Flat Cone woofers

[paradigm]

Anyone has a cutaway view of a flat cone woofer? How does these things work? Do they perform better than traditional conical shape woofers?

[fusseli]

Re: Flat Cone woofers

I'd imagine them to be something similar to the JL W7's W-cone? http://mobile.jlaudio.com/products_s...php?page_id=37

I find myself curious also.

[carlspeak]

Re: Flat Cone woofers

If you do the math, the surface area of a flat cone will be less than a standard conical shaped cone. Volume of air moved is directly proportional to the surface area of the cone.
Conclusion, a standard cone will move more air than a flat cone.

A flat cone will be lighter as pointed out in the well prepared marketing presentation at the link provided in a previous post.

There's always tradeoffs. ;)

[paradigm]

Re: Flat Cone woofers



What is the tradeoff? @carlspeak....The specs on this TB appears to exceeds some traditional conical drivers. Given the same specs with a flat cone versus a traditional cone woofer, are you saying that the traditonal cone will sound better?

I really need a sectional view of this driver to really understand how this thing works? Looking at the photo, is the top layer some sort of protection screen or dust cover?

Tang Band WT-1427G 10" Neo Subwoofer - Description
This unique subwoofer features a low profile (3-3/16"), long throw design, making it one of the few 10" subwoofers which can be mounted in-wall. This is made possible by a strong neodymium magnet assembly and large voice coil. When depth is an issue and bass is a must, look no further than this a one-of-a-kind, high quality subwoofer. Specifications: *Power Handling: 120 watts RMS/240 watts max *VCdia: 2-1/2" *Impedance: 4 ohms *Re: 3.2 ohms *Frequency range: 25-400 Hz *Fs: 25 Hz *SPL: 85 dB 1W/1m *Vas: 1.35 cu. ft. *Qms: 3.42 *Qes: 0.31 *Qts: 0.29 *Xmax 9.5 mm *Dimensions: Overall diameter 10-1/2", Cutout diameter 9-1/4", Depth 3-3/16".

[carlspeak]

Re: Flat Cone woofers

What is the tradeoff? @carlspeak....The specs on this TB appears to exceeds some traditional conical drivers. Given the same specs with a flat cone versus a traditional cone woofer, are you saying that the traditonal cone will sound better?

I really need a sectional view of this driver to really understand how this thing works? Looking at the photo, is the top layer some sort of protection screen or dust cover?

Tang Band WT-1427G 10" Neo Subwoofer - Description
This unique subwoofer features a low profile (3-3/16"), long throw design, making it one of the few 10" subwoofers which can be mounted in-wall. This is made possible by a strong neodymium magnet assembly and large voice coil. When depth is an issue and bass is a must, look no further than this a one-of-a-kind, high quality subwoofer. Specifications: *Power Handling: 120 watts RMS/240 watts max *VCdia: 2-1/2" *Impedance: 4 ohms *Re: 3.2 ohms *Frequency range: 25-400 Hz *Fs: 25 Hz *SPL: 85 dB 1W/1m *Vas: 1.35 cu. ft. *Qms: 3.42 *Qes: 0.31 *Qts: 0.29 *Xmax 9.5 mm *Dimensions: Overall diameter 10-1/2", Cutout diameter 9-1/4", Depth 3-3/16".

You seem to be comparing apples to oranges. I don't see a spec parameter for volume of air moved for a comparable sized 10 inch woofer with like magnet systems and X-max specs.

[MagicO309d]

Re: Flat Cone woofers

The old Kef B139 flat cone woofer was a solid molded chunk of styrofoam with some sort of black film applied to it's face. It was supposed to be the end-all-be-all of clean bass below 500 Hz back in the 1970's.

[Brian Steele]

Re: Flat Cone woofers

If you do the math, the surface area of a flat cone will be less than a standard conical shaped cone. Volume of air moved is directly proportional to the surface area of the cone.
Conclusion, a standard cone will move more air than a flat cone.

