DIY Super Center Channel

Early B.

ben62670 wrote: »

2 8's $110
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-376
2 5.5's $25
http://www.madisound.com/catalog/product_info.php?manufacturers_id=150&products_id=844
1 nippled tweeter $50
http://www.madisound.com/catalog/product_info.php?manufacturers_id=153&products_id=1181
I was thinking the double magnet Vifa, but the cheaper one should be a better match. It is 91.5 VS 92.7db. I would like to keep a resistor out of the tweetercuircuuit if possible. Also I prefer the Silver Flute 8's to the Dayton's. They are also cheaper, and go low.
The drivers would be less than $200:)

What about the crossover design?

C'mon Ben, admit it -- you wanna design this speaker, don't you?

That's partly why I'm asking about the cost of the box. The Dynamic 4CC may be beyond my budget. I'm still deliberating 'cause it looks badass.

ben62670

GV#27 wrote: »

How does it not reach his design goals?

But with the kit you have an expertly designed crossover that according to the measurements does an excellent job of blending the drivers.The xover is the most important part.

He wants it to go deep. The design only goes to 80hz. The website states this, and so does modeling the drivers. As for the XO he is going to have Madisound do it for him. I certainly don't want to do a 3way. For myself I would, but it needs to be done right the first time;)

Box price will be about $200 after you figure all the hardware, MDF, veneer, and finish.

Early B.

ben62670 wrote: »

Who is going to finish the cab? I can veneer it for you, but you will stain, and clear coat it?

I dunno. I don't plan to put a lot of time and money into finishing the cabinet. Only the front will be visible. I may decide to paint it black and be done with it. I think veneer will be very nice, but probably cost more than I want to spend.

ben62670

Painting is not that easy. You still need to seal it($), sand it(lots of time), and paint it(more money). We'll talk. We have options:)

Early B.

ben62670 wrote: »

Box price will be about $200 after you figure all the hardware, MDF, veneer, and finish.

Hmmm. Full kit price is $570 plus $200 for the cabinet is $770. That's a good distance past my budget. I'm going to bed. I'll decide tomorrow.

Systems

ben62670 wrote: »

The design only goes to 80hz. The website states this, and so does modeling the drivers.

Actually the site says it will dig into the 30's and as I mentioned in a previous post he did not splice in the ports response thus explaining the drop in level below 75hz in his measurement.Also take a look at the impedance curve,it clearly shows the port is tuned to about 30hz.So that tells us that bass extension will be well below 80 hz.However if you used a sealed box instead of ported ,then you may only be in the 80 hz range.

Early B.

ben62670 wrote: »

Painting is not that easy. You still need to seal it($), sand it(lots of time), and paint it(more money).

You've never seen my handiwork, have you? Two coats and I'm done. Sanding -- hell, no!:p

ben62670

GV#27 wrote: »

Actually the site says it will dig into the 30's and as I mentioned in a previous post he did not splice in the ports response thus explaining the drop in level below 75hz.Also take a look at the impedance curve,it clearly shows the port is tuned to about 30hz.So that tells us that bass extension will be well below 80 hz.However if you used a sealed box instead of ported ,then you may only be in the 80 hz range.

Try to model it. I WINisded the thing, and it won't go low in a 4.5 foot box(1.1 per driver). It likes 8.5;) I could have made a mistake, but I doubled checked it.

megasat16

The 4CC really got you digs? I think it looks cool with most resemblance to the Paradigm Signature Center.

I think I should really remind you one thing what others have been saying. There is not much low frequency content in the center channel (even with full range setting on the AVR) because there is not much low frequency encoded into the center for most DVD / BluRay Movies. It may be different with 2 Channel listening but who listens to center for 2 channel listening. For SACD and DVD Audio, most tracks will not have a lot of low frequency for center to work. So, mostly the huge center will serve it's purpose as a pedestal for the TV above it and most likely the bass drivers installed in it will be used for mid bass most of the time. So, having mid bass and low bass in this might not be really necessary and get the higher quality mid-bass drivers may be more appropriate. This will also reduce the complexity of the XO design as it's can be 2 way (2.5 if you want to add ribbon) and not a full 3 way.

I think I understand you are trying to make your center ready for any task that comes across. But the main duty for center is the really life like dialogue to keep you staring at the screen above (or below) the center speaker. So, it would be most likely designed to have accurate mid bass and crystal clear highs with natural warming sound and the mids and highs are more important than the lows. The 4CC may achieve that and then some. But the full kit costs of $570 may includes the cabinet (but not finishing)?

bsoko2

Stack two CS350's and be done with it!

Bill

megasat16

bsoko2 wrote: »

Stack two CS350's and be done with it!

Bill

Or stack two LSiCs and I could swear that suddenly the center disappears (not only in sweet spot but all different seating across the entire room) and real people talking in front of me. :cool:

In fact, I have 3 LSiCs and could probably improve more by adding 1 more but I don't have space for it. It might have to go rear of the room when I try it next time.

Systems

ben62670 wrote: »

Try to model it. I WINisded the thing,

I have Winisd so I may give it a try tonight.

