Censcala project underway...

[chops]

So what is a Censcala?

Well, in my mind, it is a Cornscala, but designed and built specifically for 5.1 music and movie center channel duty. The only problem I have is coming up with a good design.

Before I decided to go the Cornscala route, I originally thought about building an identical Cornwall cabinet (exact dimentions), but on its side with a CT1526 (Bob's version of the K-33), aluminum K-600 and CT125 (Bob's version of the K77) above one another and with an angled riser, and the port would be split into two, one on either side of the woofer. The drivers would be close together much like in the Heresy, but in the middle of a much wider cabinet.

My second idea was using two CT1526 woofers on either side of the squawker and tweeter horns. This would probably sound really good, but then the network would have to be modified to cope with the 4 ohm load of the two woofers wired in parallel, not to mention that the enclosure would have to be 12+ cu.ft. IOW, it would be huge! The good thing about this design is that it would keep the mid and tweet right in the center.

Now since I am using these Pyle Pro squawker horns, I have to rethink everything again.

I have an exterior cabinet limit of 26" high (right up to the bottom of my projection screen) which prohibits mounting the drivers above one another since the CT1526 is obviously a 15" woofer which is almost 15" tall, the Pyle Pro squawker horn which is almost 11" tall, and the CT125 which including the magnet is almost 3.5" tall. Add all of that up and we're now up to nearly 30" tall, and that's not including the 2" minimum gap between driver and cabinet on the motorboard itself. With that and the .75" birch plywood on top of that, we have a grand total of 35.5", which puts the cabinet 9.5" into the screen. OH, and I almost forgot about the 2" angled riser. That makes it 37.5" tall, or 11.5" into the screen!

So I am now thinking of doing my "Censcala" version of the Vertical Cornwall, but with a twist. I am still going to use a 2" riser to match the CWs, but it will also be flat like the CWs. The cabinet on the other hand will have a slanted motorboard so that the drivers are aiming slightly upward. I'll have the woofer on one side and the squawker and tweeeter on the other side. They will all be mounted high up in the motorboard with the port running below them like in the CWs.

I do have a couple of questions also...

1) Being that the woofer is off to one side and the squawker and tweeter are off to the other side of the motorboard, how does the Vert CW sound? Does it keep the dialog centered or is it shifted off more towards the higer freq drivers?

2) I can figure out dimentions and cu.ft. of enclosures when they are built with 90* angles, but how do I figure out the cu.ft. of an angled enclosure? Remember, the enclosure (minus the riser) can only be a MAX of 24" tall and must be the recommended 6 cu.ft. for the driver.

I have everything ordered and on its way here from Bob, including a custom Type CS II network. However, the CT1526 woofers are backordered, so I'll just have to substitute an old Pyle Pro PPA15 woofer from my old dipole subwoofer project until the CT1526's come in. Speaking of Pyle Pro, I also have another one of their squawker horns on the way. I'm going to the extremes of even using the old fashon terminal strip on the back panel of the cabinet just like the ones on the back of my CW cabinets, just to keep this center channel as close as possible to the mighty CWs.

Here's a cheezie drawing I did of the three different designs I spoke about. It's 1024x768, so it might be best to click on it and view it on a new page. And yes I know... Apparently I can't draw the drivers and ports perfectly centered on the motorboards. LOL Oh well, you get the point.

I'm open for suggestions, so please feel free to mention anything you might think of or have questions about.

Charles T

[BS Button]

Wonder how that horn would sound mounted vertically?

[BEC]

I am thinking #3.

Bob Crites

[chops]

Wonder how that horn would sound mounted vertically?

I actually tried that. I took the top hats and flipped them vert first with the tweeters on the inside, then on the outside. Honestly, I didn't care for it. They sounded disconnected from the music or something. They were lacking something. [:^)]

[Deang]

"Here's a cheezie drawing I did of the three different designs I spoke about.."

I don't see the cheezie drawings, just the three good ones.!

[chops]

Bob,

I'm inclined to agree with you. Obvioulsy at this point #'s 1 and 2 are out of the question. The real question at this point though is if I should use the slanted motorboard or just do a normal "square" cabinet and use an angled riser? The latter would definately be the easier way to go.

