DIY Super Center Channel

tryrrthg

Early B. wrote: »

Damn. If it's gotta be WWMTMWW, then we're right back at the Dynamic 4CC... I sent the guy an e-mail last night. Awaiting a response...

I would not hesitate to get the Dynamic 4CC. I recognize that guys work from HT guide. He builds nice stuff. It will be a top notch DIY design. Get it and put some bass bins under it.

shadowofnight

Early B. wrote: »

I've tried a dual center channel setup before, and it worked very well.

I didnt see the size of your monitor mentioned yet ? When I went to a 58" plasma , the actual center point of the center channel sound was lower then the actors/dialog source on the large screen.

I went from 1 center channel to 4 center channels ( 2 above and 2 below the 58" screen ) and got a perfect point source for the center channel directly in the middle of the screen. Everybody who has heard it couldnt stand to keep just one center channel anymore, it really improves the center channel's steering during L/C/R transitions and dialog clarity.

I also experimented with a center channel sub ( Actually I have experimented with a sub per all channels before ) quite a bit.....you run into bass cancellation issues when feeding the center full range sound with a center channel sub hooked up....the best method I found was overbuilding the center channel with drivers designed for awesome midbass and midrange /highend clarity then worrying about anything below say 30 Hz or so response...let them excel at the frequencies you really need for a center channel and over build your LFE/sub channel for the dramatic lowend.

My LFE channel pounds the sidewalk across the street with the windows and doors closed, so I am a bass junkie as well....but it really works better to leave the really low bass frequencies to the one LFE channel and overbuild the center channel for what it was really designed for...the bass cancellation is real and measurable the other way around.

To build your monster center setup , I would go for multiple 6 1/2 " drivers above and below the screen if it is as large or larger then say a 50"....under 50" ...above or below works fine...but if the screen is larger the above and below is worth its weight in gold.

ben62670

6 6.5's is roughly a 22 inch sub, and we can hit 40hz 3db down;)

Early B.

shadowofnight wrote: »

I didnt see the size of your monitor mentioned yet ? When I went to a 58" plasma , the actual center point of the center channel sound was lower then the actors/dialog source on the large screen.

I went from 1 center channel to 4 center channels ( 2 above and 2 below the 58" screen ) and got a perfect point source for the center channel directly in the middle of the screen. Everybody who has heard it couldnt stand to keep just one center channel anymore, it really improves the center channel's steering during L/C/R transitions and dialog clarity.

I also experimented with a center channel sub ( Actually I have experimented with a sub per all channels before ) quite a bit.....you run into bass cancellation issues when feeding the center full range sound with a center channel sub hooked up....the best method I found was overbuilding the center channel with drivers designed for awesome midbass and midrange /highend clarity then worrying about anything below say 30 Hz or so response...let them excel at the frequencies you really need for a center channel and over build your LFE/sub channel for the dramatic lowend.

My LFE channel pounds the sidewalk across the street with the windows and doors closed, so I am a bass junkie as well....but it really works better to leave the really low bass frequencies to the one LFE channel and overbuild the center channel for what it was really designed for...the bass cancellation is real and measurable the other way around.

To build your monster center setup , I would go for multiple 6 1/2 " drivers above and below the screen if it is as large or larger then say a 50"....under 50" ...above or below works fine...but if the screen is larger the above and below is worth its weight in gold.

Thanks for the input. My TV is a 50 incher. Due to the setup, I'm confined to setting the center channel below the screen.

Early B.

tryrrthg wrote: »

I would not hesitate to get the Dynamic 4CC. I recognize that guys work from HT guide. He builds nice stuff. It will be a top notch DIY design. Get it and put some bass bins under it.

Yeah, I'm leaning in that direction. The only thing stopping me is a couple hundred bucks. I may just say, "'Eff it!" and buy it, then figure out the financials later. Awaiting an email response...

Still might build the bass bins, though, but not for the center channel. I can build two of them for about $30 each, so not much to lose if they don't work out. I have everything I need except the MDF and paint.

ben62670

OK so now you don't care about bass in the center Budget is way over as is. You do have a sub amp? I have those replacement Vifa ring radiators in now. They came today:) Can you stop in for a few?
Ben

Early B.

ben62670 wrote: »

OK so now you don't care about bass in the center Budget is way over as is. You do have a sub amp? I have those replacement Vifa ring radiators in now. They came today:) Can you stop in for a few?
Ben

Huh? If the 4CC goes into the 30's, then I'm fine.

No, no sub amp, but I have a two extra channels on my multi-channel amp and a stereo sub crossover.

Yep. The 4CC will push the budget way over the top, but it's almost exactly what I want. Funny how that always happens. Damn.