Systems

megasat16 wrote: »

I think I should really remind you one thing what others have been saying. There is not much low frequency content in the center channel (even with full range setting on the AVR) because there is not much low frequency encoded into the center for most DVD / BluRay Movies.

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.

tryrrthg

Early B. wrote: »

The Statement is cool, but not big enough. What I want is essentially a large floorstanding speaker for a center channel. Hell, I even thought about using one of my VMPS speakers as a center channel (16x16x44).:p

Then what is wrong with the WMTW center channel with two 8 inch drivers?

http://www.htguide.com/forum/showthread.php4?t=15323

http://www.htguide.com/forum/showthread.php4?t=22393

Early B.

megasat16 wrote: »

I think I understand you are trying to make your center ready for any task that comes across. But the main duty for center is the really life like dialogue to keep you staring at the screen above (or below) the center speaker. So, it would be most likely designed to have accurate mid bass and crystal clear highs with natural warming sound and the mids and highs are more important than the lows. The 4CC may achieve that and then some. But the full kit costs of $570 may includes the cabinet (but not finishing)?

OK, I woke up this morning with a different approach consistent with what megastat is saying here.

First, I'd love to do the Dynamic 4CC project, but I gotta be mindful of the budget.

Second, the center channel has to eclipse every other center channel I've owned before; otherwise, I could have kept the one I had. I want it to be unique and to serve all of the goals of the project.

Third, sound quality is the most important factor.

Fourth, The ability of the center channel to go low is significant, but not simply for the sake of capturing low bass content. What I really want are larger drivers than the typical 5.5 or 6.5 because I want more presence and dynamics. It's like the difference in sound between a typical bookshelf speaker an authoritative floorstander with large drivers.

Fifth, I think we ought to redirect our approach to finding the best drivers in my price range. If I want huge sound, let's dispense with trying to get an array of 7" or 8" drivers to make that happen, and use larger woofers for the lows. That way, we can focus on sound quality using two midrange drivers and a tweeter. As I mentioned earlier, I already have a pair of 12" carbon fiber drivers. How about crossing them over fairly low (i.e., 150 Hz - 200 Hz) and concentrate on getting the midrange right.

Sixth, of course my biggest concern is the design of a crossover. The 4CC is very appealing for this reason, but if I can feel comfortable that we can design a decent 3-way crossover, then I'd rather build my dream center channel -- 14x14x48 with dual 12" woofers.

In fact, we can even make the job easier with a 2-way design and using the 12" woofers as "subwoofers." I already have the external crossover and amplification for them. Use of the 12" drivers allows me to focus my budget on a pair of top quality drivers and a tweeter(s).

So let's say my budget is $500. Here's how I see it: $250 for the cabinet and $250 for a pair of midrange drivers and a tweeter(s).

Now, let's go back to discussing the crossover design. Based on this new approach, we can probably find several DIY MTM designs that would work well for this purpose. In fact, we can build a single MTM and attach the subs to it (or not). (We may have to tweak the crossover design to accomodate the subs, though.) In other words, the center channel would still be 48" long or thereabout, but the middle section would not be as deep as the two end sections that house the 12" woofers. Hell, I may even be able to minimize the cabinet building process by purchasing a finished MTM cabinet and building two separate subwoofer boxes, and make them appear as one unit.

What do you guys think?

Face

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

ben62670

We don't have any specs for those woofers...

ben62670

http://clearwaveloudspeaker.googlepages.com/dynamic4cc
2.1 cubic feet not including drivers, or bracing:(
If the box changes dramtically then the XO would have to change?

Early B.

Face wrote: »

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

Without a center channel, I'm doing that right now.

Early B.

ben62670 wrote: »

We don't have any specs for those woofers...

Is that a deal breaker for using them as "subs?"

Early B.

Here's what I want:

1. 12" dual "subs" with external crossover
2. 8" pair of midrange drivers
3. Vifa ring radiator tweeter
4. minimize building the cabinet (building a large cabinet takes too much time and money; plus it will be heavy as hell) by buying the MTM cabinet and building separate 14x14x14 boxes for the subs
5. tweak an existing proven crossover design
6. to be completed within 3 weeks
7. visual appeal (imagine staring down at dual 12" subs and a pair of 8" drivers while watching a movie!); also, it's gotta pass the WAF test
8. stay within budget ($500)

Can I get everything I want???

SolidSqual

Early B. wrote: »

Here's what I want:

1. 12" dual "subs" with external crossover
2. 8" pair of midrange drivers
3. Vifa ring radiator tweeter
4. minimize building the cabinet (building a large cabinet takes too much time and money; plus it will be heavy as hell) by buying the MTM cabinet and building separate 14x14x14 boxes for the subs
5. tweak an existing proven crossover design
6. to be completed within 3 weeks
7. visual appeal (imagine staring down at dual 12" subs and a pair of 8" drivers while watching a movie!); also, it's gotta pass the WAF test
8. stay within budget ($500)

Can I get everything I want???

