What determines baffle size and shape?

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I was asking about the shape and size of the front panel ... the baffle.

Okay ... So you are going to be dealing with baffle step comp, one way or another, regardless of width. So width can be based on your aesthetics design goals, within reason, and compensated for?
If this is so, then a wide front baffle with large radiused edges should be able to image and soundstage as good as really narrow front baffles?

Then if I have finally grasped correctly, what I wrote above, then I am next interested in thoughts on different designs of baffles; rounded, round edges, pyramid shaped liked like Avalon, etc.

Thanks for all the help.
 
Width of the baffle is determined by the driver diameter. The flat portion really doesn't need to be much wider than that. Around the tweeter and even the midrange, the nearer a baffle and its adjoining panels approximate a curved surface, the better. That means large radius edges. 3/4" routed edges are almost worthless, other than improving cosmetics and making the builder feel good. A truncated radius, such as hacking off the end of an egg and mounting a driver in it, is almost as bad as a square corner. The flat portion of the baffle must be tangential to the radius. An ellipse is actually better than a true radius. For woofers, angled edges are sufficient.

Position of drivers on the baffle is equally important. There should be no constant dimensions, so a baffle that follows the contour of a driver, such as rounded at the top with a driver at the center, is bad. Unequal distances from any edge, especially of the tweeter, is best. It's better to have the tweeter farther from the top than from the sides. A high forehead, if you will. The fewer parallel sides of the enclosure, the better, so that might influence the shape of the baffle. Thick is best, so that might be a factor in the shape, although the backside of openings must be relieved more around any driver that radiates from the rear. No tunnels. It also doesn't hurt if the backside of the baffle is broken up a bit from a flat, reflective surface.

Most of what you see in commercial designs is compromise for ease of manufacturing and maximizing profitability. If you have complete freedom to design anything, then, of course, you ultimately determine the shape. Ugly usually works better than beautifully symmetrical.

Peace,
Tom E
 
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baffle step comp, one way or another, regardless of width. So width can be based on your aesthetics design goals, within reason, and compensated for?

Not necessarily, but that seems to be the simple answer...
If this is so, then a wide front baffle with large radiused edges should be able to image and soundstage as good as really narrow front baffles?
Is flat what you require to begin with? Will the wide spray suit your conditions or will it present room reflections to affect imaging?
Then if I have finally grasped correctly, what I wrote above, then I am next interested in thoughts on different designs of baffles; rounded, round edges, pyramid shaped liked like Avalon, etc.
Some use odd shapes to 'compensate' for the issues that the edges can create. This means that the issue remains.
 
Wow ... This is great. I am starting a 3 way build soon. And this information helps me to understand much more.

I see a LOT of this being done, and kind of wonder why? ( please imagine this is a 2 piece, and not connected)

39453301795_25b4b0c313_z.jpg
[/url]main2-400x563 by Cullen Graham, on Flickr[/IMG]

Big bass cabs, with skinny upper cabinets. why?

Then I see a lot of Wisonesqe things, like this ...

38540660210_964baf14f4_z.jpg
[/url]af5dd9e1de137f2f036dfd3e03e33f4f--audiophile-speakers-audio-speakers by Cullen Graham, on Flickr[/IMG]

Is this for better imaging ?

If not for better imaging, then why wouldn't a person just do something like this, when they need a large bass volume? COULD it image as well, all things considered?

38540660470_58604621e4_z.jpg
[/url]1B1371_pair by Cullen Graham, on Flickr[/IMG]

And lastly ... if you need a large woofer on bottom, this seems the ultimate solution.

40305190432_c194f545ae_c.jpg
[/url]Vader_System_91b by Cullen Graham, on Flickr[/IMG]

I'm building a 12", 6.5", 5" tweeter soon. And I need to learn pros and cons, like I am in this thread. I have to come up with a design.
 
Wow ... This is great. I am starting a 3 way build soon. And this information helps me to understand much more.

I see a LOT of this being done, and kind of wonder why? ( please imagine this is a 2 piece, and not connected)



Big bass cabs, with skinny upper cabinets. why?

Then I see a lot of Wisonesqe things, like this ...



Is this for better imaging ?

If not for better imaging, then why wouldn't a person just do something like this, when they need a large bass volume? COULD it image as well, all things considered?



And lastly ... if you need a large woofer on bottom, this seems the ultimate solution.



I'm building a 12", 6.5", 5" tweeter soon. And I need to learn pros and cons, like I am in this thread. I have to come up with a design.

There is one commonality in all of the speakers posted is that none of them is really pleasing to a pair of eyes.
 
Cabinet Design = When in doubt, copy off of the smart kids.

For a front facing 12" woofer.
1) Klone the Avalon Eidolen cabinet. Truncated Pyramid bevels reduce diffraction effect, and also provide some diffraction dither which reviewers claim helps create a more realistic reproduction in a home. Neither the cabinet nor baffle need to be angled, and the bottom baffle bevels are not necessary.

2) LARGE full length side bevels can both reduce diffraction and set a STYLE.

3) Best simulation results from >3" radius edge rounds on L+R+Top baffle. Offset tweeter 0.8" - 1" from center. Locate tweeter about 6"-10" below the top round (10" = 1350Hz wavelength to avoid tweeter edge effects).

4) Smart kids get excellent simulation data. The $120,000 Magico all Aluminum cabinet with LARGE edge rounds is another Klone dream shape.

For a side facing 12" woofer.
1) Klone the edge-rounds on the Audio Physic KRONOS style cabinet, or use DEEPER edge-bevels on a Lansche 4.2 style cabinet.
 