One of my customers at work which has actually turned out to be a pretty good friend is a skilled woodworker which has already offered to help me out with this project. So with that being the case, I might just test his skills and see what he has to say about building the slanted cabinet. He's an old southern boy and doesn't know squat about speakers. []

Dean,

Thanks for the complement! As you can tell, these were just quickie free-hand sketches that I whipped up, and I just took a picture of it instead of using the flatbed.

Lazy?... maybe. Quick and simple and gets the point across?... hell yeah! LOL []

[BEC]

I really like the slanted motor board and level top. Will be a bit more difficult in planning and construction, but with careful planning for the angle, should be a real winner.

Bob

[chops]

I really like the slanted motor board and level top. Will be a bit more difficult in planning and construction, but with careful planning for the angle, should be a real winner.

Bob

Me too. I think it really sets it off and makes it unique. And I'm almost 100% sure my friend can pull this off in his shop as well. You should see the ink pens he makes out of all these different exotic woods from around the world.

Anyway...

[colterphoto1]

I really like the slanted motor board and level top. Will be a bit more difficult in planning and construction, but with careful planning for the angle, should be a real winner.

Bob

Yes, I agree, #3 is the one to build, the slant will help keep early reflections off of the floor. You won't notice the slightly offcenter configuration at all. Nice work. Is the cabinet volume the same as normal CW or are you having to reconfigure the port? Dr. Who might have some input on driver placement, but looks good to me.

I think you're correct about not reorienting the mid horn, but the tweeter could probably go either way. Keep it simple though.

[J.4knee]

"I can figure out dimentions and cu.ft. of enclosures when they are built with 90* angles, but how do I figure out the cu.ft. of an angled enclosure? Remember, the enclosure (minus the riser) can only be a MAX of 24" tall and must be the recommended 6 cu.ft. for the driver"

Easy way to do this, as long you know how much your angle is going to be, the size of your face (motorboard) your good to go. Use the formula for the area of a trapezoid. A = (h/2)(a+ Where "a" is the top of your speaker in the drawing, "h" is the backside or height and b is the long under side. Multiply that number by the length of your cabinet to get volume. Or you can use two separate formulas the area of a triangle ½ base x height, multiplied by the length of the speaker will give you the volume of your triangle and then you have a simple rectangular box to derive your other dimensions from and you already know your desired volume overall so just subtract the triangular volume from the overall volume and construct a rectangular box based on that remaining volume. If you are having trouble figuring out your triangular dimensions remember your motoboard is your hypotenuse of the triangle and just take the sine of your angle to determine the base which is the hypotenuse/opposite side and your height is derived from the cosine of your angle being the adjacent side / hypotenuse. Hope this helps<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

[jorjen]

Number 3 is the only choice Man!

Is it done yet? []

[customsteve01]

#3 is the one to use.

I really want to know what you think when you get tis built

Steve

[BEC]

Just make the internal raw volume approximately 6.4726649 cu. ft. and the port area 50 square inches.

Bob

[chops]

"Yes, I agree, #3 is the one to build, the slant will help keep early

reflections off of the floor. You won't notice the slightly offcenter

configuration at all. Nice work. Is the cabinet volume the same as

normal CW or are you having to reconfigure the port? Dr. Who might

have some input on driver placement, but looks good to me.

I think you're correct about not reorienting the mid horn, but the tweeter could probably go either way. Keep it simple though."

Hi Mike,

Yes, I'll be keeping the same volume and port tune as the CW. In fact, the port dimentions will be exactly the same as that of the CW, just positioned in the bottom center of the motorboard.

I just realized something else about this slanted design also. Being that it is slanted, that means the motorboard will be slightly larger than the CW's, so that will buy me a little extra room for driver placement as well.

J.4knee,

I'm sorry, but I don't speak Greek. [:$]

Serioulsy though, I think that if I read your post a couple times tomorrow when I'm more awake, I'll be able to figure out how to calculate the cu.ft. properly. Thanks!

Charles

[chops]

Jordan... I wish! LOL

Steve... Me too.