Sd is the effective radiating area of the driver, and its calculated using the equation 3.1416*D^2/4, where D is the diameter of the cone plus one-third of the surround at both ends of the measurement (LDC, 5th edition, page 20).

What part of that equation is influenced by the shape of the cone?

[paradigm]

Re: Flat Cone woofers

Sd is the effective radiating area of the driver, and its calculated using the equation 3.1416*D^2/4, where D is the diameter of the cone plus one-third of the surround at both ends of the measurement (LDC, 5th edition, page 20).

What part of that equation is influenced by the shape of the cone?

Good question....

[Herman Trivilino]

Re: Flat Cone woofers

Sd is the effective radiating area of the driver, and its calculated using the equation 3.1416*D^2/4, where D is the diameter of the cone plus one-third of the surround at both ends of the measurement (LDC, 5th edition, page 20).

What part of that equation is influenced by the shape of the cone?

None. That's the formula for the area of a (flat) circle. It doesn't take into account the fact that the shape is a cone. Either the increased area you get from a cone versus a flat circle is not relevant, or that formula applies only to flat drivers.

[Brian Steele]

Re: Flat Cone woofers

None. That's the formula for the area of a (flat) circle. It doesn't take into account the fact that the shape is a cone. Either the increased area you get from a cone versus a flat circle is not relevant, or that formula applies only to flat drivers.

Exactly. I've quoted the exact formula given in Vance Dickason's Loudspeaker Design Cookbook. The point is clear: the profile of the cone is irrelevant to Sd. All that matters is its effective diameter.

[Dirttracker73]

Re: Flat Cone woofers

Sd is the effective radiating area of the driver, and its calculated using the equation 3.1416*D^2/4, where D is the diameter of the cone plus one-third of the surround at both ends of the measurement (LDC, 5th edition, page 20).

What part of that equation is influenced by the shape of the cone?

+1. Displacement is dependent only on area and linear travel.

[anunnaki]

Re: Flat Cone woofers

If you do the math, the surface area of a flat cone will be less than a standard conical shaped cone. Volume of air moved is directly proportional to the surface area of the cone.
Conclusion, a standard cone will move more air than a flat cone.

A flat cone will be lighter as pointed out in the well prepared marketing presentation at the link provided in a previous post.

There's always tradeoffs. ;)

If one understands the principle & purpose behind the W-cone design it is easy to see that it is not just a marketing gimmick...

The shape of the cone matters not so long as it acts as a piston, does not breakup through the intended bandwidth, and the motor & suspension remain linear throughout its intended stroke.

[SnowmanTS]

Re: Flat Cone woofers

It seems intuitive to me that the frontal area of the cone would be the critical dimension to amount of air moved, this would agree with the definition of Sd given above. I'm thinking about it similarly to the frontal area used for drag calculations in aerodynamics. Its the projected area in a front view that is critical for moving air.

I don't really have any experience with flat cone drivers but my concern would be with rigidity of the cone. The curvature of a standard cone provides more strength compared to a flat sheet. Maybe this is handled with thicker material or some other construction type, a section of a flat cone driver would be nice to see.

[duanebro]

Re: Flat Cone woofers

+1. Displacement is dependent only on area and linear travel.

+1 The cone shape is used for strength. I saw a cut away of a flat cone somewhere... I think. The cross section looks like "cardboard". Only made from something different, and thicker. Think of a paper fan you made as a kid by folding paper back and forth. Then glue a piece of paper on both sides.

However it is made, or what shape, doesn't matter. As long as it is light and stiff it will work.

Flat cones are used to make the driver shallower, and because it looks cool, or at least different.

Duane

[dantheman]

Re: Flat Cone woofers

All things equal, the flat cone will break up earlier:

http://www.loudsoft.com/loudsoft/my%20files/Articles/Geometrical%20Stiffness%20of%20Loudspeaker%20Cones%20ALMA%202003.pdf

Dan