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@ Andy2 ... You say none of those I posted are easy on the eyes. I tend to agree. I have never built a three way before. I have always made narrow two way towers, and stereo subs.

Now I have a 12" forward firing woofer to contend with. And it is going in 2.8 cu feet. And I am just struggling to figure a way to make a 14" wide cabinet attractive. Do I make two? Just one huge box? I realize I have options, but am struggling to figure out something pleasing to the eye, while keeping sound principals foremost. I just know I can't imagine using a large square tower, ah la 80s Klipsh style.

I think side firing is out, since I want to xover around 300hz to the mids.
 
Ah hah !!! My original post's question is answered in posts #28 and 29.

When I asked how a person determines baffle shape, size, etc ... what I didn't know is there IS a modeling program for what different baffle designs will do.

Told you I'm new to this, lol. THAT is what I was originally asking. HOW a person can know what to expect from different baffle designs.

So the above program allows you to move the drivers around on a simulated baffle, and it will show you the expected effect on the Freq response?
 
Separate mono subs provide flexibility regards positioning to help deal with low frequency room modes. A three way with bass extending into the modal region may be hard to position successfully

Yes. But my new listening room dictates the need for three ways. No getting around that.

So I am trying to figure out how to make an attractive speaker, while utilizing 2.8 cu ft cabinets, for the 12"s on bottom. Never had to do this before.
 
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@ Andy2 ... You say none of those I posted are easy on the eyes. I tend to agree. I have never built a three way before. I have always made narrow two way towers, and stereo subs.

Now I have a 12" forward firing woofer to contend with. And it is going in 2.8 cu feet. And I am just struggling to figure a way to make a 14" wide cabinet attractive. Do I make two? Just one huge box? I realize I have options, but am struggling to figure out something pleasing to the eye, while keeping sound principals foremost. I just know I can't imagine using a large square tower, ah la 80s Klipsh style.

I think side firing is out, since I want to xover around 300hz to the mids.

You could try 4-way so that the side woofer can be crossed lower ... maybe 100hz. Crossing 300hz maybe too high for side woofer. Look can be important in the long run. I've built may speakers and after awhile it's look that make me listen to them. I have dismantled many pairs of speakers because I just couldn't stand the look.
 
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I recommend two separate enclosures, mid/tweet stacked on bass bin. Allows flexibility of enclosure depth and other design parameters, adds rigidity, isolates vibration, makes building, handling, positioning much easier. They do not need to be structurally connected at all.

Unless you have precision woodworking tools, I would avoid lots of complex angles.

Peace,
Tom E
 
Everything you said makes sense until the last sentence.

Symmetry is the enemy of enclosure design. This is a concept few DIY builders understand. I see the same mistake made in many designs, even those from experienced builders.

Most symmetry means one is doubling any anomalies in response. From driver placement on the baffle to enclosure shape to bracing location, even the panels themselves, offset or unequal is best. Put a brace in the middle of a large panel and you have just made TWO panels of equal resonance. Put a tweeter in the center of a baffle and you have doubled diffraction effects. It affords no advantage, and it makes little sense. It might look prettier and help anal types sleep at night, and it is definitely easier to mass produce, stock, and sell, but for the DIY'er, most symmetry works against the ultimate goal.

Of course, between left and right speakers, everything MUST be a mirror image. Within a single speaker, the more left and right side, front and back, top and bottom vary from each other, the better.

Peace,
Tom E
 
@ Tom E ... I see separate bass bins done a lot. I've just not found any I find very attractive.

These are Pro Audio midrange drivers I'll be using, and only need .03 to .11 cu ft enclosures. And my Heil AMT tweeters are monopole. They do not need any volume. What this means to my mind, is I would have rather large bass bins. And on top, would be tiny cabinets .... BUT, I can make dummy cabinets ANY size and shape I want to. And I do mean ANY. I can build the upper cabinets ONLY for aesthetics, as far as shape goes. I can simply seal off the back of the mids with the correct volume, inside a larger cabinet, and fill the entire void with sand. Done.
So with THAT said, I am going to try and rough sketch the two things I can come up with, which MAY be more attractive than the standard bass bin/upper cabinet combo. I so welcome any suggestions anyone may have.

I do have extensive woodworking skills, and a nice wood shop. So I am not limited.
 
@ Tom E ... I see separate bass bins done a lot. I've just not found any I find very attractive.

These are Pro Audio midrange drivers I'll be using, and only need .03 to .11 cu ft enclosures. And my Heil AMT tweeters are monopole. They do not need any volume. What this means to my mind, is I would have rather large bass bins. And on top, would be tiny cabinets .... BUT, I can make dummy cabinets ANY size and shape I want to. And I do mean ANY. I can build the upper cabinets ONLY for aesthetics, as far as shape goes. I can simply seal off the back of the mids with the correct volume, inside a larger cabinet, and fill the entire void with sand. Done.
So with THAT said, I am going to try and rough sketch the two things I can come up with, which MAY be more attractive than the standard bass bin/upper cabinet combo. I so welcome any suggestions anyone may have.

I do have extensive woodworking skills, and a nice wood shop. So I am not limited.

It's nice that we now put more emphasis on look. With a three way and the woofer is that large, it won't be easy. I've just finished building a pair of monitor and although they sound really nice I just can't stand the look. The first thing I'll do is to rebuild the entire cabinet.
 
My attempts to free hand draw what I see in my head .... failed.:D

If I do separate matching cabinets. I am going to make baffles only 3/8" wider than the woofer, and the midrange, in their individual cabinets. At the edge of the baffle, will start a very large 2" roundover. This will make the cabinets total width wider, but will look amazing, and really tame diffraction. I will do this roundover on both cabinets ... matching.
 
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