Face

You know if you don't do it right the first time, you'll never be satisfied. Then again, when are you satisfied?

tryrrthg

I built the Modula MTM's which use the Dayton RS180 drivers. They had pretty good bass response. Four of them in a single speaker should do the trick.

ben62670

Early B. wrote: »

Huh? If the 4CC goes into the 30's, then I'm fine.

No, no sub amp, but I have a two extra channels on my multi-channel amp and a stereo sub crossover.

Yep. The 4CC will push the budget way over the top, but it's almost exactly what I want. Funny how that always happens. Damn.

It does not go intoi the 30's. There is this thing called physics. Those drivers can not be tuned that low with less than .5 cubic feet each. It is not happening. End of story. If it goes into the 30's I will crap in my hat and eat it. His own website says the center rolls off at 80. Did you even look at the graph of the completed speaker?
http://clearwaveloudspeaker.googlepages.com/dynamic4tfrandimp
10db down at 50hz
6db down at 30hz
These were in room measurements.
Here are the specs for those woofers. Look at the vas
Specifications: *Power handling: 80 watts RMS/120 watts max *VCdia: 1.5" *Le: 1.0 mH *Znom: 8 ohms *Re: 6.4 ohms *Frequency range: 27-2,000 Hz *Fs: 27 Hz *SPL: 88.1 dB 2.83V/1m *Vas: 2.75 cu. ft. *Qms: 1.60 *Qes: .47 *Qts: .37 *Xmax: 7 mm
If anyone has BassBox could you please run these numbers. The box they want is 2feet.

here are even more specs
http://www.parts-express.com/pdf/RS225S-8_specsheet.pdf

Dude I'll build it just like they want. No problem, but like I have said I really doubt it will do what they say. It's a center. I don't want you to be dissapointed. We'll see when someone else crunhes the numbers. Maybe I am wrong, the guy at Madisound is wrong, and WINisd is wrong.

ben62670

OK I talked to PE. They ran it on BassBox. He laughed. I laughed. We can mod the box to around 5 feet. It will work. Order up sucka:D We are going super size on this one Hoss!
Ben

ShinAce

ben62670 wrote: »

These were in room measurements.

My bold.

Is anyone surprisd by this? I'm not. An F3 lower than an Fs, hmmmm....

ben62670

ShinAce wrote: »

My bold.

Is anyone surprisd by this? I'm not. An F3 lower than an Fs, hmmmm....

Nice big 10db dip at 50hz:rolleyes: We can do it nearly flat to 40 add room game, and his goal has been reached:)

ShinAce

ben62670 wrote: »

Nice big 10db dip at 50hz:rolleyes: We can do it nearly flat to 40 add room game, and his goal has been reached:)

That's gonna depend on the room. Right?

ben62670

ShinAce wrote: »

That's gonna depend on the room. Right?

I am sure it is, but when I modeled those speakers it is not pretty on paper. Try to model it bro. See what you come up with. Please don't feel I am knocking the design. Most centers are XOed at 80. It is wonderful to 80. Most people don't want a huge box for a center. I have been to Early's house, and he has an ideal spot for a large box. His mains are towers that are about four feet tall. A taller center will help. Maybe he can post a pic of the cubby it will sit in, and you will see where I am coming from. If you want try to model it, and check it out. An extended -3 shelf may be adventitious if you figure in room gain:)
Ben

megasat16

GV#27 wrote: »

Atleast some DVD's do contain low bass in the center channel.Widescreen Review does a spectral analysis of the DVD's they review and their results indicate that some soundtracks(mostly action flicks) contain some deep bass info in the CC.I use a full range center and have found that to be the case aswell.
But as you say the most important goal for the CC is the accurate reproduction of the dialog.

Yes! I agree that some soundtracks have Low Frequency Bass in the center. My worries is that if you must have a really all good around center that will dig low and producing the accurate mids and highs, it's nearly impossible to build cheaply using low cost drivers.


I think the accuracy of the good sound is more important for the center than the capability to produce 20-40Hz LFE in the center. Besides, if you have a really good sub in the room, it's most likely the sub will overwhelm the LFE coming from the center in some instances.

The sound theory suggests that if you have multiple driver producing a good sound as well as a bad sound, the sums of the bad sounds produced from multiple drivers also increases as the sums of the good sounds produced from multiple drivers. So, you are hearing multiples of the good sounds as well as multiples of the bad sound if the XO is not implemented properly. That is especially the case of two woofers and two mid-woofers design using passive XO where room gain and driver placement will interact with the Frequency Response of the center considerably. It's most likely the XO needs to be tweaked and modified several times which will cost more money. Multiple drivers playing the overlapping area of the XO is also not very desirable such as in WMTMW or WWMMTMMWW and spells like a disaster.

I think if one must really really have low frequency effects in the center, have a couple of subs crossed for below 150Hz and so build a kick-**** MTM with better drivers. If I have a choice for my own center, I would use one or two ribbon in conjunction with the ring radiator tweeter with two mid-bass (may be 7-8") for center.

