My center channel build

[MaverickLS7]

Hey everyone, just wanted to share my center channel modification. Quick note of my gear, I'm using the Klipsch Synergy III series as in F3's, B3's, and the C3. The C3 to me didn't bring enough depth in the movies and sounded.. I don't know how to explain it, but lack of fulfilling the center frame action of a movie. After all the center to me is very important and demands a lot. So.., I figured I'd make one consisting of 2 F3's combined. It's already up and running and I couldn't be happier. It performs exactly how I'd imagine it and gives me that depth I wanted. Pictures of the build are below, enjoy!

I might as well go into more detail on my system as well.
Yamaha RX-A3060 as receiver, powering surrounds L/R F3's, rears L/R F3's, and F/R L/R heights B3's.
Yamaha A-S501 external amps (x2) 1 for front L/R F3's. 1 for center F3's.
SVS SB1000 subwoofer (x2) front L/R.
Klipsch Sub10 subwoofer rear.
Epson 5030UB projector.
EliteScreens 110" screen.
PS3 music player/storage.
PS4 movies/games.

Ok, on with the pictures.

 

[rojo]

Wow, umm... well, it looks fancy. I wish you'd posted your intentions before doing that though. But if you're happy with the sound, then congrats on a nice looking mod.

 

[MaverickLS7]

Wow, umm... well, it looks fancy. I wish you'd posted your intentions before doing that though. But if you're happy with the sound, then congrats on a nice looking mod.

Thanks, but I don't fully understand "intentions", what do you mean? I just wanted to make something better while keeping the Synergy III series.

 

[rojo]

Thanks, but I don't fully understand "intentions", what do you mean? I just wanted to make something better while keeping the Synergy III series.

By intentions I mean your plans to create a center channel out of two tower speakers. But as I said, if you like how it sounds, then my concerns are for nothing.

 

[TLS Guy]

By intentions I mean your plans to create a center channel out of two tower speakers. But as I said, if you like how it sounds, then my concerns are for nothing.

Your reservations are justified. There are so many things wrong with the physics of that you just don't know where to begin. Certainly not a design to be recommended. But as you say if it keeps him happy fine!

 

[MaverickLS7]

Your reservations are justified. There are so many things wrong with the physics of that you just don't know where to begin. Certainly not a design to be recommended. But as you say if it keeps him happy fine!

Let's talk about it. What are your opinions and concerns? I can always learn more.

 

[lovinthehd]

I don't think I've seen a bi-bi-wireable speaker before. Nice handiwork on combining the boxes, tho.

 

[MaverickLS7]

I don't think I've seen a bi-bi-wireable speaker before. Nice handiwork on combining the boxes, tho.

I have center preout to external amp to L/R speakers acting as one.

 

[lovinthehd]

I have center preout to external amp to L/R speakers acting as one.

You mean your new center? or the L/R speakers? How exactly did you wire it up?

 

[MaverickLS7]

You mean your new center? or the L/R speakers? How exactly did you wire it up?

Center. Which is basically 2 floorstanding speakers together on its side. I didn't change the wiring inside, they're are still separate. So I ran a preout center channel from my receiver "1 signal" to splitter L/R to external amp. So now the external plays the same signal out its L/R terminals and that's how I have center hooked up. Sorry I'm not the best explaining things.

 

[TLS Guy]

Let's talk about it. What are your opinions and concerns? I can always learn more.

Essentially your problems can be put under two heading mainly. Severe lobing error and comb filtering.

Lets back up though and discuss your original problem. It is the function of the left and right speakers to produce a seamless sound stage. So it would seem these speakers were not. So your first approach should have been changing the front speakers. The current Klipsch speakers are not ones I hold in high regard.

In fact with good speakers it makes minimal difference whether the center is used or not. The BBC believe a center speaker is actually a detriment and do not ever record or include a center channel. I should say for the record that BBC engineers are among the most respected in the world. The BBC engineering department has a long a storied history.

So what is the purpose of the center channel Primarily it is a dialog channel to produce clear dialog and center it for all listeners. Good centers above all should be able to reproduce the human voice clearly and without coloration and without the need to artificially boost the level. This sounds simple but it is in fact a tall order.

Now when you lay a speaker on its side the dispersion is primarily in the horizontal plane and not the vertical which it should be. So most centers get off on the wrong foot before you start. The problem is it does not center dialog as much as it should and maximizes troublesome floor and ceiling reflections.

Now one tends to localize to the tweeter location, especially in center speakers. You have two tweeters far apart. So you have done the opposite of precise localization.

The next issue is that you have four drivers acting as a horizontal instead of a vertical line source. In addition you have frequencies up to 2000 Hz from four drivers. So here will be additions and subtractions at a host of frequencies dependent on driver spacing. This is what we call comb filtering. In addition the unit is so wide there is going to be a lot of interference between that center and the left and right main speakers. In a word your system has to be awash in comb filtering problems.

I have found that the best centers have a focused cone shaped response over just the listening area, to minimize interference between the center and left and right channels. This I think is the main objection of the BBC to center channel speakers.

In summary I think you went for the wrong target for you issue of lack of a wide and seamless front sound stage. So you now have a gigantic wide mono speaker across most of the sound stage and close, especially the tweeters to the right and left main speakers. This is certainly not something I would advocate.

 

[rojo]

Let's talk about it. What are your opinions and concerns? I can always learn more.

I'll second Dr. Carter's sentiment. Biggest concern is the layout of the drivers. Have a look at this page for a brief intro to center channel layouts. From that page:

... this type of design produces the worst lobing errors (especially the TMMMT version) of all four designs discussed here and thus results in the narrowest usable listening window.... We caution anyone considering a TMMT or TMMMT center channel if you're sitting anywhere but directly on-axis to the speaker.