For today, you are my hero.

http://www.youtube.com/watch?v=LFjKFDvyJ80

Early B.

GV was on the right track with this post. I wanna do a variation of this with my 12" woofers:

GV#27 wrote: »

Get a decent 2 channel amp and active crossover like the Marchand XM1 kit then actively crossover at 200- 300hz to a pair of 8"' or 10"s.
example, http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-456 these 8"s have long excursion capabilty and low Fs so a pair will have serious output capability and they will dig into the low 30's in a reasonable size box.

Then you will have a passive/active center with excellent dialog reproduction from any seating position due to the coax's excellent dispersion and lack of lobing issues,and lots of spl potental below 300hz with the dual woofers.

BTW -- the woofers I'm referring to were taken out of my VMPS floorstanders and replaced. They performed midbass duties. I think, though, it is the same driver for the low bass, as well.

ShinAce

GV is spot on in all posts within the thread.

He's giving you detailed, honest, and helpful ideas.

tryrrthg

Early B. wrote: »

Here's what I want:

1. 12" dual "subs" with external crossover
2. 8" pair of midrange drivers
3. Vifa ring radiator tweeter
4. minimize building the cabinet (building a large cabinet takes too much time and money; plus it will be heavy as hell) by buying the MTM cabinet and building separate 14x14x14 boxes for the subs
5. tweak an existing proven crossover design
6. to be completed within 3 weeks
7. visual appeal (imagine staring down at dual 12" subs and a pair of 8" drivers while watching a movie!); also, it's gotta pass the WAF test
8. stay within budget ($500)

Can I get everything I want???

No. You can't just throw random drivers in a box and use a "proven" crossover. To do it correctly you need to mount the drivers you want to use on the baffle size you want. Then take measurments and design the XO around the drivers/measurements. That is why I suggested the two center channels from HT guide. Those guys have done that for you (and a LOT of work at that) and MANY people have built the designs with great results. If you want subs then just build some bass bins to sit under the proven center channel design and use some sort of external xover to blend them with the center channel.

ShinAce

I'd like to take a moment to mention that the distance between the mid and tweeter(or whatever combo you want) is important in the crossover design. Once you take into account dispersion(lobing), crossover frequency, and separation, you might have to go with a different type(topology) of crossover.

This is especially important with Appolito designs. I think the seperation from center of tweeter to center of mid should match the wavelength of the crossover frequency when combined with a second order slope. Better look that one up though, I'm quoting from memory.

Early B.

tryrrthg wrote: »

No. You can't just throw random drivers in a box and use a "proven" crossover. To do it correctly you need to mount the drivers you want to use on the baffle size you want. Then take measurments and design the XO around the drivers/measurements. That is why I suggested the two center channels from HT guide. Those guys have done that for you (and a LOT of work at that) and MANY people have built the designs with great results. If you want subs then just build some bass bins to sit under the proven center channel design and use some sort of external xover to blend them with the center channel.

The "bass bins" is exactly what I'm suggesting.

I'm not gonna "just throw random drivers in a box." That's why I talked earlier about building a MTM based on a proven model. I'm not in the business of designing crossovers. I'm gonna take your advice and use someone else's design. The design I'm looking at uses a Vifa tweeter and 8" drivers, so that's why I mentioned it. I may not need to do #5 though, but if not, that means the lowest frequencies will overlap.

tryrrthg

Early B. wrote: »

The "bass bins" is exactly what I'm suggesting.

I'm not gonna "just throw random drivers in a box." That's why I talked earlier about building a MTM based on a proven model. I'm not in the business of designing crossovers. I'm gonna take your advice and use someone else's design. The design I'm looking at uses a Vifa tweeter and 8" drivers, so that's why I mentioned it. I may not need to do #5 though, but if not, that means the lowest frequencies will overlap.

I must have missed the MTM with vifa tweeter. where is that design from?

ben62670

tryrrthg wrote: »

I must have missed the MTM with vifa tweeter. where is that design from?

4 8's, and a vifa;) but it is not happening.

I talked to Madisound, and it looks like WWMTMWW. I knew from building my SDA's that drivers need to be close enough to each other to prevent lobing. 6.5's need to be crossed no higher than 2350. The 8's would have to be at around 1800. This would put way too much stress on the tweeter. I am still working on the design. I am not just pulling a rabbit out of my butt;) I have a pair of 5.5's here, and the Vifa ring radiator so We can do some simple test before we start making purchases.
Anyone have Bass-box?
Thanks
Ben

Early B.

ben62670 wrote: »

4 8's, and a vifa;) but it is not happening.

I talked to Madisound, and it looks like WWMTMWW. I knew from building my SDA's that drivers need to be close enough to each other to prevent lobing. 6.5's need to be crossed no higher than 2350. The 8's would have to be at around 1800. This would put way too much stress on the tweeter. I am still working on the design. I am not just pulling a rabbit out of my butt;) I have a pair of 5.5's here, and the Vifa ring radiator so We can do some simple test before we start making purchases.
Anyone have Bass-box?
Thanks
Ben

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...