But this is not very feasible with the proposed budget by the OP.

ShinAce

reserved for later

new post arrived while typing

tryrrthg

ben62670 wrote: »

It does not go intoi the 30's. There is this thing called physics. Those drivers can not be tuned that low with less than .5 cubic feet each. It is not happening. End of story. If it goes into the 30's I will crap in my hat and eat it. His own website says the center rolls off at 80. Did you even look at the graph of the completed speaker?
http://clearwaveloudspeaker.googlepages.com/dynamic4tfrandimp
10db down at 50hz
6db down at 30hz
These were in room measurements.
Here are the specs for those woofers. Look at the vas
Specifications: *Power handling: 80 watts RMS/120 watts max *VCdia: 1.5" *Le: 1.0 mH *Znom: 8 ohms *Re: 6.4 ohms *Frequency range: 27-2,000 Hz *Fs: 27 Hz *SPL: 88.1 dB 2.83V/1m *Vas: 2.75 cu. ft. *Qms: 1.60 *Qes: .47 *Qts: .37 *Xmax: 7 mm
If anyone has BassBox could you please run these numbers. The box they want is 2feet.

here are even more specs
http://www.parts-express.com/pdf/RS225S-8_specsheet.pdf

Dude I'll build it just like they want. No problem, but like I have said I really doubt it will do what they say. It's a center. I don't want you to be dissapointed. We'll see when someone else crunhes the numbers. Maybe I am wrong, the guy at Madisound is wrong, and WINisd is wrong.

The RS180 designs I've seen ALL extend into the 30's. My Modula MTM's were tuned to 28 hz and had ample bass response. Even the Modula MT is tuned to 32hz without any problems. In his graph he states that he did not include port output which would extend the response. If he says they play into the 30's he isn't lying.

EDIT: You are looking at the wrong driver. He doesn't use the RS225 in that center channel. he is using four RS180's

megasat16

Both RS180 and RS225 graphs are shown with smooth roll off below 200Hz but may not be actual as it's suggested in the data sheet. :eek:

ben62670

tryrrthg wrote: »

EDIT: You are looking at the wrong driver. He doesn't use the RS225 in that center channel. he is using four RS180's

:o:o:o:o
Ooops
Thats helps a bit:o, but it still wants a bigger box.
Thanks T for the correction! I'll get on the box later:(

megasat16 wrote: »

Both RS180 and RS225 graphs are shown with smooth roll off below 200Hz but may not be actual as it's suggested in the data sheet. :eek:

I just plugged it in. Boxed, and tuned it is looking pretty good;)

Systems

ben62670 wrote: »

His own website says the center rolls off at 80. Did you even look at the graph of the completed speaker?

OK one more time;) the speaker represented(4T or 4cc?) in that in room response measurement is rolling off below 75hz .But the designer points out that he did not splice the ports response in with the measurentments.Therefore the ports contribution is not shown.If he had spliced it in the output below 75hz would have been subtantially higher.Also the impedance plot cleary shows that the port is tuned to 30hz.If a box is tuned at 30hz it will certainly have output below 80hz.Maybe both measuerments were of the larger boxed 4T.(I don't see anywhere mention of 80hz on his site).

Systems

ben62670 wrote: »

:o:o:o:o
Ooops

You silly.:D

Systems

Early B. wrote: »

The only thing stopping me is a couple hundred bucks.

Just hock some of the wifes jewelry,if she finds out just tell her it was for a good cause.

Early B.

Face wrote: »

Save yourself the headache, get a better pair of mains and go phantom.

Just finished demoing my system with a phantom center channel. IT SUCKS!!

Actually, voices sounded better than I anticipated, and it's suitable for temporary listening, but there's an awful lot of effects missing. First, the bass and dynamics suffer dramatically. Second, it simply doesn't have the full surround sound presence.

I also came to another realization -- Trey's absolutely right about center channels being terribly overpriced for what they do.

megasat16

Are you hell of confused to make any plans for the center?

Early B.

megasat16 wrote: »

Are you hell of confused to make any plans for the center?

I'm ready to purchase the Dynamic 4CC kit. I've sent two e-mails so far, but haven't gotten an answer yet. I may need a backup plan.

Face

Early B. wrote: »

I'm ready to purchase the Dynamic 4CC kit. I've sent two e-mails so far, but haven't gotten an answer yet. I may need a backup plan.

How about one of these?

Early B.

Face wrote: »

How about one of these?

Nah. Not big enough for me. It only has two woofers.;)

monstershed

Hi all I have ATS Acoustic panels for sale, they are 2x4x2 and I will take 150.00 for the box of 6. These cost 45.00 a piece email me at rippy43@yahoo.com

edbert

Thanks for stopping by monstershed. Next time follow the rules.