And there are other problems. Those bass drivers were intended for a much larger cabinet. Using the same size vents in a smaller enclosure will alter the tuning of the cabinet. You've exchanged a ~10-inch wide baffle for one many times as wide, so there will be a hump in the response over a bigger part of the upper frequency bands where ever-wider wavelengths are reflected front by the speaker baffle. Normally this sort of thing is figured into the crossover with a clever crossover point, a resistor to bring the tweeter level down to match the mids (below the baffle step), a notch filter if needed -- basically lots of planning, conscientious design, measurements, blood, sweat, and tears. If you're using the stock crossover, it has no compensation for these changes. And there's also the comb filtering TLS Guy described from sympathetic additions and cancellations between the tweeters, giving you a response with spikes and dips like the teeth of a comb.

 

[MaverickLS7]

Great info guys! I read into some of that before I started, and honestly wasn't worried. I've conducted a few tests as well obviously, by itself, full range "large" just to see, with subs crossover 80 "small", and complete with all speakers in movies/music. It does very well and I wish someone of your knowledge and experience can check it out for yourself for live feedback. It doesn't sound to wide either and doesn't interfere with front towers. It brings a clearer/cleaner sound at low scenes and loud scenes and can handle all the action, unlike the c3 I had where it sounded cluttered and dialogue would get washed out.

 

[KenM10759]

Where are you located? If you're inviting people over to hear it that would be good to know.

 

[Grassy]

Great info guys! I read into some of that before I started, and honestly wasn't worried. I've conducted a few tests as well obviously, by itself, full range "large" just to see, with subs crossover 80 "small", and complete with all speakers in movies/music. It does very well and I wish someone of your knowledge and experience can check it out for yourself for live feedback. It doesn't sound to wide either and doesn't interfere with front towers. It brings a clearer/cleaner sound at low scenes and loud scenes and can handle all the action, unlike the c3 I had where it sounded cluttered and dialogue would get washed out.

That's what I am trying to achieve with my centre.Even though I love my speakers,the down side to my system is my centre channel speaker as it is never loud enough for me.Actually this thread has gave me some ideas.If there is anything I would change in my system it would be my centre channel.I was thinking on keeping my centre speaker box and changing my woofers and tweeter to a louder set and installing them in the box.Would that work?I know a lot off the centre volume comes down to the mix but at the same time I would think the quality of the speaker does matter to a degree.

 

[rojo]

That's what I am trying to achieve with my centre.Even though I love my speakers,the down side to my system is my centre channel speaker as it is never loud enough for me.Actually this thread has gave me some ideas.If there is anything I would change in my system it would be my centre channel.I was thinking on keeping my centre speaker box and changing my woofers and tweeter to a louder set and installing them in the box.Would that work?I know a lot off the centre volume comes down to the mix but at the same time I would think the quality of the speaker does matter to a degree.

Ever measured the response of your current center channel? There could be a null in a critical range that makes dialogue difficult to understand without the center channel being cranked up. It could be that your center channel's crossover was designed to have the tweeter wired out of phase, but the assembler wired the tweet incorrectly causing a severe dip around the crossover point. Or maybe there's a lobing problem if you sit off-axis. Or maybe there's a placement issue causing a suckout. I see in your front stage photo that your center channel rests against the front wall. It's not rear ported is it? Anyway, measuring the response might help you solve this mystery.

I used to turn my previous center speaker up about 6 or 7dB louder than my mains for intelligibility. It also sounded boxy at times -- not often, but enough that I eventually upgraded. My current center is now about the same volume as my mains, because it's a better center and easier to understand dialog at lower levels.

But upgrading the center channel was not simply a matter of swapping out drivers in an existing cabinet. To answer your question:

I was thinking on keeping my centre speaker box and changing my woofers and tweeter to a louder set and installing them in the box. Would that work?

No. This is not a good idea at all. As I mentioned in post #12, there's a lot of knowledge, time, and effort that goes into designing a worthwhile center channel speaker; and replacing drivers based purely on their sensitivity is a recipe for disaster.

 

[Grassy]

Ever measured the response of your current center channel? There could be a null in a critical range that makes dialogue difficult to understand without the center channel being cranked up. It could be that your center channel's crossover was designed to have the tweeter wired out of phase, but the assembler wired the tweet incorrectly causing a severe dip around the crossover point. Or maybe there's a lobing problem if you sit off-axis. Or maybe there's a placement issue causing a suckout. I see in your front stage photo that your center channel rests against the front wall. It's not rear ported is it? Anyway, measuring the response might help you solve this mystery.

I used to turn my previous center speaker up about 6 or 7dB louder than my mains for intelligibility. It also sounded boxy at times -- not often, but enough that I eventually upgraded. My current center is now about the same volume as my mains, because it's a better center and easier to understand dialog at lower levels.

But upgrading the center channel was not simply a matter of swapping out drivers in an existing cabinet. To answer your question:



No. This is not a good idea at all. As I mentioned in post #12, there's a lot of knowledge, time, and effort that goes into designing a worthwhile center channel speaker; and replacing drivers based purely on their sensitivity is a recipe for disaster.

Hey rojo, come to think of it I have no port hole in my centre channel speaker at all and did not think about that until you mentioned it.I did not even notice until now,as all my surrounds are ported at the rear and my mains at the front.I really do have a lot to learn about speakers rojo.My speakers as you see on the front stage are now off the wall a good foot and a bit as that photo is an old shot but it's good you noticed.I did an spl test today and cranked them up to 75db as my mains are -3.5 and my centre is +2 and it sounds better now but I am willing to try what you suggest.One thing to note is that my room is quite large at 8.5m x 5.5m.