Bob... Will do. []

[jwc]

chops,

Yes you would need the area of a trapeziod x length to get the volume. I had to do this many different ways to get my dbb's right. If you want to tackle the idea, send me some internal measurements and I can get back to you on the fly with results.

I, However, think that the phrase "keep it simple" won't apply to that design. That is complicated and I am sure you will be proud of your results because it would be unique (sp).

The slanted idea seems neat but I would personally choose #1. You could adjust the riser to your liking and you would have all the drivers in the same vertical axis. The slanted one would look weird in my opinion if you had to adjust the angle to the listening position.

Is this going to be on the floor? If on furniture....how far in the air will it be? Will the listening position be in Lazy-boy like chairs.

Just my opinion. Here is what I did. My HT is in MC Bass mode and I don't care about the low end of the center channel getting below 60Hz. Therefore no Porting. I also didn't want some bass machine speaker around my TV. In the picture, I ended up putting the speaker underneath the TV to one side and angled it to the listening position. This Herescala is level with my head as well as my Cornscalas when in my Lazy boys. Slant design wouldn't have worked here. It would...maybe if I left it on the floor. then i would trip on the damn thing.

jc

[jwc]

oops. Actually what I meant to say is the the Herescala is set to "small" so that the low frequencies are sent to the Sub.

[chops]

chops,

Yes you would need the area of a trapeziod x length to get the volume. I had to do this many different ways to get my dbb's right. If you want to tackle the idea, send me some internal measurements and I can get back to you on the fly with results.

I, However, think that the phrase "keep it simple" won't apply to that design. That is complicated and I am sure you will be proud of your results because it would be unique (sp).

The slanted idea seems neat but I would personally choose #1. You could adjust the riser to your liking and you would have all the drivers in the same vertical axis. The slanted one would look weird in my opinion if you had to adjust the angle to the listening position.

Is this going to be on the floor? If on furniture....how far in the air will it be? Will the listening position be in Lazy-boy like chairs.

Just my opinion. Here is what I did. My HT is in MC Bass mode and I don't care about the low end of the center channel getting below 60Hz. Therefore no Porting. I also didn't want some bass machine speaker around my TV. In the picture, I ended up putting the speaker underneath the TV to one side and angled it to the listening position. This Herescala is level with my head as well as my Cornscalas when in my Lazy boys. Slant design wouldn't have worked here. It would...maybe if I left it on the floor. then i would trip on the damn thing.

jc

Once I figure out some measurements, I'll see where I stand.

I sit on a futon which places my ears exactly at the same level as the throats of the K-600s in the CW cabinets with risers. This stupid futon sits you pretty low. Plus the dumb thing is about as comfortable as sitting on the top bar of a bicycle. Talk about a numb bum. LOL

Yes, the Censcala will be on a 2" high riser sitting on the floor. With the use of the Pyle squawker horn, there's simply no room whatsoever to fit all the drivers on a vertical axis in the limited amount of room I have underneath my projector screen.

[meagain]

Chops - I was again pondering my center channel dillemma today, thinking about your Cornscala project and again envisioning an Academy like version. Now - boom! You're doing it. Bravo

JWCullison - Well heck... I like yours also!

(still holding onto my fantasy BEC (or someone) will create a kit form of a nice heritage center for those of us who struggle with the concept of a big speaker where the TV needs to go. hint hint)

[formica]

I'm also going with the slanted motorboard and flat top so you know

what my choice is? My mains use the K400 and have about 30" to

play with, so the layout will be a mix of your #1 and #3... but very similar overall.

BTW, if you know your seating distance and height from the centre, you can

actually calculate the ideal angle for the motorboard. Nice sketches.

Easy way to do this, as long you know how much

your angle is going to be, the size of your face (motorboard) your good

to go. Use the formula for the area of a trapezoid. A =

(h/2)(a+ ...

It seems correct, but that does make for a difficult read...

In layman's terms... it's the same as finding a regular volume

(internal height x width x depth) where the depth is the average

depth. (for example the top is 16" and the bottom is 18"

deep... you can use 17")

The area of the trapezoid posted above is exactly that... average of dimension "a" and "b" times the height.

Keep us updated...

ROb