeter in the CC was the only driver difference. That won't be the case with any CC you pair with the RS722s, except a toppled RS722.

Have fun,
Frank

[rpb]

Re: Center Channel recommendation for RS722s

My thought was to use existing cabinet, place speaker on cabinet and rest Panasonic plasma TV on top of speaker.

However I am flexible and would rather find the right CC and then worry about TV stand, etc....

I'm sure there will be some strong opinions voiced about center channel speakers. If it was me, I'd prefer a tweeter above the woofer(s). If you want to shake the room, and want a high power center, then the ideal design may be something of a compromise. If your main objective is to have good dialog at 45 degrees off axis, I'd maybe consider a 2-way with a 5.25" or 6.5" woofer. If you have plenty of room for a tall speaker, a tww with 5.25" woofers, or 6.5". Your tv screen, and possibly your cabinet will affect the frequency response, and tonal balance of the center. A while back, I was contemplating what I would build if I had a setup like a friend of mine has, which sounds like it's about the same as yours. I think that a basic 2-way would be the easiest to voice. With a mtm, the tweeter level may need to be louder than the x-over will allow. The same issue could arise with a tww, depending on the drivers used. If you use the same drivers as your mains, but use only one woofer, the tweeter can easily be adjusted louder. You could use a different woofer than your mains, but I'd recommend using the same RS28a, and the same x-over point and slopes as your mains. Why not, it's a good tweeter for crossing low. However, your center may need more output in the mids, and high frequency range than your mains due to the effect of the tv screen. If you need a physically small box, I like the sound of the Peerless 830874 6.5" drivers that I've been playing with lately. They seem to have a very natural sound on dialog. The box can be as small as .25 cu-ft or thereabouts, if needed. (I'd keep the center sealed.) If crossed at 1.5k to the RS28, I suspect that it would sound very nice once voiced.

[chrisn]

Re: Center Channel recommendation for RS722s

http://www.divine-audio.com/khancenter/

[alexghanotakis]

Re: Center Channel recommendation for RS722s

Hi All,

Thank you so much for your input and feedback. Lots of great info. Still haven't decided what I am going to do regarding center channel / HT however in the near term I am going modify my RS722s with the Jeff Bagsby crossover and go from there.

[---k---]

Re: Center Channel recommendation for RS722s

http://www.divine-audio.com/khancenter/

Yeah! That one. ;)